11. Resource Creation
Vulkan supports two primary resource types: buffers and images. Resources are views of memory with associated formatting and dimensionality. Buffers are essentially unformatted arrays of bytes whereas images contain format information, can be multidimensional and may have associated metadata.
11.1. Buffers
Buffers represent linear arrays of data which are used for various purposes by binding them to a graphics or compute pipeline via descriptor sets or via certain commands, or by directly specifying them as parameters to certain commands.
Buffers are represented by VkBuffer
handles:
// Provided by VK_VERSION_1_0
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkBuffer)
To create buffers, call:
// Provided by VK_VERSION_1_0
VkResult vkCreateBuffer(
VkDevice device,
const VkBufferCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkBuffer* pBuffer);
-
device
is the logical device that creates the buffer object. -
pCreateInfo
is a pointer to a VkBufferCreateInfo structure containing parameters affecting creation of the buffer. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter. -
pBuffer
is a pointer to a VkBuffer handle in which the resulting buffer object is returned.
The VkBufferCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkBufferCreateInfo {
VkStructureType sType;
const void* pNext;
VkBufferCreateFlags flags;
VkDeviceSize size;
VkBufferUsageFlags usage;
VkSharingMode sharingMode;
uint32_t queueFamilyIndexCount;
const uint32_t* pQueueFamilyIndices;
} VkBufferCreateInfo;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
flags
is a bitmask of VkBufferCreateFlagBits specifying additional parameters of the buffer. -
size
is the size in bytes of the buffer to be created. -
usage
is a bitmask of VkBufferUsageFlagBits specifying allowed usages of the buffer. -
sharingMode
is a VkSharingMode value specifying the sharing mode of the buffer when it will be accessed by multiple queue families. -
queueFamilyIndexCount
is the number of entries in thepQueueFamilyIndices
array. -
pQueueFamilyIndices
is a list of queue families that will access this buffer (ignored ifsharingMode
is notVK_SHARING_MODE_CONCURRENT
).
Bits which can be set in VkBufferCreateInfo::usage
, specifying
usage behavior of a buffer, are:
// Provided by VK_VERSION_1_0
typedef enum VkBufferUsageFlagBits {
VK_BUFFER_USAGE_TRANSFER_SRC_BIT = 0x00000001,
VK_BUFFER_USAGE_TRANSFER_DST_BIT = 0x00000002,
VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT = 0x00000004,
VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT = 0x00000008,
VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT = 0x00000010,
VK_BUFFER_USAGE_STORAGE_BUFFER_BIT = 0x00000020,
VK_BUFFER_USAGE_INDEX_BUFFER_BIT = 0x00000040,
VK_BUFFER_USAGE_VERTEX_BUFFER_BIT = 0x00000080,
VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT = 0x00000100,
// Provided by VK_VERSION_1_2
VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT = 0x00020000,
// Provided by VK_EXT_transform_feedback
VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_BUFFER_BIT_EXT = 0x00000800,
// Provided by VK_EXT_transform_feedback
VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT = 0x00001000,
// Provided by VK_EXT_conditional_rendering
VK_BUFFER_USAGE_CONDITIONAL_RENDERING_BIT_EXT = 0x00000200,
// Provided by VK_KHR_ray_tracing
VK_BUFFER_USAGE_RAY_TRACING_BIT_KHR = 0x00000400,
// Provided by VK_NV_ray_tracing
VK_BUFFER_USAGE_RAY_TRACING_BIT_NV = VK_BUFFER_USAGE_RAY_TRACING_BIT_KHR,
// Provided by VK_EXT_buffer_device_address
VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT_EXT = VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT,
// Provided by VK_KHR_buffer_device_address
VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT_KHR = VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT,
} VkBufferUsageFlagBits;
-
VK_BUFFER_USAGE_TRANSFER_SRC_BIT
specifies that the buffer can be used as the source of a transfer command (see the definition ofVK_PIPELINE_STAGE_TRANSFER_BIT
). -
VK_BUFFER_USAGE_TRANSFER_DST_BIT
specifies that the buffer can be used as the destination of a transfer command. -
VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT
specifies that the buffer can be used to create aVkBufferView
suitable for occupying aVkDescriptorSet
slot of typeVK_DESCRIPTOR_TYPE_UNIFORM_TEXEL_BUFFER
. -
VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT
specifies that the buffer can be used to create aVkBufferView
suitable for occupying aVkDescriptorSet
slot of typeVK_DESCRIPTOR_TYPE_STORAGE_TEXEL_BUFFER
. -
VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT
specifies that the buffer can be used in aVkDescriptorBufferInfo
suitable for occupying aVkDescriptorSet
slot either of typeVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER
orVK_DESCRIPTOR_TYPE_UNIFORM_BUFFER_DYNAMIC
. -
VK_BUFFER_USAGE_STORAGE_BUFFER_BIT
specifies that the buffer can be used in aVkDescriptorBufferInfo
suitable for occupying aVkDescriptorSet
slot either of typeVK_DESCRIPTOR_TYPE_STORAGE_BUFFER
orVK_DESCRIPTOR_TYPE_STORAGE_BUFFER_DYNAMIC
. -
VK_BUFFER_USAGE_INDEX_BUFFER_BIT
specifies that the buffer is suitable for passing as thebuffer
parameter tovkCmdBindIndexBuffer
. -
VK_BUFFER_USAGE_VERTEX_BUFFER_BIT
specifies that the buffer is suitable for passing as an element of thepBuffers
array tovkCmdBindVertexBuffers
. -
VK_BUFFER_USAGE_INDIRECT_BUFFER_BIT
specifies that the buffer is suitable for passing as thebuffer
parameter tovkCmdDrawIndirect
,vkCmdDrawIndexedIndirect
,vkCmdDrawMeshTasksIndirectNV
,vkCmdDrawMeshTasksIndirectCountNV
, orvkCmdDispatchIndirect
. It is also suitable for passing as thebuffer
member ofVkIndirectCommandsStreamNV
, orsequencesCountBuffer
orsequencesIndexBuffer
orpreprocessedBuffer
member ofVkGeneratedCommandsInfoNV
-
VK_BUFFER_USAGE_CONDITIONAL_RENDERING_BIT_EXT
specifies that the buffer is suitable for passing as thebuffer
parameter to vkCmdBeginConditionalRenderingEXT. -
VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_BUFFER_BIT_EXT
specifies that the buffer is suitable for using for binding as a transform feedback buffer with vkCmdBindTransformFeedbackBuffersEXT. -
VK_BUFFER_USAGE_TRANSFORM_FEEDBACK_COUNTER_BUFFER_BIT_EXT
specifies that the buffer is suitable for using as a counter buffer with vkCmdBeginTransformFeedbackEXT and vkCmdEndTransformFeedbackEXT. -
VK_BUFFER_USAGE_RAY_TRACING_BIT_KHR
specifies that the buffer is suitable for use in vkCmdTraceRaysKHR and vkCmdBuildAccelerationStructureKHR. -
VK_BUFFER_USAGE_SHADER_DEVICE_ADDRESS_BIT
specifies that the buffer can be used to retrieve a buffer device address via vkGetBufferDeviceAddress and use that address to access the buffer’s memory from a shader.
// Provided by VK_VERSION_1_0
typedef VkFlags VkBufferUsageFlags;
VkBufferUsageFlags
is a bitmask type for setting a mask of zero or
more VkBufferUsageFlagBits.
Bits which can be set in VkBufferCreateInfo::flags
, specifying
additional parameters of a buffer, are:
// Provided by VK_VERSION_1_0
typedef enum VkBufferCreateFlagBits {
VK_BUFFER_CREATE_SPARSE_BINDING_BIT = 0x00000001,
VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT = 0x00000002,
VK_BUFFER_CREATE_SPARSE_ALIASED_BIT = 0x00000004,
// Provided by VK_VERSION_1_1
VK_BUFFER_CREATE_PROTECTED_BIT = 0x00000008,
// Provided by VK_VERSION_1_2
VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT = 0x00000010,
// Provided by VK_EXT_buffer_device_address
VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT_EXT = VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT,
// Provided by VK_KHR_buffer_device_address
VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT_KHR = VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT,
} VkBufferCreateFlagBits;
-
VK_BUFFER_CREATE_SPARSE_BINDING_BIT
specifies that the buffer will be backed using sparse memory binding. -
VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT
specifies that the buffer can be partially backed using sparse memory binding. Buffers created with this flag must also be created with theVK_BUFFER_CREATE_SPARSE_BINDING_BIT
flag. -
VK_BUFFER_CREATE_SPARSE_ALIASED_BIT
specifies that the buffer will be backed using sparse memory binding with memory ranges that might also simultaneously be backing another buffer (or another portion of the same buffer). Buffers created with this flag must also be created with theVK_BUFFER_CREATE_SPARSE_BINDING_BIT
flag. -
VK_BUFFER_CREATE_PROTECTED_BIT
specifies that the buffer is a protected buffer. -
VK_BUFFER_CREATE_DEVICE_ADDRESS_CAPTURE_REPLAY_BIT
specifies that the buffer’s address can be saved and reused on a subsequent run (e.g. for trace capture and replay), see VkBufferOpaqueCaptureAddressCreateInfo for more detail.
See Sparse Resource Features and Physical Device Features for details of the sparse memory features supported on a device.
// Provided by VK_VERSION_1_0
typedef VkFlags VkBufferCreateFlags;
VkBufferCreateFlags
is a bitmask type for setting a mask of zero or
more VkBufferCreateFlagBits.
If the pNext
chain includes a
VkDedicatedAllocationBufferCreateInfoNV
structure, then that structure
includes an enable controlling whether the buffer will have a dedicated
memory allocation bound to it.
The VkDedicatedAllocationBufferCreateInfoNV
structure is defined as:
// Provided by VK_NV_dedicated_allocation
typedef struct VkDedicatedAllocationBufferCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkBool32 dedicatedAllocation;
} VkDedicatedAllocationBufferCreateInfoNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
dedicatedAllocation
specifies whether the buffer will have a dedicated allocation bound to it.
To define a set of external memory handle types that may be used as backing
store for a buffer, add a VkExternalMemoryBufferCreateInfo structure
to the pNext
chain of the VkBufferCreateInfo structure.
The VkExternalMemoryBufferCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkExternalMemoryBufferCreateInfo {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlags handleTypes;
} VkExternalMemoryBufferCreateInfo;
or the equivalent
// Provided by VK_KHR_external_memory
typedef VkExternalMemoryBufferCreateInfo VkExternalMemoryBufferCreateInfoKHR;
Note
A |
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
handleTypes
is a bitmask of VkExternalMemoryHandleTypeFlagBits specifying one or more external memory handle types.
To request a specific device address for a buffer, add a
VkBufferOpaqueCaptureAddressCreateInfo structure to the pNext
chain of the VkBufferCreateInfo structure.
The VkBufferOpaqueCaptureAddressCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_2
typedef struct VkBufferOpaqueCaptureAddressCreateInfo {
VkStructureType sType;
const void* pNext;
uint64_t opaqueCaptureAddress;
} VkBufferOpaqueCaptureAddressCreateInfo;
or the equivalent
// Provided by VK_KHR_buffer_device_address
typedef VkBufferOpaqueCaptureAddressCreateInfo VkBufferOpaqueCaptureAddressCreateInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
opaqueCaptureAddress
is the opaque capture address requested for the buffer.
If opaqueCaptureAddress
is zero, no specific address is requested.
If opaqueCaptureAddress
is not zero, then it should be an address
retrieved from vkGetBufferOpaqueCaptureAddress for an identically
created buffer on the same implementation.
If this structure is not present, it is as if opaqueCaptureAddress
is
zero.
Apps should avoid creating buffers with app-provided addresses and
implementation-provided addresses in the same process, to reduce the
likelihood of VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS
errors.
Note
The expected usage for this is that a trace capture/replay tool will add the
Implementations are expected to separate such buffers in the GPU address
space so normal allocations will avoid using these addresses.
Apps/tools should avoid mixing app-provided and implementation-provided
addresses for buffers created with
|
Alternatively, to
request a specific device address for a buffer, add a
VkBufferDeviceAddressCreateInfoEXT structure to the pNext
chain
of the VkBufferCreateInfo structure.
The VkBufferDeviceAddressCreateInfoEXT
structure is defined as:
// Provided by VK_EXT_buffer_device_address
typedef struct VkBufferDeviceAddressCreateInfoEXT {
VkStructureType sType;
const void* pNext;
VkDeviceAddress deviceAddress;
} VkBufferDeviceAddressCreateInfoEXT;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
deviceAddress
is the device address requested for the buffer.
If deviceAddress
is zero, no specific address is requested.
If deviceAddress
is not zero, then it must be an address retrieved
from an identically created buffer on the same implementation.
The buffer must also be bound to an identically created
VkDeviceMemory
object.
If this structure is not present, it is as if deviceAddress
is zero.
Apps should avoid creating buffers with app-provided addresses and
implementation-provided addresses in the same process, to reduce the
likelihood of VK_ERROR_INVALID_DEVICE_ADDRESS_EXT
errors.
To destroy a buffer, call:
// Provided by VK_VERSION_1_0
void vkDestroyBuffer(
VkDevice device,
VkBuffer buffer,
const VkAllocationCallbacks* pAllocator);
-
device
is the logical device that destroys the buffer. -
buffer
is the buffer to destroy. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter.
11.2. Buffer Views
A buffer view represents a contiguous range of a buffer and a specific format to be used to interpret the data. Buffer views are used to enable shaders to access buffer contents interpreted as formatted data. In order to create a valid buffer view, the buffer must have been created with at least one of the following usage flags:
-
VK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT
-
VK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT
Buffer views are represented by VkBufferView
handles:
// Provided by VK_VERSION_1_0
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkBufferView)
To create a buffer view, call:
// Provided by VK_VERSION_1_0
VkResult vkCreateBufferView(
VkDevice device,
const VkBufferViewCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkBufferView* pView);
-
device
is the logical device that creates the buffer view. -
pCreateInfo
is a pointer to a VkBufferViewCreateInfo structure containing parameters to be used to create the buffer. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter. -
pView
is a pointer to a VkBufferView handle in which the resulting buffer view object is returned.
The VkBufferViewCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkBufferViewCreateInfo {
VkStructureType sType;
const void* pNext;
VkBufferViewCreateFlags flags;
VkBuffer buffer;
VkFormat format;
VkDeviceSize offset;
VkDeviceSize range;
} VkBufferViewCreateInfo;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
flags
is reserved for future use. -
buffer
is a VkBuffer on which the view will be created. -
format
is a VkFormat describing the format of the data elements in the buffer. -
offset
is an offset in bytes from the base address of the buffer. Accesses to the buffer view from shaders use addressing that is relative to this starting offset. -
range
is a size in bytes of the buffer view. Ifrange
is equal toVK_WHOLE_SIZE
, the range fromoffset
to the end of the buffer is used. IfVK_WHOLE_SIZE
is used and the remaining size of the buffer is not a multiple of the texel block size offormat
, the nearest smaller multiple is used.
// Provided by VK_VERSION_1_0
typedef VkFlags VkBufferViewCreateFlags;
VkBufferViewCreateFlags
is a bitmask type for setting a mask, but is
currently reserved for future use.
To destroy a buffer view, call:
// Provided by VK_VERSION_1_0
void vkDestroyBufferView(
VkDevice device,
VkBufferView bufferView,
const VkAllocationCallbacks* pAllocator);
-
device
is the logical device that destroys the buffer view. -
bufferView
is the buffer view to destroy. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter.
11.3. Images
Images represent multidimensional - up to 3 - arrays of data which can be used for various purposes (e.g. attachments, textures), by binding them to a graphics or compute pipeline via descriptor sets, or by directly specifying them as parameters to certain commands.
Images are represented by VkImage
handles:
// Provided by VK_VERSION_1_0
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkImage)
To create images, call:
// Provided by VK_VERSION_1_0
VkResult vkCreateImage(
VkDevice device,
const VkImageCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkImage* pImage);
-
device
is the logical device that creates the image. -
pCreateInfo
is a pointer to a VkImageCreateInfo structure containing parameters to be used to create the image. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter. -
pImage
is a pointer to a VkImage handle in which the resulting image object is returned.
The VkImageCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkImageCreateInfo {
VkStructureType sType;
const void* pNext;
VkImageCreateFlags flags;
VkImageType imageType;
VkFormat format;
VkExtent3D extent;
uint32_t mipLevels;
uint32_t arrayLayers;
VkSampleCountFlagBits samples;
VkImageTiling tiling;
VkImageUsageFlags usage;
VkSharingMode sharingMode;
uint32_t queueFamilyIndexCount;
const uint32_t* pQueueFamilyIndices;
VkImageLayout initialLayout;
} VkImageCreateInfo;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
flags
is a bitmask of VkImageCreateFlagBits describing additional parameters of the image. -
imageType
is a VkImageType value specifying the basic dimensionality of the image. Layers in array textures do not count as a dimension for the purposes of the image type. -
format
is a VkFormat describing the format and type of the texel blocks that will be contained in the image. -
extent
is a VkExtent3D describing the number of data elements in each dimension of the base level. -
mipLevels
describes the number of levels of detail available for minified sampling of the image. -
arrayLayers
is the number of layers in the image. -
samples
is a VkSampleCountFlagBits specifying the number of samples per texel. -
tiling
is a VkImageTiling value specifying the tiling arrangement of the texel blocks in memory. -
usage
is a bitmask of VkImageUsageFlagBits describing the intended usage of the image. -
sharingMode
is a VkSharingMode value specifying the sharing mode of the image when it will be accessed by multiple queue families. -
queueFamilyIndexCount
is the number of entries in thepQueueFamilyIndices
array. -
pQueueFamilyIndices
is a list of queue families that will access this image (ignored ifsharingMode
is notVK_SHARING_MODE_CONCURRENT
). -
initialLayout
is a VkImageLayout value specifying the initial VkImageLayout of all image subresources of the image. See Image Layouts.
Images created with tiling
equal to VK_IMAGE_TILING_LINEAR
have
further restrictions on their limits and capabilities compared to images
created with tiling
equal to VK_IMAGE_TILING_OPTIMAL
.
Creation of images with tiling VK_IMAGE_TILING_LINEAR
may not be
supported unless other parameters meet all of the constraints:
-
imageType
isVK_IMAGE_TYPE_2D
-
format
is not a depth/stencil format -
mipLevels
is 1 -
arrayLayers
is 1 -
samples
isVK_SAMPLE_COUNT_1_BIT
-
usage
only includesVK_IMAGE_USAGE_TRANSFER_SRC_BIT
and/orVK_IMAGE_USAGE_TRANSFER_DST_BIT
Images created with a format
from one of those listed in
Formats requiring sampler Y′CBCR conversion for VK_IMAGE_ASPECT_COLOR_BIT
image views have further restrictions on
their limits and capabilities compared to images created with other formats.
Creation of images with a format requiring
Y′CBCR conversion may not
be supported unless other parameters meet all of the constraints:
-
imageType
isVK_IMAGE_TYPE_2D
-
mipLevels
is 1 -
arrayLayers
is 1 -
samples
isVK_SAMPLE_COUNT_1_BIT
Implementations may support additional limits and capabilities beyond those listed above.
To determine the set of valid usage
bits for a given format, call
vkGetPhysicalDeviceFormatProperties.
If the size of the resultant image would exceed maxResourceSize
, then
vkCreateImage
must fail and return
VK_ERROR_OUT_OF_DEVICE_MEMORY
.
This failure may occur even when all image creation parameters satisfy
their valid usage requirements.
Note
For images created without For images created with |
The VkImageStencilUsageCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_2
typedef struct VkImageStencilUsageCreateInfo {
VkStructureType sType;
const void* pNext;
VkImageUsageFlags stencilUsage;
} VkImageStencilUsageCreateInfo;
or the equivalent
// Provided by VK_EXT_separate_stencil_usage
typedef VkImageStencilUsageCreateInfo VkImageStencilUsageCreateInfoEXT;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
stencilUsage
is a bitmask of VkImageUsageFlagBits describing the intended usage of the stencil aspect of the image.
If the pNext
chain of VkImageCreateInfo includes a
VkImageStencilUsageCreateInfo
structure, then that structure includes
the usage flags specific to the stencil aspect of the image for an image
with a depth-stencil format.
This structure specifies image usages which only apply to the stencil aspect
of a depth/stencil format image.
When this structure is included in the pNext
chain of
VkImageCreateInfo, the stencil aspect of the image must only be used
as specified by stencilUsage
.
When this structure is not included in the pNext
chain of
VkImageCreateInfo, the stencil aspect of an image must only be used
as specified VkImageCreateInfo::usage
.
Use of other aspects of an image are unaffected by this structure.
This structure can also be included in the pNext
chain of
VkPhysicalDeviceImageFormatInfo2 to query additional capabilities
specific to image creation parameter combinations including a separate set
of usage flags for the stencil aspect of the image using
vkGetPhysicalDeviceImageFormatProperties2.
When this structure is not included in the pNext
chain of
VkPhysicalDeviceImageFormatInfo2
then the implicit value of
stencilUsage
matches that of
VkPhysicalDeviceImageFormatInfo2
::usage
.
If the pNext
chain includes a
VkDedicatedAllocationImageCreateInfoNV
structure, then that structure
includes an enable controlling whether the image will have a dedicated
memory allocation bound to it.
The VkDedicatedAllocationImageCreateInfoNV
structure is defined as:
// Provided by VK_NV_dedicated_allocation
typedef struct VkDedicatedAllocationImageCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkBool32 dedicatedAllocation;
} VkDedicatedAllocationImageCreateInfoNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
dedicatedAllocation
specifies whether the image will have a dedicated allocation bound to it.
Note
Using a dedicated allocation for color and depth/stencil attachments or other large images may improve performance on some devices. |
To define a set of external memory handle types that may be used as backing
store for an image, add a VkExternalMemoryImageCreateInfo structure to
the pNext
chain of the VkImageCreateInfo structure.
The VkExternalMemoryImageCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkExternalMemoryImageCreateInfo {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlags handleTypes;
} VkExternalMemoryImageCreateInfo;
or the equivalent
// Provided by VK_KHR_external_memory
typedef VkExternalMemoryImageCreateInfo VkExternalMemoryImageCreateInfoKHR;
Note
A |
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
handleTypes
is a bitmask of VkExternalMemoryHandleTypeFlagBits specifying one or more external memory handle types.
If the pNext
chain includes a VkExternalMemoryImageCreateInfoNV
structure, then that structure defines a set of external memory handle types
that may be used as backing store for the image.
The VkExternalMemoryImageCreateInfoNV
structure is defined as:
// Provided by VK_NV_external_memory
typedef struct VkExternalMemoryImageCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkExternalMemoryHandleTypeFlagsNV handleTypes;
} VkExternalMemoryImageCreateInfoNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
handleTypes
is a bitmask of VkExternalMemoryHandleTypeFlagBitsNV specifying one or more external memory handle types.
To create an image with an
external
format, add a VkExternalFormatANDROID
structure in the pNext
chain of VkImageCreateInfo.
VkExternalFormatANDROID
is defined as:
// Provided by VK_ANDROID_external_memory_android_hardware_buffer
typedef struct VkExternalFormatANDROID {
VkStructureType sType;
void* pNext;
uint64_t externalFormat;
} VkExternalFormatANDROID;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
externalFormat
is an implementation-defined identifier for the external format
If externalFormat
is zero, the effect is as if the
VkExternalFormatANDROID
structure was not present.
Otherwise, the image
will have the specified external format.
If the pNext
chain of VkImageCreateInfo includes a
VkImageSwapchainCreateInfoKHR
structure, then that structure includes
a swapchain handle indicating that the image will be bound to memory from
that swapchain.
The VkImageSwapchainCreateInfoKHR
structure is defined as:
// Provided by VK_KHR_swapchain with VK_VERSION_1_1, VK_KHR_device_group with VK_KHR_swapchain
typedef struct VkImageSwapchainCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkSwapchainKHR swapchain;
} VkImageSwapchainCreateInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
swapchain
is VK_NULL_HANDLE or a handle of a swapchain that the image will be bound to.
If the pNext
list of VkImageCreateInfo includes a
VkImageFormatListCreateInfo
structure, then that structure contains a
list of all formats that can be used when creating views of this image.
The VkImageFormatListCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_2
typedef struct VkImageFormatListCreateInfo {
VkStructureType sType;
const void* pNext;
uint32_t viewFormatCount;
const VkFormat* pViewFormats;
} VkImageFormatListCreateInfo;
or the equivalent
// Provided by VK_KHR_image_format_list
typedef VkImageFormatListCreateInfo VkImageFormatListCreateInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
viewFormatCount
is the number of entries in thepViewFormats
array. -
pViewFormats
is an array which lists of all formats which can be used when creating views of this image.
If viewFormatCount
is zero, pViewFormats
is ignored and the
image is created as if the VkImageFormatListCreateInfo
structure were
not included in the pNext
list of VkImageCreateInfo.
If the pNext
chain of VkImageCreateInfo includes a
VkImageDrmFormatModifierListCreateInfoEXT structure, then the image
will be created with one of the Linux DRM
format modifiers listed in the structure.
The choice of modifier is implementation-dependent.
The VkImageDrmFormatModifierListCreateInfoEXT structure is defined as:
// Provided by VK_EXT_image_drm_format_modifier
typedef struct VkImageDrmFormatModifierListCreateInfoEXT {
VkStructureType sType;
const void* pNext;
uint32_t drmFormatModifierCount;
const uint64_t* pDrmFormatModifiers;
} VkImageDrmFormatModifierListCreateInfoEXT;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
drmFormatModifierCount
is the length of thepDrmFormatModifiers
array. -
pDrmFormatModifiers
is a pointer to an array of Linux DRM format modifiers.
If the pNext
chain of VkImageCreateInfo includes a
VkImageDrmFormatModifierExplicitCreateInfoEXT structure, then the
image will be created with the Linux DRM
format modifier and memory layout defined by the structure.
The VkImageDrmFormatModifierExplicitCreateInfoEXT structure is defined as:
// Provided by VK_EXT_image_drm_format_modifier
typedef struct VkImageDrmFormatModifierExplicitCreateInfoEXT {
VkStructureType sType;
const void* pNext;
uint64_t drmFormatModifier;
uint32_t drmFormatModifierPlaneCount;
const VkSubresourceLayout* pPlaneLayouts;
} VkImageDrmFormatModifierExplicitCreateInfoEXT;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
drmFormatModifier
is the Linux DRM format modifier with which the image will be created. -
drmFormatModifierPlaneCount
is the number of memory planes in the image (as reported by VkDrmFormatModifierPropertiesEXT) as well as the length of thepPlaneLayouts
array. -
pPlaneLayouts
is a pointer to an array of VkSubresourceLayout structures describing the image’s memory planes.
The i
th member of pPlaneLayouts
describes the layout of the
image’s i
th memory plane (that is,
VK_IMAGE_ASPECT_MEMORY_PLANE_i_BIT_EXT
).
In each element of pPlaneLayouts
, the implementation must ignore
size
.
The implementation calculates the size of each plane, which the application
can query with vkGetImageSubresourceLayout.
When creating an image with
VkImageDrmFormatModifierExplicitCreateInfoEXT, it is the application’s
responsibility to satisfy all valid usage requirements.
However, the implementation must validate that the provided
pPlaneLayouts
, when combined with the provided drmFormatModifier
and other creation parameters in VkImageCreateInfo and its pNext
chain, produce a valid image.
(This validation is necessarily implementation-dependent and outside the
scope of Vulkan, and therefore not described by valid usage requirements).
If this validation fails, then vkCreateImage returns
VK_ERROR_INVALID_DRM_FORMAT_MODIFIER_PLANE_LAYOUT_EXT
.
Bits which can be set in VkImageCreateInfo::usage
, specifying
intended usage of an image, are:
// Provided by VK_VERSION_1_0
typedef enum VkImageUsageFlagBits {
VK_IMAGE_USAGE_TRANSFER_SRC_BIT = 0x00000001,
VK_IMAGE_USAGE_TRANSFER_DST_BIT = 0x00000002,
VK_IMAGE_USAGE_SAMPLED_BIT = 0x00000004,
VK_IMAGE_USAGE_STORAGE_BIT = 0x00000008,
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT = 0x00000010,
VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT = 0x00000020,
VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT = 0x00000040,
VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT = 0x00000080,
// Provided by VK_NV_shading_rate_image
VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV = 0x00000100,
// Provided by VK_EXT_fragment_density_map
VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT = 0x00000200,
} VkImageUsageFlagBits;
-
VK_IMAGE_USAGE_TRANSFER_SRC_BIT
specifies that the image can be used as the source of a transfer command. -
VK_IMAGE_USAGE_TRANSFER_DST_BIT
specifies that the image can be used as the destination of a transfer command. -
VK_IMAGE_USAGE_SAMPLED_BIT
specifies that the image can be used to create aVkImageView
suitable for occupying aVkDescriptorSet
slot either of typeVK_DESCRIPTOR_TYPE_SAMPLED_IMAGE
orVK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER
, and be sampled by a shader. -
VK_IMAGE_USAGE_STORAGE_BIT
specifies that the image can be used to create aVkImageView
suitable for occupying aVkDescriptorSet
slot of typeVK_DESCRIPTOR_TYPE_STORAGE_IMAGE
. -
VK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT
specifies that the image can be used to create aVkImageView
suitable for use as a color or resolve attachment in aVkFramebuffer
. -
VK_IMAGE_USAGE_DEPTH_STENCIL_ATTACHMENT_BIT
specifies that the image can be used to create aVkImageView
suitable for use as a depth/stencil or depth/stencil resolve attachment in aVkFramebuffer
. -
VK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT
specifies that the memory bound to this image will have been allocated with theVK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT
(see Memory Allocation for more detail). This bit can be set for any image that can be used to create aVkImageView
suitable for use as a color, resolve, depth/stencil, or input attachment. -
VK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT
specifies that the image can be used to create aVkImageView
suitable for occupyingVkDescriptorSet
slot of typeVK_DESCRIPTOR_TYPE_INPUT_ATTACHMENT
; be read from a shader as an input attachment; and be used as an input attachment in a framebuffer. -
VK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV
specifies that the image can be used to create aVkImageView
suitable for use as a shading rate image. -
VK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT
specifies that the image can be used to create aVkImageView
suitable for use as a fragment density map image.
// Provided by VK_VERSION_1_0
typedef VkFlags VkImageUsageFlags;
VkImageUsageFlags
is a bitmask type for setting a mask of zero or more
VkImageUsageFlagBits.
Bits which can be set in VkImageCreateInfo::flags
, specifying
additional parameters of an image, are:
// Provided by VK_VERSION_1_0
typedef enum VkImageCreateFlagBits {
VK_IMAGE_CREATE_SPARSE_BINDING_BIT = 0x00000001,
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT = 0x00000002,
VK_IMAGE_CREATE_SPARSE_ALIASED_BIT = 0x00000004,
VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT = 0x00000008,
VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT = 0x00000010,
// Provided by VK_VERSION_1_1
VK_IMAGE_CREATE_ALIAS_BIT = 0x00000400,
// Provided by VK_VERSION_1_1
VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT = 0x00000040,
// Provided by VK_VERSION_1_1
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT = 0x00000020,
// Provided by VK_VERSION_1_1
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT = 0x00000080,
// Provided by VK_VERSION_1_1
VK_IMAGE_CREATE_EXTENDED_USAGE_BIT = 0x00000100,
// Provided by VK_VERSION_1_1
VK_IMAGE_CREATE_PROTECTED_BIT = 0x00000800,
// Provided by VK_VERSION_1_1
VK_IMAGE_CREATE_DISJOINT_BIT = 0x00000200,
// Provided by VK_NV_corner_sampled_image
VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV = 0x00002000,
// Provided by VK_EXT_sample_locations
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT = 0x00001000,
// Provided by VK_EXT_fragment_density_map
VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT = 0x00004000,
// Provided by VK_KHR_device_group with VK_KHR_bind_memory2
VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT_KHR = VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT,
// Provided by VK_KHR_maintenance1
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT_KHR = VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT,
// Provided by VK_KHR_maintenance2
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT_KHR = VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT,
// Provided by VK_KHR_maintenance2
VK_IMAGE_CREATE_EXTENDED_USAGE_BIT_KHR = VK_IMAGE_CREATE_EXTENDED_USAGE_BIT,
// Provided by VK_KHR_sampler_ycbcr_conversion
VK_IMAGE_CREATE_DISJOINT_BIT_KHR = VK_IMAGE_CREATE_DISJOINT_BIT,
// Provided by VK_KHR_bind_memory2
VK_IMAGE_CREATE_ALIAS_BIT_KHR = VK_IMAGE_CREATE_ALIAS_BIT,
} VkImageCreateFlagBits;
-
VK_IMAGE_CREATE_SPARSE_BINDING_BIT
specifies that the image will be backed using sparse memory binding. -
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
specifies that the image can be partially backed using sparse memory binding. Images created with this flag must also be created with theVK_IMAGE_CREATE_SPARSE_BINDING_BIT
flag. -
VK_IMAGE_CREATE_SPARSE_ALIASED_BIT
specifies that the image will be backed using sparse memory binding with memory ranges that might also simultaneously be backing another image (or another portion of the same image). Images created with this flag must also be created with theVK_IMAGE_CREATE_SPARSE_BINDING_BIT
flag -
VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT
specifies that the image can be used to create aVkImageView
with a different format from the image. For multi-planar formats,VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT
specifies that aVkImageView
can be created of a plane of the image. -
VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT
specifies that the image can be used to create aVkImageView
of typeVK_IMAGE_VIEW_TYPE_CUBE
orVK_IMAGE_VIEW_TYPE_CUBE_ARRAY
. -
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT
specifies that the image can be used to create aVkImageView
of typeVK_IMAGE_VIEW_TYPE_2D
orVK_IMAGE_VIEW_TYPE_2D_ARRAY
. -
VK_IMAGE_CREATE_PROTECTED_BIT
specifies that the image is a protected image. -
VK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT
specifies that the image can be used with a non-zero value of thesplitInstanceBindRegionCount
member of a VkBindImageMemoryDeviceGroupInfo structure passed into vkBindImageMemory2. This flag also has the effect of making the image use the standard sparse image block dimensions. -
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT
specifies that the image having a compressed format can be used to create aVkImageView
with an uncompressed format where each texel in the image view corresponds to a compressed texel block of the image. -
VK_IMAGE_CREATE_EXTENDED_USAGE_BIT
specifies that the image can be created with usage flags that are not supported for the format the image is created with but are supported for at least one format aVkImageView
created from the image can have. -
VK_IMAGE_CREATE_DISJOINT_BIT
specifies that an image with a multi-planar format must have each plane separately bound to memory, rather than having a single memory binding for the whole image; the presence of this bit distinguishes a disjoint image from an image without this bit set. -
VK_IMAGE_CREATE_ALIAS_BIT
specifies that two images created with the same creation parameters and aliased to the same memory can interpret the contents of the memory consistently with each other, subject to the rules described in the Memory Aliasing section. This flag further specifies that each plane of a disjoint image can share an in-memory non-linear representation with single-plane images, and that a single-plane image can share an in-memory non-linear representation with a plane of a multi-planar disjoint image, according to the rules in Compatible formats of planes of multi-planar formats. If thepNext
chain includes a VkExternalMemoryImageCreateInfo or VkExternalMemoryImageCreateInfoNV structure whosehandleTypes
member is not0
, it is as ifVK_IMAGE_CREATE_ALIAS_BIT
is set. -
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT
specifies that an image with a depth or depth/stencil format can be used with custom sample locations when used as a depth/stencil attachment. -
VK_IMAGE_CREATE_CORNER_SAMPLED_BIT_NV
specifies that the image is a corner-sampled image. -
VK_IMAGE_CREATE_SUBSAMPLED_BIT_EXT
specifies that an image can be in a subsampled format which may be more optimal when written as an attachment by a render pass that has a fragment density map attachment. Accessing a subsampled image has additional considerations:-
Image data read as an image sampler will have undefined values if the sampler was not created with
flags
containingVK_SAMPLER_CREATE_SUBSAMPLED_BIT_EXT
or was not sampled through the use of a combined image sampler with an immutable sampler inVkDescriptorSetLayoutBinding
. -
Image data read with an input attachment will have undefined values if the contents were not written as an attachment in an earlier subpass of the same render pass.
-
Image data read as an image sampler in the fragment shader will be additionally be read by the device during
VK_PIPELINE_STAGE_VERTEX_SHADER_BIT
ifVkPhysicalDeviceFragmentDensityMap2PropertiesEXT
::subsampledCoarseReconstructionEarlyAccess
isVK_TRUE
and the sampler was created withflags
containingVK_SAMPLER_CREATE_SUBSAMPLED_COARSE_RECONSTRUCTION_BIT_EXT
. -
Image data read with load operations are resampled to the fragment density of the render pass if
VkPhysicalDeviceFragmentDensityMap2PropertiesEXT
::subsampledLoads
isVK_TRUE
. Otherwise, values of image data are undefined. -
Image contents outside of the render area take on undefined values if the image is stored as a render pass attachment.
-
See Sparse Resource Features and Sparse Physical Device Features for more details.
// Provided by VK_VERSION_1_0
typedef VkFlags VkImageCreateFlags;
VkImageCreateFlags
is a bitmask type for setting a mask of zero or
more VkImageCreateFlagBits.
Possible values of VkImageCreateInfo::imageType
, specifying the
basic dimensionality of an image, are:
// Provided by VK_VERSION_1_0
typedef enum VkImageType {
VK_IMAGE_TYPE_1D = 0,
VK_IMAGE_TYPE_2D = 1,
VK_IMAGE_TYPE_3D = 2,
} VkImageType;
-
VK_IMAGE_TYPE_1D
specifies a one-dimensional image. -
VK_IMAGE_TYPE_2D
specifies a two-dimensional image. -
VK_IMAGE_TYPE_3D
specifies a three-dimensional image.
Possible values of VkImageCreateInfo::tiling
, specifying the
tiling arrangement of texel blocks in an image, are:
// Provided by VK_VERSION_1_0
typedef enum VkImageTiling {
VK_IMAGE_TILING_OPTIMAL = 0,
VK_IMAGE_TILING_LINEAR = 1,
// Provided by VK_EXT_image_drm_format_modifier
VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT = 1000158000,
} VkImageTiling;
-
VK_IMAGE_TILING_OPTIMAL
specifies optimal tiling (texels are laid out in an implementation-dependent arrangement, for more optimal memory access). -
VK_IMAGE_TILING_LINEAR
specifies linear tiling (texels are laid out in memory in row-major order, possibly with some padding on each row). -
VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT
indicates that the image’s tiling is defined by a Linux DRM format modifier. The modifier is specified at image creation with VkImageDrmFormatModifierListCreateInfoEXT or VkImageDrmFormatModifierExplicitCreateInfoEXT, and can be queried with vkGetImageDrmFormatModifierPropertiesEXT.
To query the memory layout of an image subresource, call:
// Provided by VK_VERSION_1_0
void vkGetImageSubresourceLayout(
VkDevice device,
VkImage image,
const VkImageSubresource* pSubresource,
VkSubresourceLayout* pLayout);
-
device
is the logical device that owns the image. -
image
is the image whose layout is being queried. -
pSubresource
is a pointer to a VkImageSubresource structure selecting a specific image for the image subresource. -
pLayout
is a pointer to a VkSubresourceLayout structure in which the layout is returned.
If the image is linear, then the returned layout is valid for host access.
If the image’s
tiling is VK_IMAGE_TILING_LINEAR
and its
format is a multi-planar
format, then vkGetImageSubresourceLayout
describes one
format plane
of the image.
If the image’s tiling is VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT
, then
vkGetImageSubresourceLayout
describes one memory plane of the image.
If the image’s tiling is VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT
and
the image is non-linear, then the returned
layout has an implementation-dependent meaning; the vendor of the image’s
DRM format modifier may provide
documentation that explains how to interpret the returned layout.
vkGetImageSubresourceLayout
is invariant for the lifetime of a single
image.
However, the subresource layout of images in Android hardware buffer
external memory is not known until the image has been bound to memory, so
applications must not call vkGetImageSubresourceLayout for such an
image before it has been bound.
The VkImageSubresource
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkImageSubresource {
VkImageAspectFlags aspectMask;
uint32_t mipLevel;
uint32_t arrayLayer;
} VkImageSubresource;
-
aspectMask
is a VkImageAspectFlags selecting the image aspect. -
mipLevel
selects the mipmap level. -
arrayLayer
selects the array layer.
Information about the layout of the image subresource is returned in a
VkSubresourceLayout
structure:
// Provided by VK_VERSION_1_0
typedef struct VkSubresourceLayout {
VkDeviceSize offset;
VkDeviceSize size;
VkDeviceSize rowPitch;
VkDeviceSize arrayPitch;
VkDeviceSize depthPitch;
} VkSubresourceLayout;
-
offset
is the byte offset from the start of the image or the plane where the image subresource begins. -
size
is the size in bytes of the image subresource.size
includes any extra memory that is required based onrowPitch
. -
rowPitch
describes the number of bytes between each row of texels in an image. -
arrayPitch
describes the number of bytes between each array layer of an image. -
depthPitch
describes the number of bytes between each slice of 3D image.
If the image is linear, then rowPitch
,
arrayPitch
and depthPitch
describe the layout of the image
subresource in linear memory.
For uncompressed formats, rowPitch
is the number of bytes between
texels with the same x coordinate in adjacent rows (y coordinates differ by
one).
arrayPitch
is the number of bytes between texels with the same x and y
coordinate in adjacent array layers of the image (array layer values differ
by one).
depthPitch
is the number of bytes between texels with the same x and y
coordinate in adjacent slices of a 3D image (z coordinates differ by one).
Expressed as an addressing formula, the starting byte of a texel in the
image subresource has address:
// (x,y,z,layer) are in texel coordinates
address(x,y,z,layer) = layer*arrayPitch + z*depthPitch + y*rowPitch + x*elementSize + offset
For compressed formats, the rowPitch
is the number of bytes between
compressed texel blocks in adjacent rows.
arrayPitch
is the number of bytes between compressed texel blocks in
adjacent array layers.
depthPitch
is the number of bytes between compressed texel blocks in
adjacent slices of a 3D image.
// (x,y,z,layer) are in compressed texel block coordinates
address(x,y,z,layer) = layer*arrayPitch + z*depthPitch + y*rowPitch + x*compressedTexelBlockByteSize + offset;
The value of arrayPitch
is undefined for images that were not created
as arrays.
depthPitch
is defined only for 3D images.
If the image has a
single-plane
color format
and its tiling is VK_IMAGE_TILING_LINEAR
, then the aspectMask
member of VkImageSubresource
must be
VK_IMAGE_ASPECT_COLOR_BIT
.
If the image has a depth/stencil format
and its tiling is VK_IMAGE_TILING_LINEAR
, then aspectMask
must be either VK_IMAGE_ASPECT_DEPTH_BIT
or
VK_IMAGE_ASPECT_STENCIL_BIT
.
On implementations that store depth and stencil aspects separately, querying
each of these image subresource layouts will return a different offset
and size
representing the region of memory used for that aspect.
On implementations that store depth and stencil aspects interleaved, the
same offset
and size
are returned and represent the interleaved
memory allocation.
If the image has a multi-planar
format
and its tiling is VK_IMAGE_TILING_LINEAR
, then the aspectMask
member of VkImageSubresource
must be
VK_IMAGE_ASPECT_PLANE_0_BIT
, VK_IMAGE_ASPECT_PLANE_1_BIT
, or
(for 3-plane formats only) VK_IMAGE_ASPECT_PLANE_2_BIT
.
Querying each of these image subresource layouts will return a different
offset
and size
representing the region of memory used for that
plane.
If the image is disjoint, then the offset
is relative to the base
address of the plane.
If the image is non-disjoint, then the offset
is relative to the
base address of the image.
If the image’s tiling is VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT
, then
the aspectMask
member of VkImageSubresource
must be one of
VK_IMAGE_ASPECT_MEMORY_PLANE_i_BIT_EXT
, where the maximum allowed
plane index i
is defined by the
VkDrmFormatModifierPropertiesEXT::drmFormatModifierPlaneCount
associated with the image’s VkImageCreateInfo::format
and
modifier.
The memory range used by the subresource is described by offset
and
size
.
If the image is disjoint, then the offset
is relative to the base
address of the memory plane.
If the image is non-disjoint, then the offset
is relative to the
base address of the image.
If the image is non-linear, then
rowPitch
, arrayPitch
, and depthPitch
have an
implementation-dependent meaning.
If an image was created with VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT
,
then the image has a Linux DRM format
modifier.
To query the modifier, call:
// Provided by VK_EXT_image_drm_format_modifier
VkResult vkGetImageDrmFormatModifierPropertiesEXT(
VkDevice device,
VkImage image,
VkImageDrmFormatModifierPropertiesEXT* pProperties);
-
device
is the logical device that owns the image. -
image
is the queried image. -
pProperties
will return properties of the image’s DRM format modifier.
The VkImageDrmFormatModifierPropertiesEXT structure is defined as:
// Provided by VK_EXT_image_drm_format_modifier
typedef struct VkImageDrmFormatModifierPropertiesEXT {
VkStructureType sType;
void* pNext;
uint64_t drmFormatModifier;
} VkImageDrmFormatModifierPropertiesEXT;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
drmFormatModifier
returns the image’s Linux DRM format modifier.
If the image
was created with
VkImageDrmFormatModifierListCreateInfoEXT, then the returned
drmFormatModifier
must belong to the list of modifiers provided at
time of image creation in
VkImageDrmFormatModifierListCreateInfoEXT::pDrmFormatModifiers
.
If the image
was created with
VkImageDrmFormatModifierExplicitCreateInfoEXT, then the returned
drmFormatModifier
must be the modifier provided at time of image
creation in
VkImageDrmFormatModifierExplicitCreateInfoEXT::drmFormatModifier
.
To destroy an image, call:
// Provided by VK_VERSION_1_0
void vkDestroyImage(
VkDevice device,
VkImage image,
const VkAllocationCallbacks* pAllocator);
-
device
is the logical device that destroys the image. -
image
is the image to destroy. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter.
11.3.1. Image Format Features
Valid uses of a VkImage may depend on the image’s format features, defined below. Such constraints are documented in the affected valid usage statement.
-
If the image was created with
VK_IMAGE_TILING_LINEAR
, then its set of format features is the value of VkFormatProperties::linearTilingFeatures
found by calling vkGetPhysicalDeviceFormatProperties on the sameformat
as VkImageCreateInfo::format
. -
If the image was created with
VK_IMAGE_TILING_OPTIMAL
, but without an Android hardware buffer external format, then its set of format features is the value of VkFormatProperties::optimalTilingFeatures
found by calling vkGetPhysicalDeviceFormatProperties on the sameformat
as VkImageCreateInfo::format
. -
If the image was created with an Android hardware buffer external format, then its set of format features is the value of VkAndroidHardwareBufferFormatPropertiesANDROID::
formatFeatures
found by calling vkGetAndroidHardwareBufferPropertiesANDROID on the Android hardware buffer that was imported to the VkDeviceMemory to which the image is bound. -
If the image was created with
VK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT
, then:-
The image’s DRM format modifier is the value of VkImageDrmFormatModifierListCreateInfoEXT::
drmFormatModifier
found by calling vkGetImageDrmFormatModifierPropertiesEXT. -
Let VkDrmFormatModifierPropertiesListEXT::
pDrmFormatModifierProperties
be the array found by calling vkGetPhysicalDeviceFormatProperties2 on the sameformat
as VkImageCreateInfo::format
. -
Let
VkDrmFormatModifierPropertiesEXT prop
be an array element whosedrmFormatModifier
member is the value of the image’s DRM format modifier. -
Then the image set of format features is the value of taking the bitwise intersection over the collected
prop
::drmFormatModifierTilingFeatures
.
-
11.3.2. Corner-Sampled Images
A corner-sampled image is an image where unnormalized texel coordinates are centered on integer values rather than half-integer values.
A corner-sampled image has a number of differences compared to conventional texture image:
-
Texels are centered on integer coordinates. See Unnormalized Texel Coordinate Operations
-
Normalized coordinates are scaled using coord × (dim - 1) rather than coord × dim, where dim is the size of one dimension of the image. See normalized texel coordinate transform.
-
Partial derivatives are scaled using coord × (dim - 1) rather than coord × dim. See Scale Factor Operation.
-
Calculation of the next higher lod size goes according to ⌈dim / 2⌉ rather than ⌊dim / 2⌋. See Image Miplevel Sizing.
-
The minimum level size is 2x2 for 2D images and 2x2x2 for 3D images. See Image Miplevel Sizing.
Corner-sampling is only supported for 2D and 3D images.
When sampling a corner-sampled image, the sampler addressing mode must be
VK_SAMPLER_ADDRESS_MODE_CLAMP_TO_EDGE
.
Corner-sampled images are not supported as cubemaps or depth/stencil images.
11.3.3. Image Miplevel Sizing
A complete mipmap chain is the full set of miplevels, from the largest miplevel provided, down to the minimum miplevel size.
Conventional Images
For conventional images, the dimensions of each successive miplevel, n+1, are:
-
width
n+1 = max(⌊width
n/2⌋, 1) -
height
n+1 = max(⌊height
n/2⌋, 1) -
depth
n+1 = max(⌊depth
n/2⌋, 1)
where width
n, height
n, and depth
n
are the dimensions of the next larger miplevel, n.
The minimum miplevel size is:
-
1 for one-dimensional images,
-
1x1 for two-dimensional images, and
-
1x1x1 for three-dimensional images.
The number of levels in a complete mipmap chain is:
-
⌊log2(max(
width
0,height
0,depth
0))⌋ + 1
where width
0, height
0, and depth
0
are the dimensions of the largest (most detailed) miplevel, 0
.
Corner-Sampled Images
For corner-sampled images, the dimensions of each successive miplevel, n+1, are:
-
width
n+1 = max(⌈width
n/2⌉, 2) -
height
n+1 = max(⌈height
n/2⌉, 2) -
depth
n+1 = max(⌈depth
n/2⌉, 2)
where width
n, height
n, and depth
n
are the dimensions of the next larger miplevel, n.
The minimum miplevel size is:
-
2x2 for two-dimensional images, and
-
2x2x2 for three-dimensional images.
The number of levels in a complete mipmap chain is:
-
⌈log2(max(
width
0,height
0,depth
0))⌉
where width
0, height
0, and depth
0
are the dimensions of the largest (most detailed) miplevel, 0
.
11.4. Image Layouts
Images are stored in implementation-dependent opaque layouts in memory.
Each layout has limitations on what kinds of operations are supported for
image subresources using the layout.
At any given time, the data representing an image subresource in memory
exists in a particular layout which is determined by the most recent layout
transition that was performed on that image subresource.
Applications have control over which layout each image subresource uses, and
can transition an image subresource from one layout to another.
Transitions can happen with an image memory barrier, included as part of a
vkCmdPipelineBarrier or a vkCmdWaitEvents command buffer command
(see Image Memory Barriers), or as part of a subpass
dependency within a render pass (see VkSubpassDependency
).
The image layout is per-image subresource, and separate image subresources
of the same image can be in different layouts at the same time with one
exception - depth and stencil aspects of a given image subresource must
always be in the same layout.
Note
Each layout may offer optimal performance for a specific usage of image
memory.
For example, an image with a layout of
|
Upon creation, all image subresources of an image are initially in the same
layout, where that layout is selected by the
VkImageCreateInfo
::initialLayout
member.
The initialLayout
must be either VK_IMAGE_LAYOUT_UNDEFINED
or
VK_IMAGE_LAYOUT_PREINITIALIZED
.
If it is VK_IMAGE_LAYOUT_PREINITIALIZED
, then the image data can be
preinitialized by the host while using this layout, and the transition away
from this layout will preserve that data.
If it is VK_IMAGE_LAYOUT_UNDEFINED
, then the contents of the data are
considered to be undefined, and the transition away from this layout is not
guaranteed to preserve that data.
For either of these initial layouts, any image subresources must be
transitioned to another layout before they are accessed by the device.
Host access to image memory is only well-defined for
linear images and for image subresources of
those images which are currently in either the
VK_IMAGE_LAYOUT_PREINITIALIZED
or VK_IMAGE_LAYOUT_GENERAL
layout.
Calling vkGetImageSubresourceLayout for a linear image returns a
subresource layout mapping that is valid for either of those image layouts.
The set of image layouts consists of:
// Provided by VK_VERSION_1_0
typedef enum VkImageLayout {
VK_IMAGE_LAYOUT_UNDEFINED = 0,
VK_IMAGE_LAYOUT_GENERAL = 1,
VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL = 2,
VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL = 3,
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL = 4,
VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL = 5,
VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL = 6,
VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL = 7,
VK_IMAGE_LAYOUT_PREINITIALIZED = 8,
// Provided by VK_VERSION_1_1
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL = 1000117000,
// Provided by VK_VERSION_1_1
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL = 1000117001,
// Provided by VK_VERSION_1_2
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL = 1000241000,
// Provided by VK_VERSION_1_2
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL = 1000241001,
// Provided by VK_VERSION_1_2
VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL = 1000241002,
// Provided by VK_VERSION_1_2
VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL = 1000241003,
// Provided by VK_KHR_swapchain
VK_IMAGE_LAYOUT_PRESENT_SRC_KHR = 1000001002,
// Provided by VK_KHR_shared_presentable_image
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR = 1000111000,
// Provided by VK_NV_shading_rate_image
VK_IMAGE_LAYOUT_SHADING_RATE_OPTIMAL_NV = 1000164003,
// Provided by VK_EXT_fragment_density_map
VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT = 1000218000,
// Provided by VK_KHR_maintenance2
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL,
// Provided by VK_KHR_maintenance2
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL,
// Provided by VK_KHR_separate_depth_stencil_layouts
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL,
// Provided by VK_KHR_separate_depth_stencil_layouts
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL_KHR = VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL,
// Provided by VK_KHR_separate_depth_stencil_layouts
VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL_KHR = VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL,
// Provided by VK_KHR_separate_depth_stencil_layouts
VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL_KHR = VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL,
} VkImageLayout;
The type(s) of device access supported by each layout are:
-
VK_IMAGE_LAYOUT_UNDEFINED
does not support device access. This layout must only be used as theinitialLayout
member of VkImageCreateInfo orVkAttachmentDescription
, or as theoldLayout
in an image transition. When transitioning out of this layout, the contents of the memory are not guaranteed to be preserved. -
VK_IMAGE_LAYOUT_PREINITIALIZED
does not support device access. This layout must only be used as theinitialLayout
member of VkImageCreateInfo orVkAttachmentDescription
, or as theoldLayout
in an image transition. When transitioning out of this layout, the contents of the memory are preserved. This layout is intended to be used as the initial layout for an image whose contents are written by the host, and hence the data can be written to memory immediately, without first executing a layout transition. Currently,VK_IMAGE_LAYOUT_PREINITIALIZED
is only useful with linear images because there is not a standard layout defined forVK_IMAGE_TILING_OPTIMAL
images. -
VK_IMAGE_LAYOUT_GENERAL
supports all types of device access. -
VK_IMAGE_LAYOUT_COLOR_ATTACHMENT_OPTIMAL
must only be used as a color or resolve attachment in aVkFramebuffer
. This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_COLOR_ATTACHMENT_BIT
usage bit enabled. -
VK_IMAGE_LAYOUT_DEPTH_STENCIL_ATTACHMENT_OPTIMAL
specifies a layout for both the depth and stencil aspects of a depth/stencil format image allowing read and write access as a depth/stencil attachment. It is equivalent toVK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL
andVK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL
. -
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL
specifies a layout for both the depth and stencil aspects of a depth/stencil format image allowing read only access as a depth/stencil attachment or in shaders. It is equivalent toVK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL
andVK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL
. -
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL
specifies a layout for depth/stencil format images allowing read and write access to the stencil aspect as a stencil attachment, and read only access to the depth aspect as a depth attachment or in shaders. It is equivalent toVK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL
andVK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL
. -
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL
specifies a layout for depth/stencil format images allowing read and write access to the depth aspect as a depth attachment, and read only access to the stencil aspect as a stencil attachment or in shaders. It is equivalent toVK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL
andVK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL
. -
VK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_OPTIMAL
specifies a layout for the depth aspect of a depth/stencil format image allowing read and write access as a depth attachment. -
VK_IMAGE_LAYOUT_DEPTH_READ_ONLY_OPTIMAL
specifies a layout for the depth aspect of a depth/stencil format image allowing read-only access as a depth attachment or in shaders. -
VK_IMAGE_LAYOUT_STENCIL_ATTACHMENT_OPTIMAL
specifies a layout for the stencil aspect of a depth/stencil format image allowing read and write access as a stencil attachment. -
VK_IMAGE_LAYOUT_STENCIL_READ_ONLY_OPTIMAL
specifies a layout for the stencil aspect of a depth/stencil format image allowing read-only access as a stencil attachment or in shaders. -
VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL
must only be used as a read-only image in a shader (which can be read as a sampled image, combined image/sampler and/or input attachment). This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_SAMPLED_BIT
orVK_IMAGE_USAGE_INPUT_ATTACHMENT_BIT
usage bit enabled. -
VK_IMAGE_LAYOUT_TRANSFER_SRC_OPTIMAL
must only be used as a source image of a transfer command (see the definition ofVK_PIPELINE_STAGE_TRANSFER_BIT
). This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_TRANSFER_SRC_BIT
usage bit enabled. -
VK_IMAGE_LAYOUT_TRANSFER_DST_OPTIMAL
must only be used as a destination image of a transfer command. This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_TRANSFER_DST_BIT
usage bit enabled. -
VK_IMAGE_LAYOUT_PRESENT_SRC_KHR
must only be used for presenting a presentable image for display. A swapchain’s image must be transitioned to this layout before calling vkQueuePresentKHR, and must be transitioned away from this layout after calling vkAcquireNextImageKHR. -
VK_IMAGE_LAYOUT_SHARED_PRESENT_KHR
is valid only for shared presentable images, and must be used for any usage the image supports. -
VK_IMAGE_LAYOUT_SHADING_RATE_OPTIMAL_NV
must only be used as a read-only shading-rate-image. This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_SHADING_RATE_IMAGE_BIT_NV
usage bit enabled. -
VK_IMAGE_LAYOUT_FRAGMENT_DENSITY_MAP_OPTIMAL_EXT
must only be used as a fragment density map attachment in aVkRenderPass
. This layout is valid only for image subresources of images created with theVK_IMAGE_USAGE_FRAGMENT_DENSITY_MAP_BIT_EXT
usage bit enabled.
The layout of each image subresource is not a state of the image subresource
itself, but is rather a property of how the data in memory is organized, and
thus for each mechanism of accessing an image in the API the application
must specify a parameter or structure member that indicates which image
layout the image subresource(s) are considered to be in when the image will
be accessed.
For transfer commands, this is a parameter to the command (see Clear Commands
and Copy Commands).
For use as a framebuffer attachment, this is a member in the substructures
of the VkRenderPassCreateInfo (see Render Pass).
For use in a descriptor set, this is a member in the
VkDescriptorImageInfo
structure (see Descriptor Set Updates).
11.4.1. Image Layout Matching Rules
At the time that any command buffer command accessing an image executes on any queue, the layouts of the image subresources that are accessed must all match exactly the layout specified via the API controlling those accesses , except in case of accesses to an image with a depth/stencil format performed through descriptors referring to only a single aspect of the image, where the following relaxed matching rules apply:
-
Descriptors referring just to the depth aspect of a depth/stencil image only need to match in the image layout of the depth aspect, thus
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL
andVK_IMAGE_LAYOUT_DEPTH_READ_ONLY_STENCIL_ATTACHMENT_OPTIMAL
are considered to match. -
Descriptors referring just to the stencil aspect of a depth/stencil image only need to match in the image layout of the stencil aspect, thus
VK_IMAGE_LAYOUT_DEPTH_STENCIL_READ_ONLY_OPTIMAL
andVK_IMAGE_LAYOUT_DEPTH_ATTACHMENT_STENCIL_READ_ONLY_OPTIMAL
are considered to match .
When performing a layout transition on an image subresource, the old layout
value must either equal the current layout of the image subresource (at the
time the transition executes), or else be VK_IMAGE_LAYOUT_UNDEFINED
(implying that the contents of the image subresource need not be preserved).
The new layout used in a transition must not be
VK_IMAGE_LAYOUT_UNDEFINED
or VK_IMAGE_LAYOUT_PREINITIALIZED
.
The image layout of each image subresource of a depth/stencil image created
with VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT
is
dependent on the last sample locations used to render to the image
subresource as a depth/stencil attachment, thus applications must provide
the same sample locations that were last used to render to the given image
subresource whenever a layout transition of the image subresource happens,
otherwise the contents of the depth aspect of the image subresource become
undefined.
In addition, depth reads from a depth/stencil attachment referring to an
image subresource range of a depth/stencil image created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT
using
different sample locations than what have been last used to perform depth
writes to the image subresources of the same image subresource range return
undefined values.
Similarly, depth writes to a depth/stencil attachment referring to an image
subresource range of a depth/stencil image created with
VK_IMAGE_CREATE_SAMPLE_LOCATIONS_COMPATIBLE_DEPTH_BIT_EXT
using
different sample locations than what have been last used to perform depth
writes to the image subresources of the same image subresource range make
the contents of the depth aspect of those image subresources undefined.
11.5. Image Views
Image objects are not directly accessed by pipeline shaders for reading or writing image data. Instead, image views representing contiguous ranges of the image subresources and containing additional metadata are used for that purpose. Views must be created on images of compatible types, and must represent a valid subset of image subresources.
Image views are represented by VkImageView
handles:
// Provided by VK_VERSION_1_0
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkImageView)
The types of image views that can be created are:
// Provided by VK_VERSION_1_0
typedef enum VkImageViewType {
VK_IMAGE_VIEW_TYPE_1D = 0,
VK_IMAGE_VIEW_TYPE_2D = 1,
VK_IMAGE_VIEW_TYPE_3D = 2,
VK_IMAGE_VIEW_TYPE_CUBE = 3,
VK_IMAGE_VIEW_TYPE_1D_ARRAY = 4,
VK_IMAGE_VIEW_TYPE_2D_ARRAY = 5,
VK_IMAGE_VIEW_TYPE_CUBE_ARRAY = 6,
} VkImageViewType;
The exact image view type is partially implicit, based on the image’s type
and sample count, as well as the view creation parameters as described in
the image view compatibility table
for vkCreateImageView.
This table also shows which SPIR-V OpTypeImage
Dim
and
Arrayed
parameters correspond to each image view type.
To create an image view, call:
// Provided by VK_VERSION_1_0
VkResult vkCreateImageView(
VkDevice device,
const VkImageViewCreateInfo* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkImageView* pView);
-
device
is the logical device that creates the image view. -
pCreateInfo
is a pointer to aVkImageViewCreateInfo
structure containing parameters to be used to create the image view. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter. -
pView
is a pointer to a VkImageView handle in which the resulting image view object is returned.
The VkImageViewCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkImageViewCreateInfo {
VkStructureType sType;
const void* pNext;
VkImageViewCreateFlags flags;
VkImage image;
VkImageViewType viewType;
VkFormat format;
VkComponentMapping components;
VkImageSubresourceRange subresourceRange;
} VkImageViewCreateInfo;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
flags
is a bitmask of VkImageViewCreateFlagBits describing additional parameters of the image view. -
image
is a VkImage on which the view will be created. -
viewType
is a VkImageViewType value specifying the type of the image view. -
format
is a VkFormat describing the format and type used to interpret texel blocks in the image. -
components
is a VkComponentMapping specifies a remapping of color components (or of depth or stencil components after they have been converted into color components). -
subresourceRange
is a VkImageSubresourceRange selecting the set of mipmap levels and array layers to be accessible to the view.
Some of the image
creation parameters are inherited by the view.
In particular, image view creation inherits the implicit parameter
usage
specifying the allowed usages of the image view that, by
default, takes the value of the corresponding usage
parameter
specified in VkImageCreateInfo at image creation time.
If the image was has a depth-stencil format and was created with a
VkImageStencilUsageCreateInfo structure included in the pNext
chain of VkImageCreateInfo, the usage is calculated based on the
subresource.aspectMask
provided:
-
If
aspectMask
includes onlyVK_IMAGE_ASPECT_STENCIL_BIT
, the implicitusage
is equal to VkImageStencilUsageCreateInfo::stencilUsage
. -
If
aspectMask
includes onlyVK_IMAGE_ASPECT_DEPTH_BIT
, the implicitusage
is equal to VkImageCreateInfo::usage
. -
If both aspects are included in
aspectMask
, the implicitusage
is equal to the intersection of VkImageCreateInfo::usage
and VkImageStencilUsageCreateInfo::stencilUsage
. The implicitusage
can be overriden by adding a VkImageViewUsageCreateInfo structure to thepNext
chain.
If image
was created with the VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT
flag,
and if the format
of the image is not
multi-planar,
format
can be different from the image’s format, but if
image
was created without the
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT
flag and
they are not equal they must be compatible.
Image format compatibility is defined in the
Format Compatibility Classes section.
Views of compatible formats will have the same mapping between texel
coordinates and memory locations irrespective of the format
, with only
the interpretation of the bit pattern changing.
Note
Values intended to be used with one view format may not be exactly preserved when written or read through a different format. For example, an integer value that happens to have the bit pattern of a floating point denorm or NaN may be flushed or canonicalized when written or read through a view with a floating point format. Similarly, a value written through a signed normalized format that has a bit pattern exactly equal to -2b may be changed to -2b + 1 as described in Conversion from Normalized Fixed-Point to Floating-Point. |
If image
was created with the
VK_IMAGE_CREATE_BLOCK_TEXEL_VIEW_COMPATIBLE_BIT
flag, format
must be compatible with the image’s format as described above, or must
be an uncompressed format in which case it must be size-compatible with
the image’s format, as defined for
copying data between images In
this case the resulting image view’s texel dimensions equal the dimensions
of the selected mip level divided by the compressed texel block size and
rounded up.
The VkComponentMapping components
member describes a remapping
from components of the image to components of the vector returned by shader
image instructions.
This remapping must be the identity swizzle for storage image descriptors,
input attachment descriptors,
framebuffer attachments, and any VkImageView
used with a combined
image sampler that enables sampler Y’CBCR
conversion.
If the image view is to be used with a sampler which supports
sampler Y′CBCR conversion, an identically
defined object of type VkSamplerYcbcrConversion to that used to
create the sampler must be passed to vkCreateImageView in a
VkSamplerYcbcrConversionInfo included in the pNext
chain of
VkImageViewCreateInfo.
Conversely, if a VkSamplerYcbcrConversion object is passed to
vkCreateImageView, an identically defined
VkSamplerYcbcrConversion object must be used when sampling the image.
If the image has a
multi-planar format
and
subresourceRange.aspectMask
is VK_IMAGE_ASPECT_COLOR_BIT
,
format
must be identical to the image format
, and the sampler
to be used with the image view must enable
sampler Y′CBCR conversion.
If image
was created with the VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT
and the image has a
multi-planar format
,
and if subresourceRange.aspectMask
is
VK_IMAGE_ASPECT_PLANE_0_BIT
, VK_IMAGE_ASPECT_PLANE_1_BIT
, or
VK_IMAGE_ASPECT_PLANE_2_BIT
, format
must be
compatible with the corresponding plane of the
image, and the sampler to be used with the image view must not enable
sampler Y′CBCR conversion.
The width
and height
of the single-plane image view must be
derived from the multi-planar image’s dimensions in the manner listed for
plane compatibility for the plane.
Any view of an image plane will have the same mapping between texel coordinates and memory locations as used by the channels of the color aspect, subject to the formulae relating texel coordinates to lower-resolution planes as described in Chroma Reconstruction. That is, if an R or B plane has a reduced resolution relative to the G plane of the multi-planar image, the image view operates using the (uplane, vplane) unnormalized coordinates of the reduced-resolution plane, and these coordinates access the same memory locations as the (ucolor, vcolor) unnormalized coordinates of the color aspect for which chroma reconstruction operations operate on the same (uplane, vplane) or (iplane, jplane) coordinates.
Dim, Arrayed, MS | Image parameters | View parameters |
---|---|---|
|
|
|
1D, 0, 0 |
|
|
1D, 1, 0 |
|
|
2D, 0, 0 |
|
|
2D, 1, 0 |
|
|
2D, 0, 1 |
|
|
2D, 1, 1 |
|
|
CUBE, 0, 0 |
|
|
CUBE, 1, 0 |
|
|
3D, 0, 0 |
|
|
3D, 0, 0 |
|
|
3D, 0, 0 |
|
|
Bits which can be set in VkImageViewCreateInfo::flags
,
specifying additional parameters of an image, are:
// Provided by VK_VERSION_1_0
typedef enum VkImageViewCreateFlagBits {
// Provided by VK_EXT_fragment_density_map
VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DYNAMIC_BIT_EXT = 0x00000001,
// Provided by VK_EXT_fragment_density_map2
VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DEFERRED_BIT_EXT = 0x00000002,
} VkImageViewCreateFlagBits;
-
VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DYNAMIC_BIT_EXT
specifies that the fragment density map will be read by device duringVK_PIPELINE_STAGE_FRAGMENT_DENSITY_PROCESS_BIT_EXT
-
VK_IMAGE_VIEW_CREATE_FRAGMENT_DENSITY_MAP_DEFERRED_BIT_EXT
specifies that the fragment density map will be read by the host duringVkEndCommandBuffer
for the primary command buffer that the render pass is recorded into
// Provided by VK_VERSION_1_0
typedef VkFlags VkImageViewCreateFlags;
VkImageViewCreateFlags
is a bitmask type for setting a mask of zero or
more VkImageViewCreateFlagBits.
The set of usages for the created image view can be restricted compared to
the parent image’s usage
flags by adding a
VkImageViewUsageCreateInfo
structure to the pNext
chain of
VkImageViewCreateInfo.
The VkImageViewUsageCreateInfo
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkImageViewUsageCreateInfo {
VkStructureType sType;
const void* pNext;
VkImageUsageFlags usage;
} VkImageViewUsageCreateInfo;
or the equivalent
// Provided by VK_KHR_maintenance2
typedef VkImageViewUsageCreateInfo VkImageViewUsageCreateInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
usage
is a bitmask describing the allowed usages of the image view. See VkImageUsageFlagBits for a description of the supported bits.
When this structure is chained to VkImageViewCreateInfo the
usage
field overrides the implicit usage
parameter inherited
from image creation time and its value is used instead for the purposes of
determining the valid usage conditions of VkImageViewCreateInfo.
The VkImageSubresourceRange
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkImageSubresourceRange {
VkImageAspectFlags aspectMask;
uint32_t baseMipLevel;
uint32_t levelCount;
uint32_t baseArrayLayer;
uint32_t layerCount;
} VkImageSubresourceRange;
-
aspectMask
is a bitmask of VkImageAspectFlagBits specifying which aspect(s) of the image are included in the view. -
baseMipLevel
is the first mipmap level accessible to the view. -
levelCount
is the number of mipmap levels (starting frombaseMipLevel
) accessible to the view. -
baseArrayLayer
is the first array layer accessible to the view. -
layerCount
is the number of array layers (starting frombaseArrayLayer
) accessible to the view.
The number of mipmap levels and array layers must be a subset of the image
subresources in the image.
If an application wants to use all mip levels or layers in an image after
the baseMipLevel
or baseArrayLayer
, it can set levelCount
and layerCount
to the special values VK_REMAINING_MIP_LEVELS
and
VK_REMAINING_ARRAY_LAYERS
without knowing the exact number of mip
levels or layers.
For cube and cube array image views, the layers of the image view starting
at baseArrayLayer
correspond to faces in the order +X, -X, +Y, -Y, +Z,
-Z.
For cube arrays, each set of six sequential layers is a single cube, so the
number of cube maps in a cube map array view is layerCount
/ 6, and
image array layer (baseArrayLayer
+ i) is face index
(i mod 6) of cube i / 6.
If the number of layers in the view, whether set explicitly in
layerCount
or implied by VK_REMAINING_ARRAY_LAYERS
, is not a
multiple of 6, the last cube map in the array must not be accessed.
aspectMask
must be only VK_IMAGE_ASPECT_COLOR_BIT
,
VK_IMAGE_ASPECT_DEPTH_BIT
or VK_IMAGE_ASPECT_STENCIL_BIT
if
format
is a color, depth-only or stencil-only format,
respectively, except if format
is a
multi-planar format.
If using a depth/stencil format with both depth and stencil components,
aspectMask
must include at least one of
VK_IMAGE_ASPECT_DEPTH_BIT
and VK_IMAGE_ASPECT_STENCIL_BIT
, and
can include both.
When the VkImageSubresourceRange
structure is used to select a subset
of the slices of a 3D image’s mip level in order to create a 2D or 2D array
image view of a 3D image created with
VK_IMAGE_CREATE_2D_ARRAY_COMPATIBLE_BIT
, baseArrayLayer
and
layerCount
specify the first slice index and the number of slices to
include in the created image view.
Such an image view can be used as a framebuffer attachment that refers only
to the specified range of slices of the selected mip level.
However, any layout transitions performed on such an attachment view during
a render pass instance still apply to the entire subresource referenced
which includes all the slices of the selected mip level.
When using an image view of a depth/stencil image to populate a descriptor
set (e.g. for sampling in the shader, or for use as an input attachment),
the aspectMask
must only include one bit and selects whether the
image view is used for depth reads (i.e. using a floating-point sampler or
input attachment in the shader) or stencil reads (i.e. using an unsigned
integer sampler or input attachment in the shader).
When an image view of a depth/stencil image is used as a depth/stencil
framebuffer attachment, the aspectMask
is ignored and both depth and
stencil image subresources are used.
When creating a VkImageView
, if sampler
Y′CBCR conversion is enabled in the sampler, the aspectMask
of a
subresourceRange
used by the VkImageView
must be
VK_IMAGE_ASPECT_COLOR_BIT
.
When creating a VkImageView
, if sampler Y′CBCR conversion is not
enabled in the sampler and the image format
is
multi-planar, the image must
have been created with VK_IMAGE_CREATE_MUTABLE_FORMAT_BIT
, and the
aspectMask
of the VkImageView
’s subresourceRange
must be
VK_IMAGE_ASPECT_PLANE_0_BIT
, VK_IMAGE_ASPECT_PLANE_1_BIT
or
VK_IMAGE_ASPECT_PLANE_2_BIT
.
Bits which can be set in an aspect mask to specify aspects of an image for purposes such as identifying a subresource, are:
// Provided by VK_VERSION_1_0
typedef enum VkImageAspectFlagBits {
VK_IMAGE_ASPECT_COLOR_BIT = 0x00000001,
VK_IMAGE_ASPECT_DEPTH_BIT = 0x00000002,
VK_IMAGE_ASPECT_STENCIL_BIT = 0x00000004,
VK_IMAGE_ASPECT_METADATA_BIT = 0x00000008,
// Provided by VK_VERSION_1_1
VK_IMAGE_ASPECT_PLANE_0_BIT = 0x00000010,
// Provided by VK_VERSION_1_1
VK_IMAGE_ASPECT_PLANE_1_BIT = 0x00000020,
// Provided by VK_VERSION_1_1
VK_IMAGE_ASPECT_PLANE_2_BIT = 0x00000040,
// Provided by VK_EXT_image_drm_format_modifier
VK_IMAGE_ASPECT_MEMORY_PLANE_0_BIT_EXT = 0x00000080,
// Provided by VK_EXT_image_drm_format_modifier
VK_IMAGE_ASPECT_MEMORY_PLANE_1_BIT_EXT = 0x00000100,
// Provided by VK_EXT_image_drm_format_modifier
VK_IMAGE_ASPECT_MEMORY_PLANE_2_BIT_EXT = 0x00000200,
// Provided by VK_EXT_image_drm_format_modifier
VK_IMAGE_ASPECT_MEMORY_PLANE_3_BIT_EXT = 0x00000400,
// Provided by VK_KHR_sampler_ycbcr_conversion
VK_IMAGE_ASPECT_PLANE_0_BIT_KHR = VK_IMAGE_ASPECT_PLANE_0_BIT,
// Provided by VK_KHR_sampler_ycbcr_conversion
VK_IMAGE_ASPECT_PLANE_1_BIT_KHR = VK_IMAGE_ASPECT_PLANE_1_BIT,
// Provided by VK_KHR_sampler_ycbcr_conversion
VK_IMAGE_ASPECT_PLANE_2_BIT_KHR = VK_IMAGE_ASPECT_PLANE_2_BIT,
} VkImageAspectFlagBits;
-
VK_IMAGE_ASPECT_COLOR_BIT
specifies the color aspect. -
VK_IMAGE_ASPECT_DEPTH_BIT
specifies the depth aspect. -
VK_IMAGE_ASPECT_STENCIL_BIT
specifies the stencil aspect. -
VK_IMAGE_ASPECT_METADATA_BIT
specifies the metadata aspect, used for sparse sparse resource operations. -
VK_IMAGE_ASPECT_PLANE_0_BIT
specifies plane 0 of a multi-planar image format. -
VK_IMAGE_ASPECT_PLANE_1_BIT
specifies plane 1 of a multi-planar image format. -
VK_IMAGE_ASPECT_PLANE_2_BIT
specifies plane 2 of a multi-planar image format. -
VK_IMAGE_ASPECT_MEMORY_PLANE_0_BIT_EXT
specifies memory plane 0. -
VK_IMAGE_ASPECT_MEMORY_PLANE_1_BIT_EXT
specifies memory plane 1. -
VK_IMAGE_ASPECT_MEMORY_PLANE_2_BIT_EXT
specifies memory plane 2. -
VK_IMAGE_ASPECT_MEMORY_PLANE_3_BIT_EXT
specifies memory plane 3.
// Provided by VK_VERSION_1_0
typedef VkFlags VkImageAspectFlags;
VkImageAspectFlags
is a bitmask type for setting a mask of zero or
more VkImageAspectFlagBits.
The VkComponentMapping
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkComponentMapping {
VkComponentSwizzle r;
VkComponentSwizzle g;
VkComponentSwizzle b;
VkComponentSwizzle a;
} VkComponentMapping;
-
r
is a VkComponentSwizzle specifying the component value placed in the R component of the output vector. -
g
is a VkComponentSwizzle specifying the component value placed in the G component of the output vector. -
b
is a VkComponentSwizzle specifying the component value placed in the B component of the output vector. -
a
is a VkComponentSwizzle specifying the component value placed in the A component of the output vector.
Possible values of the members of VkComponentMapping, specifying the component values placed in each component of the output vector, are:
// Provided by VK_VERSION_1_0
typedef enum VkComponentSwizzle {
VK_COMPONENT_SWIZZLE_IDENTITY = 0,
VK_COMPONENT_SWIZZLE_ZERO = 1,
VK_COMPONENT_SWIZZLE_ONE = 2,
VK_COMPONENT_SWIZZLE_R = 3,
VK_COMPONENT_SWIZZLE_G = 4,
VK_COMPONENT_SWIZZLE_B = 5,
VK_COMPONENT_SWIZZLE_A = 6,
} VkComponentSwizzle;
-
VK_COMPONENT_SWIZZLE_IDENTITY
specifies that the component is set to the identity swizzle. -
VK_COMPONENT_SWIZZLE_ZERO
specifies that the component is set to zero. -
VK_COMPONENT_SWIZZLE_ONE
specifies that the component is set to either 1 or 1.0, depending on whether the type of the image view format is integer or floating-point respectively, as determined by the Format Definition section for each VkFormat. -
VK_COMPONENT_SWIZZLE_R
specifies that the component is set to the value of the R component of the image. -
VK_COMPONENT_SWIZZLE_G
specifies that the component is set to the value of the G component of the image. -
VK_COMPONENT_SWIZZLE_B
specifies that the component is set to the value of the B component of the image. -
VK_COMPONENT_SWIZZLE_A
specifies that the component is set to the value of the A component of the image.
Setting the identity swizzle on a component is equivalent to setting the identity mapping on that component. That is:
Component | Identity Mapping |
---|---|
|
|
|
|
|
|
|
|
If the pNext
list includes a VkImageViewASTCDecodeModeEXT
structure, then that structure includes a parameter specifying the decode
mode for image views using ASTC compressed formats.
The VkImageViewASTCDecodeModeEXT
structure is defined as:
// Provided by VK_EXT_astc_decode_mode
typedef struct VkImageViewASTCDecodeModeEXT {
VkStructureType sType;
const void* pNext;
VkFormat decodeMode;
} VkImageViewASTCDecodeModeEXT;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
decodeMode
is the intermediate format used to decode ASTC compressed formats.
If format
uses sRGB encoding then the decodeMode
has no effect.
To destroy an image view, call:
// Provided by VK_VERSION_1_0
void vkDestroyImageView(
VkDevice device,
VkImageView imageView,
const VkAllocationCallbacks* pAllocator);
-
device
is the logical device that destroys the image view. -
imageView
is the image view to destroy. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter.
To get the handle for an image view, call:
// Provided by VK_NVX_image_view_handle
uint32_t vkGetImageViewHandleNVX(
VkDevice device,
const VkImageViewHandleInfoNVX* pInfo);
-
device
is the logical device that owns the image view. -
pInfo
describes the image view to query and type of handle.
The VkImageViewHandleInfoNVX
structure is defined as:
// Provided by VK_NVX_image_view_handle
typedef struct VkImageViewHandleInfoNVX {
VkStructureType sType;
const void* pNext;
VkImageView imageView;
VkDescriptorType descriptorType;
VkSampler sampler;
} VkImageViewHandleInfoNVX;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
imageView
is the image view to query. -
descriptorType
is the type of descriptor for which to query a handle. -
sampler
is the sampler to combine with the image view when generating the handle.
To get the device address for an image view, call:
// Provided by VK_NVX_image_view_handle
VkResult vkGetImageViewAddressNVX(
VkDevice device,
VkImageView imageView,
VkImageViewAddressPropertiesNVX* pProperties);
-
device
is the logical device that owns the image view. -
imageView
is a handle to the image view. -
pProperties
contains the device address and size when the call returns.
The VkImageViewAddressPropertiesNVX
structure is defined as:
// Provided by VK_NVX_image_view_handle
typedef struct VkImageViewAddressPropertiesNVX {
VkStructureType sType;
void* pNext;
VkDeviceAddress deviceAddress;
VkDeviceSize size;
} VkImageViewAddressPropertiesNVX;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
deviceAddress
is the device address of the image view. -
size
is the size in bytes of the image view device memory.
11.5.1. Image View Format Features
Valid uses of a VkImageView may depend on the image view’s format features, defined below. Such constraints are documented in the affected valid usage statement.
-
If VkImageViewCreateInfo::
image
was created withVK_IMAGE_TILING_LINEAR
, then the image view’s set of format features is the value of VkFormatProperties::linearTilingFeatures
found by calling vkGetPhysicalDeviceFormatProperties on the sameformat
as VkImageViewCreateInfo::format
. -
If VkImageViewCreateInfo::
image
was created withVK_IMAGE_TILING_OPTIMAL
, but without an Android hardware buffer external format, then the image view’s set of format features is the value of VkFormatProperties::optimalTilingFeatures
found by calling vkGetPhysicalDeviceFormatProperties on the sameformat
as VkImageViewCreateInfo::format
. -
If VkImageViewCreateInfo::
image
was created with an Android hardware buffer external format, then the image views’s set of format features is the value of VkAndroidHardwareBufferFormatPropertiesANDROID::formatFeatures
found by calling vkGetAndroidHardwareBufferPropertiesANDROID on the Android hardware buffer that was imported to the VkDeviceMemory to which the VkImageViewCreateInfo::image
is bound. -
If VkImageViewCreateInfo::
image
was created withVK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT
, then:-
The image’s DRM format modifier is the value of VkImageDrmFormatModifierListCreateInfoEXT::
drmFormatModifier
found by calling vkGetImageDrmFormatModifierPropertiesEXT. -
Let VkDrmFormatModifierPropertiesListEXT::
pDrmFormatModifierProperties
be the array found by calling vkGetPhysicalDeviceFormatProperties2 on the sameformat
as VkImageViewCreateInfo::format
. -
Let
VkDrmFormatModifierPropertiesEXT prop
be an array element whosedrmFormatModifier
member is the value of the image’s DRM format modifier. -
Then the image view’s set of format features is the value of taking the bitwise intersection, over the collected
prop
::drmFormatModifierTilingFeatures
.
-
11.6. Resource Memory Association
Resources are initially created as virtual allocations with no backing memory. Device memory is allocated separately (see Device Memory) and then associated with the resource. This association is done differently for sparse and non-sparse resources.
Resources created with any of the sparse creation flags are considered sparse resources. Resources created without these flags are non-sparse. The details on resource memory association for sparse resources is described in Sparse Resources.
Non-sparse resources must be bound completely and contiguously to a single
VkDeviceMemory
object before the resource is passed as a parameter to
any of the following operations:
-
creating image or buffer views
-
updating descriptor sets
-
recording commands in a command buffer
Once bound, the memory binding is immutable for the lifetime of the resource.
In a logical device representing more than one physical device, buffer and image resources exist on all physical devices but can be bound to memory differently on each. Each such replicated resource is an instance of the resource. For sparse resources, each instance can be bound to memory arbitrarily differently. For non-sparse resources, each instance can either be bound to the local or a peer instance of the memory, or for images can be bound to rectangular regions from the local and/or peer instances. When a resource is used in a descriptor set, each physical device interprets the descriptor according to its own instance’s binding to memory.
Note
There are no new copy commands to transfer data between physical devices. Instead, an application can create a resource with a peer mapping and use it as the source or destination of a transfer command executed by a single physical device to copy the data from one physical device to another. |
To determine the memory requirements for a buffer resource, call:
// Provided by VK_VERSION_1_0
void vkGetBufferMemoryRequirements(
VkDevice device,
VkBuffer buffer,
VkMemoryRequirements* pMemoryRequirements);
-
device
is the logical device that owns the buffer. -
buffer
is the buffer to query. -
pMemoryRequirements
is a pointer to a VkMemoryRequirements structure in which the memory requirements of the buffer object are returned.
To determine the memory requirements for an image resource which is not
created with the VK_IMAGE_CREATE_DISJOINT_BIT
flag set, call:
// Provided by VK_VERSION_1_0
void vkGetImageMemoryRequirements(
VkDevice device,
VkImage image,
VkMemoryRequirements* pMemoryRequirements);
-
device
is the logical device that owns the image. -
image
is the image to query. -
pMemoryRequirements
is a pointer to a VkMemoryRequirements structure in which the memory requirements of the image object are returned.
The VkMemoryRequirements
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkMemoryRequirements {
VkDeviceSize size;
VkDeviceSize alignment;
uint32_t memoryTypeBits;
} VkMemoryRequirements;
-
size
is the size, in bytes, of the memory allocation required for the resource. -
alignment
is the alignment, in bytes, of the offset within the allocation required for the resource. -
memoryTypeBits
is a bitmask and contains one bit set for every supported memory type for the resource. Biti
is set if and only if the memory typei
in theVkPhysicalDeviceMemoryProperties
structure for the physical device is supported for the resource.
The precise size of images that will be bound to external Android hardware
buffer memory is unknown until the memory has been imported or allocated, so
applications must not call vkGetImageMemoryRequirements or
vkGetImageMemoryRequirements2 with such an VkImage before it has
been bound to memory.
When importing Android hardware buffer memory, the allocationSize
can
be determined by calling vkGetAndroidHardwareBufferPropertiesANDROID.
When allocating new memory for a VkImage that can be exported to an
Android hardware buffer, the memory’s allocationSize
must be zero;
the actual size will be determined by the dedicated image’s parameters.
After the memory has been allocated, the amount of space allocated from the
memory’s heap can be obtained by getting the image’s memory requirements or
by calling vkGetAndroidHardwareBufferPropertiesANDROID with the
Android hardware buffer exported from the memory.
When allocating new memory for a VkBuffer that can be exported to an Android hardware buffer an application may still call vkGetBufferMemoryRequirements or vkGetBufferMemoryRequirements2 with VkBuffer before it has been bound to memory.
If the resource being queried was created with the
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT
,
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT
, or
VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT
external memory
handle type, the value of size
has no meaning and should be ignored.
The implementation guarantees certain properties about the memory requirements returned by vkGetBufferMemoryRequirements2, vkGetImageMemoryRequirements2, vkGetBufferMemoryRequirements and vkGetImageMemoryRequirements:
-
The
memoryTypeBits
member always contains at least one bit set. -
If
buffer
is aVkBuffer
not created with theVK_BUFFER_CREATE_SPARSE_BINDING_BIT
bit set, or ifimage
is linear image, then thememoryTypeBits
member always contains at least one bit set corresponding to aVkMemoryType
with apropertyFlags
that has both theVK_MEMORY_PROPERTY_HOST_VISIBLE_BIT
bit and theVK_MEMORY_PROPERTY_HOST_COHERENT_BIT
bit set. In other words, mappable coherent memory can always be attached to these objects. -
If
buffer
was created with VkExternalMemoryBufferCreateInfo::handleTypes
set to0
orimage
was created with VkExternalMemoryImageCreateInfo::handleTypes
set to0
, thememoryTypeBits
member always contains at least one bit set corresponding to aVkMemoryType
with apropertyFlags
that has theVK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT
bit set. -
The
memoryTypeBits
member is identical for allVkBuffer
objects created with the same value for theflags
andusage
members in the VkBufferCreateInfo structure and thehandleTypes
member of the VkExternalMemoryBufferCreateInfo structure passed tovkCreateBuffer
. Further, ifusage1
andusage2
of type VkBufferUsageFlags are such that the bits set inusage2
are a subset of the bits set inusage1
, and they have the sameflags
and VkExternalMemoryBufferCreateInfo::handleTypes
, then the bits set inmemoryTypeBits
returned forusage1
must be a subset of the bits set inmemoryTypeBits
returned forusage2
, for all values offlags
. -
The
alignment
member is a power of two. -
The
alignment
member is identical for allVkBuffer
objects created with the same combination of values for theusage
andflags
members in the VkBufferCreateInfo structure passed tovkCreateBuffer
. -
The
alignment
member satisfies the buffer descriptor offset alignment requirements associated with theVkBuffer
’susage
:-
If
usage
includedVK_BUFFER_USAGE_UNIFORM_TEXEL_BUFFER_BIT
orVK_BUFFER_USAGE_STORAGE_TEXEL_BUFFER_BIT
,alignment
must be an integer multiple ofVkPhysicalDeviceLimits
::minTexelBufferOffsetAlignment
. -
If
usage
includedVK_BUFFER_USAGE_UNIFORM_BUFFER_BIT
,alignment
must be an integer multiple ofVkPhysicalDeviceLimits
::minUniformBufferOffsetAlignment
. -
If
usage
includedVK_BUFFER_USAGE_STORAGE_BUFFER_BIT
,alignment
must be an integer multiple ofVkPhysicalDeviceLimits
::minStorageBufferOffsetAlignment
.
-
-
For images created with a color format, the
memoryTypeBits
member is identical for allVkImage
objects created with the same combination of values for thetiling
member, theVK_IMAGE_CREATE_SPARSE_BINDING_BIT
bit of theflags
member, theVK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT
bit of theflags
member,handleTypes
member of VkExternalMemoryImageCreateInfo, and theVK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT
of theusage
member in the VkImageCreateInfo structure passed tovkCreateImage
. -
For images created with a depth/stencil format, the
memoryTypeBits
member is identical for allVkImage
objects created with the same combination of values for theformat
member, thetiling
member, theVK_IMAGE_CREATE_SPARSE_BINDING_BIT
bit of theflags
member, theVK_IMAGE_CREATE_SPLIT_INSTANCE_BIND_REGIONS_BIT
bit of theflags
member,handleTypes
member of VkExternalMemoryImageCreateInfo, and theVK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT
of theusage
member in the VkImageCreateInfo structure passed tovkCreateImage
. -
If the memory requirements are for a
VkImage
, thememoryTypeBits
member must not refer to aVkMemoryType
with apropertyFlags
that has theVK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT
bit set if theimage
did not haveVK_IMAGE_USAGE_TRANSIENT_ATTACHMENT_BIT
bit set in theusage
member of the VkImageCreateInfo structure passed tovkCreateImage
. -
If the memory requirements are for a
VkBuffer
, thememoryTypeBits
member must not refer to aVkMemoryType
with apropertyFlags
that has theVK_MEMORY_PROPERTY_LAZILY_ALLOCATED_BIT
bit set.NoteThe implication of this requirement is that lazily allocated memory is disallowed for buffers in all cases.
-
The
size
member is identical for allVkBuffer
objects created with the same combination of creation parameters specified in VkBufferCreateInfo and itspNext
chain. -
The
size
member is identical for allVkImage
objects created with the same combination of creation parameters specified in VkImageCreateInfo and itspNext
chain.NoteThis, however, does not imply that they interpret the contents of the bound memory identically with each other. That additional guarantee, however, can be explicitly requested using
VK_IMAGE_CREATE_ALIAS_BIT
.
To determine the memory requirements for a buffer resource, call:
// Provided by VK_VERSION_1_1
void vkGetBufferMemoryRequirements2(
VkDevice device,
const VkBufferMemoryRequirementsInfo2* pInfo,
VkMemoryRequirements2* pMemoryRequirements);
or the equivalent command
// Provided by VK_KHR_get_memory_requirements2
void vkGetBufferMemoryRequirements2KHR(
VkDevice device,
const VkBufferMemoryRequirementsInfo2* pInfo,
VkMemoryRequirements2* pMemoryRequirements);
-
device
is the logical device that owns the buffer. -
pInfo
is a pointer to aVkBufferMemoryRequirementsInfo2
structure containing parameters required for the memory requirements query. -
pMemoryRequirements
is a pointer to a VkMemoryRequirements2 structure in which the memory requirements of the buffer object are returned.
The VkBufferMemoryRequirementsInfo2
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkBufferMemoryRequirementsInfo2 {
VkStructureType sType;
const void* pNext;
VkBuffer buffer;
} VkBufferMemoryRequirementsInfo2;
or the equivalent
// Provided by VK_KHR_get_memory_requirements2
typedef VkBufferMemoryRequirementsInfo2 VkBufferMemoryRequirementsInfo2KHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
buffer
is the buffer to query.
To determine the memory requirements for an image resource, call:
// Provided by VK_VERSION_1_1
void vkGetImageMemoryRequirements2(
VkDevice device,
const VkImageMemoryRequirementsInfo2* pInfo,
VkMemoryRequirements2* pMemoryRequirements);
or the equivalent command
// Provided by VK_KHR_get_memory_requirements2
void vkGetImageMemoryRequirements2KHR(
VkDevice device,
const VkImageMemoryRequirementsInfo2* pInfo,
VkMemoryRequirements2* pMemoryRequirements);
-
device
is the logical device that owns the image. -
pInfo
is a pointer to aVkImageMemoryRequirementsInfo2
structure containing parameters required for the memory requirements query. -
pMemoryRequirements
is a pointer to a VkMemoryRequirements2 structure in which the memory requirements of the image object are returned.
The VkImageMemoryRequirementsInfo2
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkImageMemoryRequirementsInfo2 {
VkStructureType sType;
const void* pNext;
VkImage image;
} VkImageMemoryRequirementsInfo2;
or the equivalent
// Provided by VK_KHR_get_memory_requirements2
typedef VkImageMemoryRequirementsInfo2 VkImageMemoryRequirementsInfo2KHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
image
is the image to query.
To determine the memory requirements for a plane of a disjoint image, add a
VkImagePlaneMemoryRequirementsInfo
structure to the pNext
chain
of the VkImageMemoryRequirementsInfo2
structure.
The VkImagePlaneMemoryRequirementsInfo
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkImagePlaneMemoryRequirementsInfo {
VkStructureType sType;
const void* pNext;
VkImageAspectFlagBits planeAspect;
} VkImagePlaneMemoryRequirementsInfo;
or the equivalent
// Provided by VK_KHR_sampler_ycbcr_conversion
typedef VkImagePlaneMemoryRequirementsInfo VkImagePlaneMemoryRequirementsInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
planeAspect
is the aspect corresponding to the image plane to query.
The VkMemoryRequirements2
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkMemoryRequirements2 {
VkStructureType sType;
void* pNext;
VkMemoryRequirements memoryRequirements;
} VkMemoryRequirements2;
or the equivalent
// Provided by VK_KHR_get_memory_requirements2, VK_NV_ray_tracing
typedef VkMemoryRequirements2 VkMemoryRequirements2KHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
memoryRequirements
is a VkMemoryRequirements structure describing the memory requirements of the resource.
To determine the dedicated allocation requirements of a buffer or image
resource, add a VkMemoryDedicatedRequirements structure to the
pNext
chain of the VkMemoryRequirements2 structure passed as the
pMemoryRequirements
parameter of vkGetBufferMemoryRequirements2
or vkGetImageMemoryRequirements2
.
The VkMemoryDedicatedRequirements
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkMemoryDedicatedRequirements {
VkStructureType sType;
void* pNext;
VkBool32 prefersDedicatedAllocation;
VkBool32 requiresDedicatedAllocation;
} VkMemoryDedicatedRequirements;
or the equivalent
// Provided by VK_KHR_dedicated_allocation
typedef VkMemoryDedicatedRequirements VkMemoryDedicatedRequirementsKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
prefersDedicatedAllocation
specifies that the implementation would prefer a dedicated allocation for this resource. The application is still free to suballocate the resource but it may get better performance if a dedicated allocation is used. -
requiresDedicatedAllocation
specifies that a dedicated allocation is required for this resource.
When the implementation sets requiresDedicatedAllocation
to
VK_TRUE
, it must also set prefersDedicatedAllocation
to
VK_TRUE
.
If the VkMemoryDedicatedRequirements
structure is included in the
pNext
chain of the VkMemoryRequirements2 structure passed as the
pMemoryRequirements
parameter of a
vkGetBufferMemoryRequirements2
call, requiresDedicatedAllocation
may be VK_TRUE
under one of the following conditions:
-
The
pNext
chain of VkBufferCreateInfo for the call tovkCreateBuffer
used to create the buffer being queried included a VkExternalMemoryBufferCreateInfo structure, and any of the handle types specified in VkExternalMemoryBufferCreateInfo::handleTypes
requires dedicated allocation, as reported by vkGetPhysicalDeviceExternalBufferProperties inVkExternalBufferProperties
::externalMemoryProperties.externalMemoryFeatures
, therequiresDedicatedAllocation
field will be set toVK_TRUE
.
In all other cases, requiresDedicatedAllocation
must be set to
VK_FALSE
by the implementation whenever a
VkMemoryDedicatedRequirements
structure is included in the pNext
chain of the VkMemoryRequirements2
structure passed to a call to
vkGetBufferMemoryRequirements2
.
If the VkMemoryDedicatedRequirements
structure is included in the
pNext
chain of the VkMemoryRequirements2
structure passed as the
pMemoryRequirements
parameter of a
vkGetBufferMemoryRequirements2
call and
VK_BUFFER_CREATE_SPARSE_BINDING_BIT
was set in
VkBufferCreateInfo::flags
when buffer
was created then the
implementation must set both prefersDedicatedAllocation
and
requiresDedicatedAllocation
to VK_FALSE
.
If the VkMemoryDedicatedRequirements
structure is included in the
pNext
chain of the VkMemoryRequirements2
structure passed as the
pMemoryRequirements
parameter of a vkGetImageMemoryRequirements2
call, requiresDedicatedAllocation
may be VK_TRUE
under one of
the following conditions:
-
The
pNext
chain of VkImageCreateInfo for the call tovkCreateImage
used to create the image being queried included a VkExternalMemoryImageCreateInfo structure, and any of the handle types specified in VkExternalMemoryImageCreateInfo::handleTypes
requires dedicated allocation, as reported by vkGetPhysicalDeviceImageFormatProperties2 inVkExternalImageFormatProperties
::externalMemoryProperties.externalMemoryFeatures
, therequiresDedicatedAllocation
field will be set toVK_TRUE
.
In all other cases, requiresDedicatedAllocation
must be set to
VK_FALSE
by the implementation whenever a
VkMemoryDedicatedRequirements
structure is included in the pNext
chain of the VkMemoryRequirements2
structure passed to a call to
vkGetImageMemoryRequirements2
.
If the VkMemoryDedicatedRequirements
structure is included in the
pNext
chain of the VkMemoryRequirements2
structure passed as the
pMemoryRequirements
parameter of a vkGetImageMemoryRequirements2
call and VK_IMAGE_CREATE_SPARSE_BINDING_BIT
was set in
VkImageCreateInfo::flags
when image
was created then the
implementation must set both prefersDedicatedAllocation
and
requiresDedicatedAllocation
to VK_FALSE
.
To attach memory to a buffer object, call:
// Provided by VK_VERSION_1_0
VkResult vkBindBufferMemory(
VkDevice device,
VkBuffer buffer,
VkDeviceMemory memory,
VkDeviceSize memoryOffset);
-
device
is the logical device that owns the buffer and memory. -
buffer
is the buffer to be attached to memory. -
memory
is a VkDeviceMemory object describing the device memory to attach. -
memoryOffset
is the start offset of the region ofmemory
which is to be bound to the buffer. The number of bytes returned in theVkMemoryRequirements
::size
member inmemory
, starting frommemoryOffset
bytes, will be bound to the specified buffer.
vkBindBufferMemory
is equivalent to passing the same parameters
through VkBindBufferMemoryInfo to vkBindBufferMemory2.
To attach memory to buffer objects for one or more buffers at a time, call:
// Provided by VK_VERSION_1_1
VkResult vkBindBufferMemory2(
VkDevice device,
uint32_t bindInfoCount,
const VkBindBufferMemoryInfo* pBindInfos);
or the equivalent command
// Provided by VK_KHR_bind_memory2
VkResult vkBindBufferMemory2KHR(
VkDevice device,
uint32_t bindInfoCount,
const VkBindBufferMemoryInfo* pBindInfos);
-
device
is the logical device that owns the buffers and memory. -
bindInfoCount
is the number of elements inpBindInfos
. -
pBindInfos
is a pointer to an array ofbindInfoCount
VkBindBufferMemoryInfo structures describing buffers and memory to bind.
On some implementations, it may be more efficient to batch memory bindings into a single command.
VkBindBufferMemoryInfo
contains members corresponding to the
parameters of vkBindBufferMemory.
The VkBindBufferMemoryInfo
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkBindBufferMemoryInfo {
VkStructureType sType;
const void* pNext;
VkBuffer buffer;
VkDeviceMemory memory;
VkDeviceSize memoryOffset;
} VkBindBufferMemoryInfo;
or the equivalent
// Provided by VK_KHR_bind_memory2
typedef VkBindBufferMemoryInfo VkBindBufferMemoryInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
buffer
is the buffer to be attached to memory. -
memory
is a VkDeviceMemory object describing the device memory to attach. -
memoryOffset
is the start offset of the region ofmemory
which is to be bound to the buffer. The number of bytes returned in theVkMemoryRequirements
::size
member inmemory
, starting frommemoryOffset
bytes, will be bound to the specified buffer.
// Provided by VK_VERSION_1_1
typedef struct VkBindBufferMemoryDeviceGroupInfo {
VkStructureType sType;
const void* pNext;
uint32_t deviceIndexCount;
const uint32_t* pDeviceIndices;
} VkBindBufferMemoryDeviceGroupInfo;
or the equivalent
// Provided by VK_KHR_device_group with VK_KHR_bind_memory2
typedef VkBindBufferMemoryDeviceGroupInfo VkBindBufferMemoryDeviceGroupInfoKHR;
If the pNext
list of VkBindBufferMemoryInfo includes a
VkBindBufferMemoryDeviceGroupInfo
structure, then that structure
determines how memory is bound to buffers across multiple devices in a
device group.
The VkBindBufferMemoryDeviceGroupInfo
structure is defined as:
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
deviceIndexCount
is the number of elements inpDeviceIndices
. -
pDeviceIndices
is a pointer to an array of device indices.
If deviceIndexCount
is greater than zero, then on device index i
the buffer is attached to the instance of memory
on the physical
device with device index pDeviceIndices[i].
If deviceIndexCount
is zero and memory
comes from a memory heap
with the VK_MEMORY_HEAP_MULTI_INSTANCE_BIT
bit set, then it is as if
pDeviceIndices
contains consecutive indices from zero to the number of
physical devices in the logical device, minus one.
In other words, by default each physical device attaches to its own instance
of memory
.
If deviceIndexCount
is zero and memory
comes from a memory heap
without the VK_MEMORY_HEAP_MULTI_INSTANCE_BIT
bit set, then it is as
if pDeviceIndices
contains an array of zeros.
In other words, by default each physical device attaches to instance zero.
To attach memory to a VkImage
object created without the
VK_IMAGE_CREATE_DISJOINT_BIT
set, call:
// Provided by VK_VERSION_1_0
VkResult vkBindImageMemory(
VkDevice device,
VkImage image,
VkDeviceMemory memory,
VkDeviceSize memoryOffset);
-
device
is the logical device that owns the image and memory. -
image
is the image. -
memory
is the VkDeviceMemory object describing the device memory to attach. -
memoryOffset
is the start offset of the region ofmemory
which is to be bound to the image. The number of bytes returned in theVkMemoryRequirements
::size
member inmemory
, starting frommemoryOffset
bytes, will be bound to the specified image.
vkBindImageMemory
is equivalent to passing the same parameters through
VkBindImageMemoryInfo to vkBindImageMemory2.
To attach memory to image objects for one or more images at a time, call:
// Provided by VK_VERSION_1_1
VkResult vkBindImageMemory2(
VkDevice device,
uint32_t bindInfoCount,
const VkBindImageMemoryInfo* pBindInfos);
or the equivalent command
// Provided by VK_KHR_bind_memory2
VkResult vkBindImageMemory2KHR(
VkDevice device,
uint32_t bindInfoCount,
const VkBindImageMemoryInfo* pBindInfos);
-
device
is the logical device that owns the images and memory. -
bindInfoCount
is the number of elements inpBindInfos
. -
pBindInfos
is a pointer to an array of VkBindImageMemoryInfo structures, describing images and memory to bind.
On some implementations, it may be more efficient to batch memory bindings into a single command.
VkBindImageMemoryInfo
contains members corresponding to the parameters
of vkBindImageMemory.
The VkBindImageMemoryInfo
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkBindImageMemoryInfo {
VkStructureType sType;
const void* pNext;
VkImage image;
VkDeviceMemory memory;
VkDeviceSize memoryOffset;
} VkBindImageMemoryInfo;
or the equivalent
// Provided by VK_KHR_bind_memory2
typedef VkBindImageMemoryInfo VkBindImageMemoryInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
image
is the image to be attached to memory. -
memory
is a VkDeviceMemory object describing the device memory to attach. -
memoryOffset
is the start offset of the region ofmemory
which is to be bound to the image. The number of bytes returned in theVkMemoryRequirements
::size
member inmemory
, starting frommemoryOffset
bytes, will be bound to the specified image.
// Provided by VK_VERSION_1_1
typedef struct VkBindImageMemoryDeviceGroupInfo {
VkStructureType sType;
const void* pNext;
uint32_t deviceIndexCount;
const uint32_t* pDeviceIndices;
uint32_t splitInstanceBindRegionCount;
const VkRect2D* pSplitInstanceBindRegions;
} VkBindImageMemoryDeviceGroupInfo;
or the equivalent
// Provided by VK_KHR_device_group with VK_KHR_bind_memory2
typedef VkBindImageMemoryDeviceGroupInfo VkBindImageMemoryDeviceGroupInfoKHR;
If the pNext
list of VkBindImageMemoryInfo includes a
VkBindImageMemoryDeviceGroupInfo
structure, then that structure
determines how memory is bound to images across multiple devices in a device
group.
The VkBindImageMemoryDeviceGroupInfo
structure is defined as:
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
deviceIndexCount
is the number of elements inpDeviceIndices
. -
pDeviceIndices
is a pointer to an array of device indices. -
splitInstanceBindRegionCount
is the number of elements inpSplitInstanceBindRegions
. -
pSplitInstanceBindRegions
is a pointer to an array of VkRect2D structures describing which regions of the image are attached to each instance of memory.
If deviceIndexCount
is greater than zero, then on device index i
image
is attached to the instance of the memory on the physical device
with device index pDeviceIndices[i].
Let N be the number of physical devices in the logical device.
If splitInstanceBindRegionCount
is greater than zero, then
pSplitInstanceBindRegions
is an array of N2 rectangles, where
the image region specified by the rectangle at element i*N+j in
resource instance i is bound to the memory instance j.
The blocks of the memory that are bound to each sparse image block region
use an offset in memory, relative to memoryOffset
, computed as if the
whole image were being bound to a contiguous range of memory.
In other words, horizontally adjacent image blocks use consecutive blocks of
memory, vertically adjacent image blocks are separated by the number of
bytes per block multiplied by the width in blocks of image
, and the
block at (0,0) corresponds to memory starting at memoryOffset
.
If splitInstanceBindRegionCount
and deviceIndexCount
are zero
and the memory comes from a memory heap with the
VK_MEMORY_HEAP_MULTI_INSTANCE_BIT
bit set, then it is as if
pDeviceIndices
contains consecutive indices from zero to the number of
physical devices in the logical device, minus one.
In other words, by default each physical device attaches to its own instance
of the memory.
If splitInstanceBindRegionCount
and deviceIndexCount
are zero
and the memory comes from a memory heap without the
VK_MEMORY_HEAP_MULTI_INSTANCE_BIT
bit set, then it is as if
pDeviceIndices
contains an array of zeros.
In other words, by default each physical device attaches to instance zero.
If the pNext
chain of VkBindImageMemoryInfo includes a
VkBindImageMemorySwapchainInfoKHR
structure, then that structure
includes a swapchain handle and image index indicating that the image will
be bound to memory from that swapchain.
The VkBindImageMemorySwapchainInfoKHR
structure is defined as:
// Provided by VK_KHR_swapchain with VK_VERSION_1_1, VK_KHR_device_group with VK_KHR_swapchain
typedef struct VkBindImageMemorySwapchainInfoKHR {
VkStructureType sType;
const void* pNext;
VkSwapchainKHR swapchain;
uint32_t imageIndex;
} VkBindImageMemorySwapchainInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
swapchain
is VK_NULL_HANDLE or a swapchain handle. -
imageIndex
is an image index withinswapchain
.
If swapchain
is not NULL
, the swapchain
and imageIndex
are used to determine the memory that the image is bound to, instead of
memory
and memoryOffset
.
Memory can be bound to a swapchain and use the pDeviceIndices
or
pSplitInstanceBindRegions
members of
VkBindImageMemoryDeviceGroupInfo.
In order to bind planes of a disjoint image, add a
VkBindImagePlaneMemoryInfo
structure to the pNext
chain of
VkBindImageMemoryInfo.
The VkBindImagePlaneMemoryInfo
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkBindImagePlaneMemoryInfo {
VkStructureType sType;
const void* pNext;
VkImageAspectFlagBits planeAspect;
} VkBindImagePlaneMemoryInfo;
or the equivalent
// Provided by VK_KHR_sampler_ycbcr_conversion
typedef VkBindImagePlaneMemoryInfo VkBindImagePlaneMemoryInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
planeAspect
is the aspect of the disjoint image plane to bind.
There is an implementation-dependent limit, bufferImageGranularity
,
which specifies a page-like granularity at which linear and non-linear
resources must be placed in adjacent memory locations to avoid aliasing.
Two resources which do not satisfy this granularity requirement are said to
alias.
bufferImageGranularity
is specified in bytes, and must be a power of
two.
Implementations which do not impose a granularity restriction may report a
bufferImageGranularity
value of one.
Note
Despite its name, |
Given resourceA at the lower memory offset and resourceB at the higher
memory offset in the same VkDeviceMemory
object, where one resource is
linear and the other is non-linear (as defined in the
Glossary), and the following:
resourceA.end = resourceA.memoryOffset + resourceA.size - 1
resourceA.endPage = resourceA.end & ~(bufferImageGranularity-1)
resourceB.start = resourceB.memoryOffset
resourceB.startPage = resourceB.start & ~(bufferImageGranularity-1)
The following property must hold:
resourceA.endPage < resourceB.startPage
That is, the end of the first resource (A) and the beginning of the second
resource (B) must be on separate “pages” of size
bufferImageGranularity
.
bufferImageGranularity
may be different than the physical page size
of the memory heap.
This restriction is only needed when a linear resource and a non-linear
resource are adjacent in memory and will be used simultaneously.
The memory ranges of adjacent resources can be closer than
bufferImageGranularity
, provided they meet the alignment
requirement for the objects in question.
Sparse block size in bytes and sparse image and buffer memory alignments
must all be multiples of the bufferImageGranularity
.
Therefore, memory bound to sparse resources naturally satisfies the
bufferImageGranularity
.
11.7. Resource Sharing Mode
Buffer and image objects are created with a sharing mode controlling how they can be accessed from queues. The supported sharing modes are:
// Provided by VK_VERSION_1_0
typedef enum VkSharingMode {
VK_SHARING_MODE_EXCLUSIVE = 0,
VK_SHARING_MODE_CONCURRENT = 1,
} VkSharingMode;
-
VK_SHARING_MODE_EXCLUSIVE
specifies that access to any range or image subresource of the object will be exclusive to a single queue family at a time. -
VK_SHARING_MODE_CONCURRENT
specifies that concurrent access to any range or image subresource of the object from multiple queue families is supported.
Note
|
Ranges of buffers and image subresources of image objects created using
VK_SHARING_MODE_EXCLUSIVE
must only be accessed by queues in the
queue family that has ownership of the resource.
Upon creation, such resources are not owned by any queue family; ownership
is implicitly acquired upon first use within a queue.
Once a resource using VK_SHARING_MODE_EXCLUSIVE
is owned by some queue
family, the application must perform a
queue family ownership transfer to make
the memory contents of a range or image subresource accessible to a
different queue family.
Note
Images still require a layout transition from
|
A queue family can take ownership of an image subresource or buffer range
of a resource created with VK_SHARING_MODE_EXCLUSIVE
, without an
ownership transfer, in the same way as for a resource that was just created;
however, taking ownership in this way has the effect that the contents of
the image subresource or buffer range are undefined.
Ranges of buffers and image subresources of image objects created using
VK_SHARING_MODE_CONCURRENT
must only be accessed by queues from the
queue families specified through the queueFamilyIndexCount
and
pQueueFamilyIndices
members of the corresponding create info
structures.
11.7.1. External Resource Sharing
Resources should only be accessed in the Vulkan instance that has exclusive
ownership of their underlying memory.
Only one Vulkan instance has exclusive ownership of a resource’s underlying
memory at a given time, regardless of whether the resource was created using
VK_SHARING_MODE_EXCLUSIVE
or VK_SHARING_MODE_CONCURRENT
.
Applications can transfer ownership of a resource’s underlying memory only
if the memory has been imported from or exported to another instance or
external API using external memory handles.
The semantics for transferring ownership outside of the instance are similar
to those used for transferring ownership of VK_SHARING_MODE_EXCLUSIVE
resources between queues, and is also accomplished using
VkBufferMemoryBarrier or VkImageMemoryBarrier operations.
Applications must
-
Release exclusive ownership from the source instance or API.
-
Ensure the release operation has completed using semaphores or fences.
-
Acquire exclusive ownership in the destination instance or API
Unlike queue ownership transfers, the destination instance or API is not
specified explicitly when releasing ownership, nor is the source instance or
API specified when acquiring ownership.
Instead, the image or memory barrier’s dstQueueFamilyIndex
or
srcQueueFamilyIndex
parameters are set to the reserved queue family
index VK_QUEUE_FAMILY_EXTERNAL
or VK_QUEUE_FAMILY_FOREIGN_EXT
to represent the external destination or source respectively.
Binding a resource to a memory object shared between multiple Vulkan
instances or other APIs does not change the ownership of the underlying
memory.
The first entity to access the resource implicitly acquires ownership.
Accessing a resource backed by memory that is owned by a particular instance
or API has the same semantics as accessing a VK_SHARING_MODE_EXCLUSIVE
resource, with one exception: Implementations must ensure layout
transitions performed on one member of a set of identical subresources of
identical images that alias the same range of an underlying memory object
affect the layout of all the subresources in the set.
As a corollary, writes to any image subresources in such a set must not
make the contents of memory used by other subresources in the set
undefined.
An application can define the content of a subresource of one image by
performing device writes to an identical subresource of another image
provided both images are bound to the same region of external memory.
Applications may also add resources to such a set after the content of the
existing set members has been defined without making the content undefined
by creating a new image with the initial layout
VK_IMAGE_LAYOUT_UNDEFINED
and binding it to the same region of
external memory as the existing images.
Note
Because layout transitions apply to all identical images aliasing the same region of external memory, the actual layout of the memory backing a new image as well as an existing image with defined content will not be undefined. Such an image is not usable until it acquires ownership of its memory from the existing owner. Therefore, the layout specified as part of this transition will be the true initial layout of the image. The undefined layout specified when creating it is a placeholder to simplify valid usage requirements. |
11.8. Memory Aliasing
A range of a VkDeviceMemory
allocation is aliased if it is bound to
multiple resources simultaneously, as described below, via
vkBindImageMemory, vkBindBufferMemory,
vkBindAccelerationStructureMemoryKHR,
vkBindAccelerationStructureMemoryNV,
via sparse memory bindings, or by binding
the memory to resources in multiple Vulkan instances or external APIs using
external memory handle export and import mechanisms.
Consider two resources, resourceA and resourceB, bound respectively to
memory rangeA and rangeB.
Let paddedRangeA and paddedRangeB be, respectively, rangeA and
rangeB aligned to bufferImageGranularity
.
If the resources are both linear or both non-linear (as defined in the
Glossary), then the resources alias the
memory in the intersection of rangeA and rangeB.
If one resource is linear and the other is non-linear, then the resources
alias the memory in the intersection of paddedRangeA and paddedRangeB.
Applications can alias memory, but use of multiple aliases is subject to several constraints.
Note
Memory aliasing can be useful to reduce the total device memory footprint of an application, if some large resources are used for disjoint periods of time. |
When a non-linear,
non-VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
image is bound to an aliased
range, all image subresources of the image overlap the range.
When a linear image is bound to an aliased range, the image subresources
that (according to the image’s advertised layout) include bytes from the
aliased range overlap the range.
When a VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
image has sparse image
blocks bound to an aliased range, only image subresources including those
sparse image blocks overlap the range, and when the memory bound to the
image’s mip tail overlaps an aliased range all image subresources in the mip
tail overlap the range.
Buffers, and linear image subresources in either the
VK_IMAGE_LAYOUT_PREINITIALIZED
or VK_IMAGE_LAYOUT_GENERAL
layouts, are host-accessible subresources.
That is, the host has a well-defined addressing scheme to interpret the
contents, and thus the layout of the data in memory can be consistently
interpreted across aliases if each of those aliases is a host-accessible
subresource.
Non-linear images, and linear image subresources in other layouts, are not
host-accessible.
If two aliases are both host-accessible, then they interpret the contents of the memory in consistent ways, and data written to one alias can be read by the other alias.
If two aliases are both images that were created with identical creation
parameters, both were created with the VK_IMAGE_CREATE_ALIAS_BIT
flag
set, and both are bound identically to memory
except for VkBindImageMemoryDeviceGroupInfo::pDeviceIndices
and
VkBindImageMemoryDeviceGroupInfo::pSplitInstanceBindRegions
,
then they interpret the contents of the memory in consistent ways, and data
written to one alias can be read by the other alias.
Additionally, if an invididual plane of a multi-planar image and a single-plane image alias the same memory, then they also interpret the contents of the memory in consistent ways under the same conditions, but with the following modifications:
-
Both must have been created with the
VK_IMAGE_CREATE_DISJOINT_BIT
flag. -
The single-plane image must have a VkFormat that is equivalent to that of the multi-planar image’s individual plane.
-
The single-plane image and the individual plane of the multi-planar image must be bound identically to memory except for VkBindImageMemoryDeviceGroupInfo::
pDeviceIndices
and VkBindImageMemoryDeviceGroupInfo::pSplitInstanceBindRegions
. -
The
width
andheight
of the single-plane image are derived from the multi-planar image’s dimensions in the manner listed for plane compatibility for the aliased plane. -
If either image’s
tiling
isVK_IMAGE_TILING_DRM_FORMAT_MODIFIER_EXT
, then both images must be linear. -
All other creation parameters must be identical
Aliases created by binding the same memory to resources in multiple Vulkan instances or external APIs using external memory handle export and import mechanisms interpret the contents of the memory in consistent ways, and data written to one alias can be read by the other alias.
Otherwise, the aliases interpret the contents of the memory differently, and writes via one alias make the contents of memory partially or completely undefined to the other alias. If the first alias is a host-accessible subresource, then the bytes affected are those written by the memory operations according to its addressing scheme. If the first alias is not host-accessible, then the bytes affected are those overlapped by the image subresources that were written. If the second alias is a host-accessible subresource, the affected bytes become undefined. If the second alias is a not host-accessible, all sparse image blocks (for sparse partially-resident images) or all image subresources (for non-sparse image and fully resident sparse images) that overlap the affected bytes become undefined.
If any image subresources are made undefined due to writes to an alias,
then each of those image subresources must have its layout transitioned
from VK_IMAGE_LAYOUT_UNDEFINED
to a valid layout before it is used, or
from VK_IMAGE_LAYOUT_PREINITIALIZED
if the memory has been written by
the host.
If any sparse blocks of a sparse image have been made undefined, then only
the image subresources containing them must be transitioned.
Use of an overlapping range by two aliases must be separated by a memory dependency using the appropriate access types if at least one of those uses performs writes, whether the aliases interpret memory consistently or not. If buffer or image memory barriers are used, the scope of the barrier must contain the entire range and/or set of image subresources that overlap.
If two aliasing image views are used in the same framebuffer, then the
render pass must declare the attachments using the
VK_ATTACHMENT_DESCRIPTION_MAY_ALIAS_BIT
, and
follow the other rules listed in that section.
Note
Memory recycled via an application suballocator (i.e. without freeing and reallocating the memory objects) is not substantially different from memory aliasing. However, a suballocator usually waits on a fence before recycling a region of memory, and signaling a fence involves sufficient implicit dependencies to satisfy all the above requirements. |
11.9. Acceleration Structures
Acceleration structures are an opaque structure that is built by the implementation to more efficiently perform spatial queries on the provided geometric data. For this extension, an acceleration structure is either a top-level acceleration structure containing a set of bottom-level acceleration structures or a bottom-level acceleration structure containing either a set of axis-aligned bounding boxes for custom geometry or a set of triangles.
Each instance in the top-level acceleration structure contains a reference to a bottom-level acceleration structure as well as an instance transform plus information required to index into the shader bindings. The top-level acceleration structure is what is bound to the acceleration descriptor to trace inside the shader in the ray tracing pipeline.
Acceleration structures are represented by VkAccelerationStructureKHR
handles:
// Provided by VK_KHR_ray_tracing
VK_DEFINE_NON_DISPATCHABLE_HANDLE(VkAccelerationStructureKHR)
or the equivalent
// Provided by VK_NV_ray_tracing
typedef VkAccelerationStructureKHR VkAccelerationStructureNV;
To create acceleration structures, call:
// Provided by VK_NV_ray_tracing
VkResult vkCreateAccelerationStructureNV(
VkDevice device,
const VkAccelerationStructureCreateInfoNV* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkAccelerationStructureNV* pAccelerationStructure);
-
device
is the logical device that creates the buffer object. -
pCreateInfo
is a pointer to a VkAccelerationStructureCreateInfoNV structure containing parameters affecting creation of the acceleration structure. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter. -
pAccelerationStructure
is a pointer to a VkAccelerationStructureNV handle in which the resulting acceleration structure object is returned.
Similar to other objects in Vulkan, the acceleration structure creation
merely creates an object with a specific “shape” as specified by the
information in VkAccelerationStructureInfoNV and compactedSize
in pCreateInfo
.
Populating the data in the object after allocating and binding memory is
done with vkCmdBuildAccelerationStructureNV and
vkCmdCopyAccelerationStructureNV.
Acceleration structure creation uses the count and type information from the geometries, but does not use the data references in the structures.
The VkAccelerationStructureCreateInfoNV
structure is defined as:
// Provided by VK_NV_ray_tracing
typedef struct VkAccelerationStructureCreateInfoNV {
VkStructureType sType;
const void* pNext;
VkDeviceSize compactedSize;
VkAccelerationStructureInfoNV info;
} VkAccelerationStructureCreateInfoNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
compactedSize
is the size from the result of vkCmdWriteAccelerationStructuresPropertiesNV if this acceleration structure is going to be the target of a compacting copy. -
info
is the VkAccelerationStructureInfoNV structure specifying further parameters of the created acceleration structure.
The VkAccelerationStructureInfoNV
structure is defined as:
// Provided by VK_NV_ray_tracing
typedef struct VkAccelerationStructureInfoNV {
VkStructureType sType;
const void* pNext;
VkAccelerationStructureTypeNV type;
VkBuildAccelerationStructureFlagsNV flags;
uint32_t instanceCount;
uint32_t geometryCount;
const VkGeometryNV* pGeometries;
} VkAccelerationStructureInfoNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
type
is a VkAccelerationStructureTypeNV value specifying the type of acceleration structure that will be created. -
flags
is a bitmask of VkBuildAccelerationStructureFlagBitsNV specifying additional parameters of the acceleration structure. -
instanceCount
specifies the number of instances that will be in the new acceleration structure. -
geometryCount
specifies the number of geometries that will be in the new acceleration structure. -
pGeometries
is a pointer to an array ofgeometryCount
VkGeometryNV structures containing the scene data being passed into the acceleration structure.
VkAccelerationStructureInfoNV
contains information that is used both
for acceleration structure creation with
vkCreateAccelerationStructureNV and in combination with the actual
geometric data to build the acceleration structure with
vkCmdBuildAccelerationStructureNV.
To create an acceleration structure, call:
// Provided by VK_KHR_ray_tracing
VkResult vkCreateAccelerationStructureKHR(
VkDevice device,
const VkAccelerationStructureCreateInfoKHR* pCreateInfo,
const VkAllocationCallbacks* pAllocator,
VkAccelerationStructureKHR* pAccelerationStructure);
-
device
is the logical device that creates the buffer object. -
pCreateInfo
is a pointer to a VkAccelerationStructureCreateInfoKHR structure containing parameters affecting creation of the acceleration structure. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter. -
pAccelerationStructure
is a pointer to aVkAccelerationStructureKHR
handle in which the resulting acceleration structure object is returned.
Similar to other objects in Vulkan, the acceleration structure creation merely creates an object with a specific “shape”. The type and quantity of geometry that can be built into an acceleration structure is determined by the parameters of VkAccelerationStructureCreateInfoKHR.
Populating the data in the object after allocating and binding memory is done with commands such as vkCmdBuildAccelerationStructureKHR, vkBuildAccelerationStructureKHR, vkCmdCopyAccelerationStructureKHR, and vkCopyAccelerationStructureKHR.
The input buffers passed to acceleration structure build commands will be referenced by the implementation for the duration of the command. After the command completes, the acceleration structure may hold a reference to any acceleration structure specified by an active instance contained therein. Apart from this referencing, acceleration structures must be fully self-contained. The application may re-use or free any memory which was used by the command as an input or as scratch without affecting the results of ray traversal.
The VkAccelerationStructureCreateInfoKHR
structure is defined as:
// Provided by VK_KHR_ray_tracing
typedef struct VkAccelerationStructureCreateInfoKHR {
VkStructureType sType;
const void* pNext;
VkDeviceSize compactedSize;
VkAccelerationStructureTypeKHR type;
VkBuildAccelerationStructureFlagsKHR flags;
uint32_t maxGeometryCount;
const VkAccelerationStructureCreateGeometryTypeInfoKHR* pGeometryInfos;
VkDeviceAddress deviceAddress;
} VkAccelerationStructureCreateInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
compactedSize
is the size from the result of vkCmdWriteAccelerationStructuresPropertiesKHR if this acceleration structure is going to be the target of a compacting copy. -
type
is a VkAccelerationStructureTypeKHR value specifying the type of acceleration structure that will be created. -
flags
is a bitmask of VkBuildAccelerationStructureFlagBitsKHR specifying additional parameters of the acceleration structure. -
maxGeometryCount
specifies the number of geometries that will be in the new acceleration structure. -
pGeometryInfos
is an array ofmaxGeometryCount
VkAccelerationStructureCreateGeometryTypeInfoKHR structures, which describe the maximum size and format of the data that will be built into the acceleration structure. -
deviceAddress
is the device address requested for the acceleration structure if therayTracingAccelerationStructureCaptureReplay
feature is being used.
If deviceAddress
is zero, no specific address is requested.
If deviceAddress
is not zero, deviceAddress
must be an address
retrieved from an identically created acceleration structure on the same
implementation.
The acceleration structure must also be bound to an identically created
VkDeviceMemory
object.
Apps should avoid creating acceleration structures with app-provided
addresses and implementation-provided addresses in the same process, to
reduce the likelihood of VK_ERROR_INVALID_OPAQUE_CAPTURE_ADDRESS_KHR
errors.
The VkAccelerationStructureCreateGeometryTypeInfoKHR
structure
specifies the shape of geometries that will be built into an acceleration
structure and is defined as:
// Provided by VK_KHR_ray_tracing
typedef struct VkAccelerationStructureCreateGeometryTypeInfoKHR {
VkStructureType sType;
const void* pNext;
VkGeometryTypeKHR geometryType;
uint32_t maxPrimitiveCount;
VkIndexType indexType;
uint32_t maxVertexCount;
VkFormat vertexFormat;
VkBool32 allowsTransforms;
} VkAccelerationStructureCreateGeometryTypeInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
geometryType
is a VkGeometryTypeKHR that describes the type of an acceleration structure geometry. -
maxPrimitiveCount
describes the maximum number of primitives that can be built into an acceleration structure geometry. -
indexType
is a VkIndexType that describes the index type used to build this geometry whengeometryType
isVK_GEOMETRY_TYPE_TRIANGLES_KHR
. -
maxVertexCount
describes the maximum vertex count that can be used to build an acceleration structure geometry whengeometryType
isVK_GEOMETRY_TYPE_TRIANGLES_KHR
. -
vertexFormat
is a VkFormat that describes the vertex format used to build this geometry whengeometryType
isVK_GEOMETRY_TYPE_TRIANGLES_KHR
. -
allowsTransforms
indicates whether transform data can be used by this acceleration structure or not, whengeometryType
isVK_GEOMETRY_TYPE_TRIANGLES_KHR
.
When geometryType
is VK_GEOMETRY_TYPE_TRIANGLES_KHR
:
-
if
indexType
isVK_INDEX_TYPE_NONE_KHR
, then this structure describes a set of triangles. -
if
indexType
is notVK_INDEX_TYPE_NONE_KHR
, then this structure describes a set of indexed triangles.
Values which can be set in
VkAccelerationStructureCreateInfoKHR::type
or
VkAccelerationStructureInfoNV::type
specifying the type of acceleration structure, are:
// Provided by VK_KHR_ray_tracing
typedef enum VkAccelerationStructureTypeKHR {
VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR = 0,
VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR = 1,
// Provided by VK_NV_ray_tracing
VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_NV = VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR,
// Provided by VK_NV_ray_tracing
VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_NV = VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR,
} VkAccelerationStructureTypeKHR;
or the equivalent
// Provided by VK_NV_ray_tracing
typedef VkAccelerationStructureTypeKHR VkAccelerationStructureTypeNV;
-
VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_KHR
is a top-level acceleration structure containing instance data referring to bottom-level acceleration structures. -
VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_KHR
is a bottom-level acceleration structure containing the AABBs or geometry to be intersected.
Bits which can be set in
VkAccelerationStructureCreateInfoKHR::flags
or
VkAccelerationStructureInfoNV::flags
specifying additional parameters for acceleration structure builds, are:
// Provided by VK_KHR_ray_tracing
typedef enum VkBuildAccelerationStructureFlagBitsKHR {
VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR = 0x00000001,
VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR = 0x00000002,
VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR = 0x00000004,
VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR = 0x00000008,
VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_KHR = 0x00000010,
// Provided by VK_NV_ray_tracing
VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR,
// Provided by VK_NV_ray_tracing
VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR,
// Provided by VK_NV_ray_tracing
VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR,
// Provided by VK_NV_ray_tracing
VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR,
// Provided by VK_NV_ray_tracing
VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_NV = VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_KHR,
} VkBuildAccelerationStructureFlagBitsKHR;
or the equivalent
// Provided by VK_NV_ray_tracing
typedef VkBuildAccelerationStructureFlagBitsKHR VkBuildAccelerationStructureFlagBitsNV;
-
VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR
indicates that the specified acceleration structure can be updated withupdate
ofVK_TRUE
in vkCmdBuildAccelerationStructureKHR or vkCmdBuildAccelerationStructureNV . -
VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR
indicates that the specified acceleration structure can act as the source for a copy acceleration structure command withmode
ofVK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR
to produce a compacted acceleration structure. -
VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR
indicates that the given acceleration structure build should prioritize trace performance over build time. -
VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR
indicates that the given acceleration structure build should prioritize build time over trace performance. -
VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_KHR
indicates that this acceleration structure should minimize the size of the scratch memory and the final result build, potentially at the expense of build time or trace performance.
Note
|
// Provided by VK_KHR_ray_tracing
typedef VkFlags VkBuildAccelerationStructureFlagsKHR;
or the equivalent
// Provided by VK_NV_ray_tracing
typedef VkBuildAccelerationStructureFlagsKHR VkBuildAccelerationStructureFlagsNV;
VkBuildAccelerationStructureFlagsKHR
is a bitmask type for setting a
mask of zero or more VkBuildAccelerationStructureFlagBitsKHR.
The VkGeometryNV
structure describes geometry in a bottom-level
acceleration structure and is defined as:
// Provided by VK_NV_ray_tracing
typedef struct VkGeometryNV {
VkStructureType sType;
const void* pNext;
VkGeometryTypeKHR geometryType;
VkGeometryDataNV geometry;
VkGeometryFlagsKHR flags;
} VkGeometryNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
geometryType
specifies the VkGeometryTypeKHR which this geometry refers to. -
geometry
contains the geometry data as described in VkGeometryDataNV. -
flags
has VkGeometryFlagBitsKHR describing options for this geometry.
Geometry types are specified by VkGeometryTypeKHR, which takes values:
// Provided by VK_KHR_ray_tracing
typedef enum VkGeometryTypeKHR {
VK_GEOMETRY_TYPE_TRIANGLES_KHR = 0,
VK_GEOMETRY_TYPE_AABBS_KHR = 1,
// Provided by VK_KHR_ray_tracing
VK_GEOMETRY_TYPE_INSTANCES_KHR = 1000150000,
// Provided by VK_NV_ray_tracing
VK_GEOMETRY_TYPE_TRIANGLES_NV = VK_GEOMETRY_TYPE_TRIANGLES_KHR,
// Provided by VK_NV_ray_tracing
VK_GEOMETRY_TYPE_AABBS_NV = VK_GEOMETRY_TYPE_AABBS_KHR,
} VkGeometryTypeKHR;
or the equivalent
// Provided by VK_NV_ray_tracing
typedef VkGeometryTypeKHR VkGeometryTypeNV;
-
VK_GEOMETRY_TYPE_TRIANGLES_KHR
specifies a geometry type consisting of triangles. -
VK_GEOMETRY_TYPE_AABBS_KHR
specifies a geometry type consisting of axis-aligned bounding boxes. -
VK_GEOMETRY_TYPE_INSTANCES_KHR
specifies a geometry type consisting of acceleration structure instances.
Bits specifying additional parameters for geometries in acceleration structure builds, are:
// Provided by VK_KHR_ray_tracing
typedef enum VkGeometryFlagBitsKHR {
VK_GEOMETRY_OPAQUE_BIT_KHR = 0x00000001,
VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_KHR = 0x00000002,
// Provided by VK_NV_ray_tracing
VK_GEOMETRY_OPAQUE_BIT_NV = VK_GEOMETRY_OPAQUE_BIT_KHR,
// Provided by VK_NV_ray_tracing
VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_NV = VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_KHR,
} VkGeometryFlagBitsKHR;
or the equivalent
// Provided by VK_NV_ray_tracing
typedef VkGeometryFlagBitsKHR VkGeometryFlagBitsNV;
-
VK_GEOMETRY_OPAQUE_BIT_KHR
indicates that this geometry does not invoke the any-hit shaders even if present in a hit group. -
VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_KHR
indicates that the implementation must only call the any-hit shader a single time for each primitive in this geometry. If this bit is absent an implementation may invoke the any-hit shader more than once for this geometry.
// Provided by VK_KHR_ray_tracing
typedef VkFlags VkGeometryFlagsKHR;
or the equivalent
// Provided by VK_NV_ray_tracing
typedef VkGeometryFlagsKHR VkGeometryFlagsNV;
VkGeometryFlagsKHR
is a bitmask type for setting a mask of zero or
more VkGeometryFlagBitsKHR.
The VkGeometryDataNV
structure specifes geometry in a bottom-level
acceleration structure and is defined as:
// Provided by VK_NV_ray_tracing
typedef struct VkGeometryDataNV {
VkGeometryTrianglesNV triangles;
VkGeometryAABBNV aabbs;
} VkGeometryDataNV;
-
triangles
contains triangle data if VkGeometryNV::geometryType
isVK_GEOMETRY_TYPE_TRIANGLES_NV
. -
aabbs
contains axis-aligned bounding box data if VkGeometryNV::geometryType
isVK_GEOMETRY_TYPE_AABBS_NV
.
The VkGeometryTrianglesNV
structure specifies triangle geometry in a
bottom-level acceleration structure and is defined as:
// Provided by VK_NV_ray_tracing
typedef struct VkGeometryTrianglesNV {
VkStructureType sType;
const void* pNext;
VkBuffer vertexData;
VkDeviceSize vertexOffset;
uint32_t vertexCount;
VkDeviceSize vertexStride;
VkFormat vertexFormat;
VkBuffer indexData;
VkDeviceSize indexOffset;
uint32_t indexCount;
VkIndexType indexType;
VkBuffer transformData;
VkDeviceSize transformOffset;
} VkGeometryTrianglesNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
vertexData
is the buffer containing vertex data for this geometry. -
vertexOffset
is the offset in bytes withinvertexData
containing vertex data for this geometry. -
vertexCount
is the number of valid vertices. -
vertexStride
is the stride in bytes between each vertex. -
vertexFormat
is a VkFormat describing the format of each vertex element. -
indexData
is the buffer containing index data for this geometry. -
indexOffset
is the offset in bytes withinindexData
containing index data for this geometry. -
indexCount
is the number of indices to include in this geometry. -
indexType
is a VkIndexType describing the format of each index. -
transformData
is an optional buffer containing an VkTransformMatrixNV structure defining a transformation to be applied to this geometry. -
transformOffset
is the offset in bytes intransformData
of the transform information described above.
If indexType
is VK_INDEX_TYPE_NONE_NV
, then this structure
describes a set of triangles determined by vertexCount
.
Otherwise, this structure describes a set of indexed triangles determined by
indexCount
.
The VkGeometryAABBNV
structure specifies axis-aligned bounding box
geometry in a bottom-level acceleration structure, and is defined as:
// Provided by VK_NV_ray_tracing
typedef struct VkGeometryAABBNV {
VkStructureType sType;
const void* pNext;
VkBuffer aabbData;
uint32_t numAABBs;
uint32_t stride;
VkDeviceSize offset;
} VkGeometryAABBNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
aabbData
is the buffer containing axis-aligned bounding box data. -
numAABBs
is the number of AABBs in this geometry. -
stride
is the stride in bytes between AABBs inaabbData
. -
offset
is the offset in bytes of the first AABB inaabbData
.
The AABB data in memory is six 32-bit floats consisting of the minimum x, y, and z values followed by the maximum x, y, and z values.
To destroy an acceleration structure, call:
// Provided by VK_KHR_ray_tracing
void vkDestroyAccelerationStructureKHR(
VkDevice device,
VkAccelerationStructureKHR accelerationStructure,
const VkAllocationCallbacks* pAllocator);
or the equivalent command
// Provided by VK_NV_ray_tracing
void vkDestroyAccelerationStructureNV(
VkDevice device,
VkAccelerationStructureKHR accelerationStructure,
const VkAllocationCallbacks* pAllocator);
-
device
is the logical device that destroys the buffer. -
accelerationStructure
is the acceleration structure to destroy. -
pAllocator
controls host memory allocation as described in the Memory Allocation chapter.
An acceleration structure has memory requirements for the structure object itself, scratch space for the build, and scratch space for the update.
Scratch space is allocated as a VkBuffer
, so for
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_NV
and
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_NV
the pMemoryRequirements->alignment
and
pMemoryRequirements->memoryTypeBits
values returned by this call must
be filled with zero, and should be ignored by the application.
To query the memory requirements call:
// Provided by VK_NV_ray_tracing
void vkGetAccelerationStructureMemoryRequirementsNV(
VkDevice device,
const VkAccelerationStructureMemoryRequirementsInfoNV* pInfo,
VkMemoryRequirements2KHR* pMemoryRequirements);
-
device
is the logical device on which the acceleration structure was created. -
pInfo
specifies the acceleration structure to get memory requirements for. -
pMemoryRequirements
returns the requested acceleration structure memory requirements.
The VkAccelerationStructureMemoryRequirementsInfoNV
structure is
defined as:
// Provided by VK_NV_ray_tracing
typedef struct VkAccelerationStructureMemoryRequirementsInfoNV {
VkStructureType sType;
const void* pNext;
VkAccelerationStructureMemoryRequirementsTypeNV type;
VkAccelerationStructureNV accelerationStructure;
} VkAccelerationStructureMemoryRequirementsInfoNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
type
selects the type of memory requirement being queried.VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_NV
returns the memory requirements for the object itself.VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_NV
returns the memory requirements for the scratch memory when doing a build.VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_NV
returns the memory requirements for the scratch memory when doing an update. -
accelerationStructure
is the acceleration structure to be queried for memory requirements.
An acceleration structure has memory requirements for the structure object itself, scratch space for the build, and scratch space for the update.
Scratch space is allocated as a VkBuffer
, so for
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR
and
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR
the pMemoryRequirements->alignment
and
pMemoryRequirements->memoryTypeBits
values returned by this call must
be filled with zero, and should be ignored by the application.
To query the memory requirements call:
// Provided by VK_KHR_ray_tracing
void vkGetAccelerationStructureMemoryRequirementsKHR(
VkDevice device,
const VkAccelerationStructureMemoryRequirementsInfoKHR* pInfo,
VkMemoryRequirements2* pMemoryRequirements);
-
device
is the logical device on which the acceleration structure was created. -
pInfo
specifies the acceleration structure to get memory requirements for. -
pMemoryRequirements
returns the requested acceleration structure memory requirements.
The VkAccelerationStructureMemoryRequirementsInfoKHR
structure is
defined as:
// Provided by VK_KHR_ray_tracing
typedef struct VkAccelerationStructureMemoryRequirementsInfoKHR {
VkStructureType sType;
const void* pNext;
VkAccelerationStructureMemoryRequirementsTypeKHR type;
VkAccelerationStructureBuildTypeKHR buildType;
VkAccelerationStructureKHR accelerationStructure;
} VkAccelerationStructureMemoryRequirementsInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
buildType
selects the build types whose memory requirements are being queried. -
type
selects the type of memory requirement being queried.VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR
returns the memory requirements for the object itself.VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR
returns the memory requirements for the scratch memory when doing a build.VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR
returns the memory requirements for the scratch memory when doing an update. -
accelerationStructure
is the acceleration structure to be queried for memory requirements.
Possible values of type
in
VkAccelerationStructureMemoryRequirementsInfoKHR
are:
// Provided by VK_KHR_ray_tracing
typedef enum VkAccelerationStructureMemoryRequirementsTypeKHR {
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR = 0,
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR = 1,
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR = 2,
// Provided by VK_NV_ray_tracing
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_NV = VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR,
// Provided by VK_NV_ray_tracing
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_NV = VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR,
// Provided by VK_NV_ray_tracing
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_NV = VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR,
} VkAccelerationStructureMemoryRequirementsTypeKHR;
or the equivalent
// Provided by VK_NV_ray_tracing
typedef VkAccelerationStructureMemoryRequirementsTypeKHR VkAccelerationStructureMemoryRequirementsTypeNV;
-
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR
requests the memory requirement for theVkAccelerationStructureKHR
backing store. -
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_BUILD_SCRATCH_KHR
requests the memory requirement for scratch space during the initial build. -
VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_UPDATE_SCRATCH_KHR
requests the memory requirement for scratch space during an update.
Possible values of buildType
in
VkAccelerationStructureMemoryRequirementsInfoKHR
are:
// Provided by VK_KHR_ray_tracing
typedef enum VkAccelerationStructureBuildTypeKHR {
VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_KHR = 0,
VK_ACCELERATION_STRUCTURE_BUILD_TYPE_DEVICE_KHR = 1,
VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_OR_DEVICE_KHR = 2,
} VkAccelerationStructureBuildTypeKHR;
-
VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_KHR
requests the memory requirement for operations performed by the host. -
VK_ACCELERATION_STRUCTURE_BUILD_TYPE_DEVICE_KHR
requests the memory requirement for operations performed by the device. -
VK_ACCELERATION_STRUCTURE_BUILD_TYPE_HOST_OR_DEVICE_KHR
requests the memory requirement for operations performed by either the host, or the device.
The implementation guarantees certain properties about the memory
requirements returned by
vkGetAccelerationStructureMemoryRequirementsKHR called with a
type
of VK_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_TYPE_OBJECT_KHR:
-
The
memoryTypeBits
member always contains at least one bit set. -
The
memoryTypeBits
member is identical for allVkAccelerationStructureKHR
objects created with the same value for thetype
andflags
members in theVkAccelerationStructureCreateInfoKHR
structure passed tovkCreateAccelerationStructureKHR
and with the same value forbuildType
inVkAccelerationStructureMemoryRequirementsInfoKHR
passed to vkGetAccelerationStructureMemoryRequirementsKHR.
To attach memory to one or more acceleration structures at a time, call:
// Provided by VK_KHR_ray_tracing
VkResult vkBindAccelerationStructureMemoryKHR(
VkDevice device,
uint32_t bindInfoCount,
const VkBindAccelerationStructureMemoryInfoKHR* pBindInfos);
or the equivalent command
// Provided by VK_NV_ray_tracing
VkResult vkBindAccelerationStructureMemoryNV(
VkDevice device,
uint32_t bindInfoCount,
const VkBindAccelerationStructureMemoryInfoKHR* pBindInfos);
-
device
is the logical device that owns the acceleration structures and memory. -
bindInfoCount
is the number of elements inpBindInfos
. -
pBindInfos
is a pointer to an array of VkBindAccelerationStructureMemoryInfoKHR structures describing acceleration structures and memory to bind.
The VkBindAccelerationStructureMemoryInfoKHR
structure is defined as:
// Provided by VK_KHR_ray_tracing
typedef struct VkBindAccelerationStructureMemoryInfoKHR {
VkStructureType sType;
const void* pNext;
VkAccelerationStructureKHR accelerationStructure;
VkDeviceMemory memory;
VkDeviceSize memoryOffset;
uint32_t deviceIndexCount;
const uint32_t* pDeviceIndices;
} VkBindAccelerationStructureMemoryInfoKHR;
or the equivalent
// Provided by VK_NV_ray_tracing
typedef VkBindAccelerationStructureMemoryInfoKHR VkBindAccelerationStructureMemoryInfoNV;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
accelerationStructure
is the acceleration structure to be attached to memory. -
memory
is aVkDeviceMemory
object describing the device memory to attach. -
memoryOffset
is the start offset of the region of memory that is to be bound to the acceleration structure. The number of bytes returned in the VkMemoryRequirements::size
member inmemory
, starting frommemoryOffset
bytes, will be bound to the specified acceleration structure. -
deviceIndexCount
is the number of elements inpDeviceIndices
. -
pDeviceIndices
is a pointer to an array of device indices.
To allow constructing geometry instances with device code if desired, we need to be able to query a opaque handle for an acceleration structure. This handle is a value of 8 bytes. To get this handle, call:
// Provided by VK_NV_ray_tracing
VkResult vkGetAccelerationStructureHandleNV(
VkDevice device,
VkAccelerationStructureKHR accelerationStructure,
size_t dataSize,
void* pData);
-
device
is the logical device that owns the acceleration structures. -
accelerationStructure
is the acceleration structure. -
dataSize
is the size in bytes of the buffer pointed to bypData
. -
pData
is a pointer to a user-allocated buffer where the results will be written.
To query the 64-bit device address for an acceleration structure, call:
// Provided by VK_KHR_ray_tracing
VkDeviceAddress vkGetAccelerationStructureDeviceAddressKHR(
VkDevice device,
const VkAccelerationStructureDeviceAddressInfoKHR* pInfo);
-
device
is the logical device that the accelerationStructure was created on. -
pInfo
is a pointer to a VkAccelerationStructureDeviceAddressInfoKHR structure specifying the acceleration structure to retrieve an address for.
The 64-bit return value is an address of the acceleration structure, which can be used for device and shader operations that involve acceleration structures, such as ray traversal and acceleration structure building.
If the acceleration structure was created with a non-zero value of
VkAccelerationStructureCreateInfoKHR::deviceAddress
the return
value will be the same address.
The VkAccelerationStructureDeviceAddressInfoKHR
structure is defined
as:
// Provided by VK_KHR_ray_tracing
typedef struct VkAccelerationStructureDeviceAddressInfoKHR {
VkStructureType sType;
const void* pNext;
VkAccelerationStructureKHR accelerationStructure;
} VkAccelerationStructureDeviceAddressInfoKHR;
-
sType
is the type of this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
accelerationStructure
specifies the acceleration structure whose address is being queried.