33. Sparse Resources
As documented in Resource Memory Association,
VkBuffer
and VkImage
resources in Vulkan must be bound
completely and contiguously to a single VkDeviceMemory
object.
This binding must be done before the resource is used, and the binding is
immutable for the lifetime of the resource.
Sparse resources relax these restrictions and provide these additional features:
-
Sparse resources can be bound non-contiguously to one or more
VkDeviceMemory
allocations. -
Sparse resources can be re-bound to different memory allocations over the lifetime of the resource.
-
Sparse resources can have descriptors generated and used orthogonally with memory binding commands.
33.1. Sparse Resource Features
Sparse resources have several features that must be enabled explicitly at
resource creation time.
The features are enabled by including bits in the flags
parameter of
VkImageCreateInfo or VkBufferCreateInfo.
Each feature also has one or more corresponding feature enables specified in
VkPhysicalDeviceFeatures.
-
The
sparseBinding
feature is the base, and provides the following capabilities:-
Resources can be bound at some defined (sparse block) granularity.
-
The entire resource must be bound to memory before use regardless of regions actually accessed.
-
No specific mapping of image region to memory offset is defined, i.e. the location that each texel corresponds to in memory is implementation-dependent.
-
Sparse buffers have a well-defined mapping of buffer range to memory range, where an offset into a range of the buffer that is bound to a single contiguous range of memory corresponds to an identical offset within that range of memory.
-
Requested via the
VK_IMAGE_CREATE_SPARSE_BINDING_BIT
andVK_BUFFER_CREATE_SPARSE_BINDING_BIT
bits. -
A sparse image created using
VK_IMAGE_CREATE_SPARSE_BINDING_BIT
(but notVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
) supports all formats that non-sparse usage supports, and supports bothVK_IMAGE_TILING_OPTIMAL
andVK_IMAGE_TILING_LINEAR
tiling.
-
-
Sparse Residency builds on (and requires) the
sparseBinding
feature. It includes the following capabilities:-
Resources do not have to be completely bound to memory before use on the device.
-
Images have a prescribed sparse image block layout, allowing specific rectangular regions of the image to be bound to specific offsets in memory allocations.
-
Consistency of access to unbound regions of the resource is defined by the absence or presence of
VkPhysicalDeviceSparseProperties
::residencyNonResidentStrict
. If this property is present, accesses to unbound regions of the resource are well defined and behave as if the data bound is populated with all zeros; writes are discarded. When this property is absent, accesses are considered safe, but reads will return undefined values. -
Requested via the
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
andVK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT
bits. -
Sparse residency support is advertised on a finer grain via the following features:
-
The
sparseResidencyBuffer
feature provides support for creatingVkBuffer
objects with theVK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT
. -
The
sparseResidencyImage2D
feature provides support for creating 2D single-sampledVkImage
objects withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
The
sparseResidencyImage3D
feature provides support for creating 3DVkImage
objects withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
The
sparseResidency2Samples
feature provides support for creating 2DVkImage
objects with 2 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
The
sparseResidency4Samples
feature provides support for creating 2DVkImage
objects with 4 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
The
sparseResidency8Samples
feature provides support for creating 2DVkImage
objects with 8 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
The
sparseResidency16Samples
feature provides support for creating 2DVkImage
objects with 16 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
.
Implementations supporting
sparseResidencyImage2D
are only required to support sparse 2D, single-sampled images. Support for sparse 3D and MSAA images is optional and can be enabled viasparseResidencyImage3D
,sparseResidency2Samples
,sparseResidency4Samples
,sparseResidency8Samples
, andsparseResidency16Samples
. -
-
A sparse image created using
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
supports all non-compressed color formats with power-of-two element size that non-sparse usage supports. Additional formats may also be supported and can be queried via vkGetPhysicalDeviceSparseImageFormatProperties.VK_IMAGE_TILING_LINEAR
tiling is not supported.
-
-
The
sparseResidencyAliased
feature provides the following capability that can be enabled per resource:Allows physical memory ranges to be shared between multiple locations in the same sparse resource or between multiple sparse resources, with each binding of a memory location observing a consistent interpretation of the memory contents.
See Sparse Memory Aliasing for more information.
33.2. Sparse Buffers and Fully-Resident Images
Both VkBuffer
and VkImage
objects created with the
VK_IMAGE_CREATE_SPARSE_BINDING_BIT
or
VK_BUFFER_CREATE_SPARSE_BINDING_BIT
bits can be thought of as a
linear region of address space.
In the VkImage
case if VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
is
not used, this linear region is entirely opaque, meaning that there is no
application-visible mapping between texel location and memory offset.
Unless VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
or
VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT
are also used, the entire
resource must be bound to one or more VkDeviceMemory
objects before
use.
33.2.1. Sparse Buffer and Fully-Resident Image Block Size
The sparse block size in bytes for sparse buffers and fully-resident images
is reported as VkMemoryRequirements
::alignment
.
alignment
represents both the memory alignment requirement and the
binding granularity (in bytes) for sparse resources.
33.3. Sparse Partially-Resident Buffers
VkBuffer
objects created with the
VK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT
bit allow the buffer to be made
only partially resident.
Partially resident VkBuffer
objects are allocated and bound
identically to VkBuffer
objects using only the
VK_BUFFER_CREATE_SPARSE_BINDING_BIT
feature.
The only difference is the ability for some regions of the buffer to be
unbound during device use.
33.4. Sparse Partially-Resident Images
VkImage
objects created with the
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
bit allow specific rectangular
regions of the image called sparse image blocks to be bound to specific
ranges of memory.
This allows the application to manage residency at either image subresource
or sparse image block granularity.
Each image subresource (outside of the mip tail)
starts on a sparse block boundary and has dimensions that are integer
multiples of the corresponding dimensions of the sparse image block.
Note
Applications can use these types of images to control LOD based on total memory consumption. If memory pressure becomes an issue the application can unbind and disable specific mipmap levels of images without having to recreate resources or modify texel data of unaffected levels. The application can also use this functionality to access subregions of the image in a “megatexture” fashion. The application can create a large image and only populate the region of the image that is currently being used in the scene. |
33.4.1. Accessing Unbound Regions
The following member of VkPhysicalDeviceSparseProperties
affects how
data in unbound regions of sparse resources are handled by the
implementation:
-
residencyNonResidentStrict
If this property is not present, reads of unbound regions of the image will return undefined values. Both reads and writes are still considered safe and will not affect other resources or populated regions of the image.
If this property is present, all reads of unbound regions of the image will behave as if the region was bound to memory populated with all zeros; writes will be discarded.
Image operations performed on unbound memory may still alter some component values in the natural way for those accesses, e.g. substituting a value of one for alpha in formats that do not have an alpha component.
Example: Reading the alpha component of an unbacked VK_FORMAT_R8_UNORM
image will return a value of 1.0f.
See Physical Device Enumeration for instructions for retrieving physical device properties.
33.4.2. Mip Tail Regions
Sparse images created using VK_IMAGE_CREATE_SPARSE_BINDING_BIT
(without also using VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
) have no
specific mapping of image region or image subresource to memory offset
defined, so the entire image can be thought of as a linear opaque address
region.
However, images created with VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
do
have a prescribed sparse image block layout, and hence each image
subresource must start on a sparse block boundary.
Within each array layer, the set of mip levels that have a smaller size than
the sparse block size in bytes are grouped together into a mip tail
region.
If the VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT
flag is present in
the flags
member of VkSparseImageFormatProperties
, for the
image’s format
, then any mip level which has dimensions that are not
integer multiples of the corresponding dimensions of the sparse image block,
and all subsequent mip levels, are also included in the mip tail region.
The following member of VkPhysicalDeviceSparseProperties
may affect
how the implementation places mip levels in the mip tail region:
-
residencyAlignedMipSize
Each mip tail region is bound to memory as an opaque region (i.e. must be bound using a VkSparseImageOpaqueMemoryBindInfo structure) and may be of a size greater than or equal to the sparse block size in bytes. This size is guaranteed to be an integer multiple of the sparse block size in bytes.
An implementation may choose to allow each array-layer’s mip tail region to
be bound to memory independently or require that all array-layer’s mip tail
regions be treated as one.
This is dictated by VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
in
VkSparseImageMemoryRequirements
::flags
.
The following diagrams depict how
VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT
and
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
alter memory usage and
requirements.
In the absence of VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT
and
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
, each array layer contains a
mip tail region containing texel data for all mip levels smaller than the
sparse image block in any dimension.
Mip levels that are as large or larger than a sparse image block in all dimensions can be bound individually. Right-edges and bottom-edges of each level are allowed to have partially used sparse blocks. Any bound partially-used-sparse-blocks must still have their full sparse block size in bytes allocated in memory.
When VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
is present all array
layers will share a single mip tail region.
Note
The mip tail regions are presented here in 2D arrays simply for figure size reasons. Each mip tail is logically a single array of sparse blocks with an implementation-dependent mapping of texels or compressed texel blocks to sparse blocks. |
When VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT
is present the first
mip level that would contain partially used sparse blocks begins the mip
tail region.
This level and all subsequent levels are placed in the mip tail.
Only the first N mip levels whose dimensions are an exact multiple of
the sparse image block dimensions can be bound and unbound on a sparse
block basis.
Note
The mip tail region is presented here in a 2D array simply for figure size reasons. It is logically a single array of sparse blocks with an implementation-dependent mapping of texels or compressed texel blocks to sparse blocks. |
When both VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT
and
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
are present the constraints
from each of these flags are in effect.
33.4.3. Standard Sparse Image Block Shapes
Standard sparse image block shapes define a standard set of dimensions for sparse image blocks that depend on the format of the image. Layout of texels or compressed texel blocks within a sparse image block is implementation-dependent. All currently defined standard sparse image block shapes are 64 KB in size.
For block-compressed formats (e.g. VK_FORMAT_BC5_UNORM_BLOCK
), the
texel size is the size of the compressed texel block (e.g. 128-bit for
BC5
) thus the dimensions of the standard sparse image block shapes
apply in terms of compressed texel blocks.
Note
For block-compressed formats, the dimensions of a sparse image block in terms of texels can be calculated by multiplying the sparse image block dimensions by the compressed texel block dimensions. |
TEXEL SIZE (bits) | Block Shape (2D) | Block Shape (3D) |
---|---|---|
8-Bit |
256 × 256 × 1 |
64 × 32 × 32 |
16-Bit |
256 × 128 × 1 |
32 × 32 × 32 |
32-Bit |
128 × 128 × 1 |
32 × 32 × 16 |
64-Bit |
128 × 64 × 1 |
32 × 16 × 16 |
128-Bit |
64 × 64 × 1 |
16 × 16 × 16 |
TEXEL SIZE (bits) | Block Shape (2X) | Block Shape (4X) | Block Shape (8X) | Block Shape (16X) |
---|---|---|---|---|
8-Bit |
128 × 256 × 1 |
128 × 128 × 1 |
64 × 128 × 1 |
64 × 64 × 1 |
16-Bit |
128 × 128 × 1 |
128 × 64 × 1 |
64 × 64 × 1 |
64 × 32 × 1 |
32-Bit |
64 × 128 × 1 |
64 × 64 × 1 |
32 × 64 × 1 |
32 × 32 × 1 |
64-Bit |
64 × 64 × 1 |
64 × 32 × 1 |
32 × 32 × 1 |
32 × 16 × 1 |
128-Bit |
32 × 64 × 1 |
32 × 32 × 1 |
16 × 32 × 1 |
16 × 16 × 1 |
Implementations that support the standard sparse image block shape for all
formats listed in the Standard Sparse Image Block Shapes (Single Sample) and
Standard Sparse Image Block Shapes (MSAA) tables may advertise the following
VkPhysicalDeviceSparseProperties
:
-
residencyStandard2DBlockShape
-
residencyStandard2DMultisampleBlockShape
-
residencyStandard3DBlockShape
Reporting each of these features does not imply that all possible image types are supported as sparse. Instead, this indicates that no supported sparse image of the corresponding type will use custom sparse image block dimensions for any formats that have a corresponding standard sparse image block shape.
33.4.4. Custom Sparse Image Block Shapes
An implementation that does not support a standard image block shape for a
particular sparse partially-resident image may choose to support a custom
sparse image block shape for it instead.
The dimensions of such a custom sparse image block shape are reported in
VkSparseImageFormatProperties
::imageGranularity
.
As with standard sparse image block shapes, the size in bytes of the custom
sparse image block shape will be reported in
VkMemoryRequirements
::alignment
.
Custom sparse image block dimensions are reported through
vkGetPhysicalDeviceSparseImageFormatProperties
and
vkGetImageSparseMemoryRequirements
.
An implementation must not support both the standard sparse image block shape and a custom sparse image block shape for the same image. The standard sparse image block shape must be used if it is supported.
33.4.5. Multiple Aspects
Partially resident images are allowed to report separate sparse properties for different aspects of the image. One example is for depth/stencil images where the implementation separates the depth and stencil data into separate planes. Another reason for multiple aspects is to allow the application to manage memory allocation for implementation-private metadata associated with the image. See the figure below:
Note
The mip tail regions are presented here in 2D arrays simply for figure size reasons. Each mip tail is logically a single array of sparse blocks with an implementation-dependent mapping of texels or compressed texel blocks to sparse blocks. |
In the figure above the depth, stencil, and metadata aspects all have unique
sparse properties.
The per-texel stencil data is ¼ the size of the depth data,
hence the stencil sparse blocks include 4 × the number of
texels.
The sparse block size in bytes for all of the aspects is identical and
defined by VkMemoryRequirements
::alignment
.
33.5. Sparse Memory Aliasing
By default sparse resources have the same aliasing rules as non-sparse resources. See Memory Aliasing for more information.
VkDevice
objects that have the sparseResidencyAliased
feature enabled are able to use the
VK_BUFFER_CREATE_SPARSE_ALIASED_BIT
and
VK_IMAGE_CREATE_SPARSE_ALIASED_BIT
flags for resource creation.
These flags allow resources to access physical memory bound into multiple
locations within one or more sparse resources in a data consistent
fashion.
This means that reading physical memory from multiple aliased locations will
return the same value.
Care must be taken when performing a write operation to aliased physical memory. Memory dependencies must be used to separate writes to one alias from reads or writes to another alias. Writes to aliased memory that are not properly guarded against accesses to different aliases will have undefined results for all accesses to the aliased memory.
Applications that wish to make use of data consistent sparse memory aliasing must abide by the following guidelines:
-
All sparse resources that are bound to aliased physical memory must be created with the
VK_BUFFER_CREATE_SPARSE_ALIASED_BIT
/VK_IMAGE_CREATE_SPARSE_ALIASED_BIT
flag. -
All resources that access aliased physical memory must interpret the memory in the same way. This implies the following:
-
Buffers and images cannot alias the same physical memory in a data consistent fashion. The physical memory ranges must be used exclusively by buffers or used exclusively by images for data consistency to be guaranteed.
-
Memory in sparse image mip tail regions cannot access aliased memory in a data consistent fashion.
-
Sparse images that alias the same physical memory must have compatible formats and be using the same sparse image block shape in order to access aliased memory in a data consistent fashion.
-
Failure to follow any of the above guidelines will require the application to abide by the normal, non-sparse resource aliasing rules. In this case memory cannot be accessed in a data consistent fashion.
Note
Enabling sparse resource memory aliasing can be a way to lower physical memory use, but it may reduce performance on some implementations. An application developer can test on their target HW and balance the memory / performance trade-offs measured. |
33.7. Sparse Resource API
The APIs related to sparse resources are grouped into the following categories:
33.7.1. Physical Device Features
Some sparse-resource related features are reported and enabled in
VkPhysicalDeviceFeatures
.
These features must be supported and enabled on the VkDevice
object
before applications can use them.
See Physical Device Features for information on how to get and
set enabled device features, and for more detailed explanations of these
features.
Sparse Physical Device Features
-
sparseBinding
: Support for creating VkBuffer andVkImage
objects with theVK_BUFFER_CREATE_SPARSE_BINDING_BIT
andVK_IMAGE_CREATE_SPARSE_BINDING_BIT
flags, respectively. -
sparseResidencyBuffer
: Support for creating VkBuffer objects with theVK_BUFFER_CREATE_SPARSE_RESIDENCY_BIT
flag. -
sparseResidencyImage2D
: Support for creating 2D single-sampledVkImage
objects withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
sparseResidencyImage3D
: Support for creating 3D VkImage objects withVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
sparseResidency2Samples
: Support for creating 2D VkImage objects with 2 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
sparseResidency4Samples
: Support for creating 2D VkImage objects with 4 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
sparseResidency8Samples
: Support for creating 2D VkImage objects with 8 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
sparseResidency16Samples
: Support for creating 2D VkImage objects with 16 samples andVK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
. -
sparseResidencyAliased
: Support for creating VkBuffer andVkImage
objects with theVK_BUFFER_CREATE_SPARSE_ALIASED_BIT
andVK_IMAGE_CREATE_SPARSE_ALIASED_BIT
flags, respectively.
33.7.2. Physical Device Sparse Properties
Some features of the implementation are not possible to disable, and are
reported to allow applications to alter their sparse resource usage
accordingly.
These read-only capabilities are reported in the
VkPhysicalDeviceProperties::sparseProperties
member, which is a
VkPhysicalDeviceSparseProperties
structure.
The VkPhysicalDeviceSparseProperties
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkPhysicalDeviceSparseProperties {
VkBool32 residencyStandard2DBlockShape;
VkBool32 residencyStandard2DMultisampleBlockShape;
VkBool32 residencyStandard3DBlockShape;
VkBool32 residencyAlignedMipSize;
VkBool32 residencyNonResidentStrict;
} VkPhysicalDeviceSparseProperties;
-
residencyStandard2DBlockShape
isVK_TRUE
if the physical device will access all single-sample 2D sparse resources using the standard sparse image block shapes (based on image format), as described in the Standard Sparse Image Block Shapes (Single Sample) table. If this property is not supported the value returned in theimageGranularity
member of theVkSparseImageFormatProperties
structure for single-sample 2D images is not required to match the standard sparse image block dimensions listed in the table. -
residencyStandard2DMultisampleBlockShape
isVK_TRUE
if the physical device will access all multisample 2D sparse resources using the standard sparse image block shapes (based on image format), as described in the Standard Sparse Image Block Shapes (MSAA) table. If this property is not supported, the value returned in theimageGranularity
member of theVkSparseImageFormatProperties
structure for multisample 2D images is not required to match the standard sparse image block dimensions listed in the table. -
residencyStandard3DBlockShape
isVK_TRUE
if the physical device will access all 3D sparse resources using the standard sparse image block shapes (based on image format), as described in the Standard Sparse Image Block Shapes (Single Sample) table. If this property is not supported, the value returned in theimageGranularity
member of theVkSparseImageFormatProperties
structure for 3D images is not required to match the standard sparse image block dimensions listed in the table. -
residencyAlignedMipSize
isVK_TRUE
if images with mip level dimensions that are not integer multiples of the corresponding dimensions of the sparse image block may be placed in the mip tail. If this property is not reported, only mip levels with dimensions smaller than theimageGranularity
member of theVkSparseImageFormatProperties
structure will be placed in the mip tail. If this property is reported the implementation is allowed to returnVK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT
in theflags
member ofVkSparseImageFormatProperties
, indicating that mip level dimensions that are not integer multiples of the corresponding dimensions of the sparse image block will be placed in the mip tail. -
residencyNonResidentStrict
specifies whether the physical device can consistently access non-resident regions of a resource. If this property isVK_TRUE
, access to non-resident regions of resources will be guaranteed to return values as if the resource was populated with 0; writes to non-resident regions will be discarded.
33.7.3. Sparse Image Format Properties
Given that certain aspects of sparse image support, including the sparse image block dimensions, may be implementation-dependent, vkGetPhysicalDeviceSparseImageFormatProperties can be used to query for sparse image format properties prior to resource creation. This command is used to check whether a given set of sparse image parameters is supported and what the sparse image block shape will be.
Sparse Image Format Properties API
The VkSparseImageFormatProperties
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkSparseImageFormatProperties {
VkImageAspectFlags aspectMask;
VkExtent3D imageGranularity;
VkSparseImageFormatFlags flags;
} VkSparseImageFormatProperties;
-
aspectMask
is a bitmask VkImageAspectFlagBits specifying which aspects of the image the properties apply to. -
imageGranularity
is the width, height, and depth of the sparse image block in texels or compressed texel blocks. -
flags
is a bitmask of VkSparseImageFormatFlagBits specifying additional information about the sparse resource.
Bits which may be set in VkSparseImageFormatProperties::flags
,
specifying additional information about the sparse resource, are:
// Provided by VK_VERSION_1_0
typedef enum VkSparseImageFormatFlagBits {
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT = 0x00000001,
VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT = 0x00000002,
VK_SPARSE_IMAGE_FORMAT_NONSTANDARD_BLOCK_SIZE_BIT = 0x00000004,
} VkSparseImageFormatFlagBits;
-
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
specifies that the image uses a single mip tail region for all array layers. -
VK_SPARSE_IMAGE_FORMAT_ALIGNED_MIP_SIZE_BIT
specifies that the first mip level whose dimensions are not integer multiples of the corresponding dimensions of the sparse image block begins the mip tail region. -
VK_SPARSE_IMAGE_FORMAT_NONSTANDARD_BLOCK_SIZE_BIT
specifies that the image uses non-standard sparse image block dimensions, and theimageGranularity
values do not match the standard sparse image block dimensions for the given format.
// Provided by VK_VERSION_1_0
typedef VkFlags VkSparseImageFormatFlags;
VkSparseImageFormatFlags
is a bitmask type for setting a mask of zero
or more VkSparseImageFormatFlagBits.
vkGetPhysicalDeviceSparseImageFormatProperties
returns an array of
VkSparseImageFormatProperties.
Each element will describe properties for one set of image aspects that are
bound simultaneously in the image.
This is usually one element for each aspect in the image, but for
interleaved depth/stencil images there is only one element describing the
combined aspects.
// Provided by VK_VERSION_1_0
void vkGetPhysicalDeviceSparseImageFormatProperties(
VkPhysicalDevice physicalDevice,
VkFormat format,
VkImageType type,
VkSampleCountFlagBits samples,
VkImageUsageFlags usage,
VkImageTiling tiling,
uint32_t* pPropertyCount,
VkSparseImageFormatProperties* pProperties);
-
physicalDevice
is the physical device from which to query the sparse image format properties. -
format
is the image format. -
type
is the dimensionality of image. -
samples
is a VkSampleCountFlagBits value specifying the number of samples per texel. -
usage
is a bitmask describing the intended usage of the image. -
tiling
is the tiling arrangement of the texel blocks in memory. -
pPropertyCount
is a pointer to an integer related to the number of sparse format properties available or queried, as described below. -
pProperties
is eitherNULL
or a pointer to an array of VkSparseImageFormatProperties structures.
If pProperties
is NULL
, then the number of sparse format properties
available is returned in pPropertyCount
.
Otherwise, pPropertyCount
must point to a variable set by the user to
the number of elements in the pProperties
array, and on return the
variable is overwritten with the number of structures actually written to
pProperties
.
If pPropertyCount
is less than the number of sparse format properties
available, at most pPropertyCount
structures will be written.
If VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
is not supported for the given
arguments, pPropertyCount
will be set to zero upon return, and no data
will be written to pProperties
.
Multiple aspects are returned for depth/stencil images that are implemented
as separate planes by the implementation.
The depth and stencil data planes each have unique
VkSparseImageFormatProperties
data.
Depth/stencil images with depth and stencil data interleaved into a single
plane will return a single VkSparseImageFormatProperties
structure
with the aspectMask
set to VK_IMAGE_ASPECT_DEPTH_BIT
|
VK_IMAGE_ASPECT_STENCIL_BIT
.
vkGetPhysicalDeviceSparseImageFormatProperties2
returns an array of
VkSparseImageFormatProperties2.
Each element will describe properties for one set of image aspects that are
bound simultaneously in the image.
This is usually one element for each aspect in the image, but for
interleaved depth/stencil images there is only one element describing the
combined aspects.
// Provided by VK_VERSION_1_1
void vkGetPhysicalDeviceSparseImageFormatProperties2(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceSparseImageFormatInfo2* pFormatInfo,
uint32_t* pPropertyCount,
VkSparseImageFormatProperties2* pProperties);
or the equivalent command
// Provided by VK_KHR_get_physical_device_properties2
void vkGetPhysicalDeviceSparseImageFormatProperties2KHR(
VkPhysicalDevice physicalDevice,
const VkPhysicalDeviceSparseImageFormatInfo2* pFormatInfo,
uint32_t* pPropertyCount,
VkSparseImageFormatProperties2* pProperties);
-
physicalDevice
is the physical device from which to query the sparse image format properties. -
pFormatInfo
is a pointer to a VkPhysicalDeviceSparseImageFormatInfo2 structure containing input parameters to the command. -
pPropertyCount
is a pointer to an integer related to the number of sparse format properties available or queried, as described below. -
pProperties
is eitherNULL
or a pointer to an array of VkSparseImageFormatProperties2 structures.
vkGetPhysicalDeviceSparseImageFormatProperties2
behaves identically to
vkGetPhysicalDeviceSparseImageFormatProperties, with the ability to
return extended information by adding extending structures to the
pNext
chain of its pProperties
parameter.
The VkPhysicalDeviceSparseImageFormatInfo2
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkPhysicalDeviceSparseImageFormatInfo2 {
VkStructureType sType;
const void* pNext;
VkFormat format;
VkImageType type;
VkSampleCountFlagBits samples;
VkImageUsageFlags usage;
VkImageTiling tiling;
} VkPhysicalDeviceSparseImageFormatInfo2;
or the equivalent
// Provided by VK_KHR_get_physical_device_properties2
typedef VkPhysicalDeviceSparseImageFormatInfo2 VkPhysicalDeviceSparseImageFormatInfo2KHR;
-
sType
is a VkStructureType value identifying this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
format
is the image format. -
type
is the dimensionality of image. -
samples
is a VkSampleCountFlagBits value specifying the number of samples per texel. -
usage
is a bitmask describing the intended usage of the image. -
tiling
is the tiling arrangement of the texel blocks in memory.
The VkSparseImageFormatProperties2
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkSparseImageFormatProperties2 {
VkStructureType sType;
void* pNext;
VkSparseImageFormatProperties properties;
} VkSparseImageFormatProperties2;
or the equivalent
// Provided by VK_KHR_get_physical_device_properties2
typedef VkSparseImageFormatProperties2 VkSparseImageFormatProperties2KHR;
-
sType
is a VkStructureType value identifying this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
properties
is a VkSparseImageFormatProperties structure which is populated with the same values as in vkGetPhysicalDeviceSparseImageFormatProperties.
33.7.4. Sparse Resource Creation
Sparse resources require that one or more sparse feature flags be specified
(as part of the VkPhysicalDeviceFeatures
structure described
previously in the Physical Device Features
section) when calling vkCreateDevice.
When the appropriate device features are enabled, the
VK_BUFFER_CREATE_SPARSE_*
and VK_IMAGE_CREATE_SPARSE_*
flags
can be used.
See vkCreateBuffer and vkCreateImage for details of the resource
creation APIs.
Note
Specifying |
33.7.5. Sparse Resource Memory Requirements
Sparse resources have specific memory requirements related to binding sparse
memory.
These memory requirements are reported differently for VkBuffer
objects and VkImage
objects.
Buffer and Fully-Resident Images
Buffers (both fully and partially resident) and fully-resident images can
be bound to memory using only the data from VkMemoryRequirements
.
For all sparse resources the VkMemoryRequirements
::alignment
member specifies both the bindable sparse block size in bytes and required
alignment of VkDeviceMemory
.
Partially Resident Images
Partially resident images have a different method for binding memory.
As with buffers and fully resident images, the
VkMemoryRequirements
::alignment
field specifies the bindable
sparse block size in bytes for the image.
Requesting sparse memory requirements for VkImage
objects using
vkGetImageSparseMemoryRequirements
will return an array of one or more
VkSparseImageMemoryRequirements
structures.
Each structure describes the sparse memory requirements for a group of
aspects of the image.
The sparse image must have been created using the
VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
flag to retrieve valid sparse
image memory requirements.
Sparse Image Memory Requirements
The VkSparseImageMemoryRequirements
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkSparseImageMemoryRequirements {
VkSparseImageFormatProperties formatProperties;
uint32_t imageMipTailFirstLod;
VkDeviceSize imageMipTailSize;
VkDeviceSize imageMipTailOffset;
VkDeviceSize imageMipTailStride;
} VkSparseImageMemoryRequirements;
-
formatProperties
is a VkSparseImageFormatProperties structure specifying properties of the image format. -
imageMipTailFirstLod
is the first mip level at which image subresources are included in the mip tail region. -
imageMipTailSize
is the memory size (in bytes) of the mip tail region. IfformatProperties.flags
containsVK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
, this is the size of the whole mip tail, otherwise this is the size of the mip tail of a single array layer. This value is guaranteed to be a multiple of the sparse block size in bytes. -
imageMipTailOffset
is the opaque memory offset used with VkSparseImageOpaqueMemoryBindInfo to bind the mip tail region(s). -
imageMipTailStride
is the offset stride between each array-layer’s mip tail, ifformatProperties.flags
does not containVK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
(otherwise the value is undefined).
To query sparse memory requirements for an image, call:
// Provided by VK_VERSION_1_0
void vkGetImageSparseMemoryRequirements(
VkDevice device,
VkImage image,
uint32_t* pSparseMemoryRequirementCount,
VkSparseImageMemoryRequirements* pSparseMemoryRequirements);
-
device
is the logical device that owns the image. -
image
is the VkImage object to get the memory requirements for. -
pSparseMemoryRequirementCount
is a pointer to an integer related to the number of sparse memory requirements available or queried, as described below. -
pSparseMemoryRequirements
is eitherNULL
or a pointer to an array ofVkSparseImageMemoryRequirements
structures.
If pSparseMemoryRequirements
is NULL
, then the number of sparse
memory requirements available is returned in
pSparseMemoryRequirementCount
.
Otherwise, pSparseMemoryRequirementCount
must point to a variable set
by the user to the number of elements in the pSparseMemoryRequirements
array, and on return the variable is overwritten with the number of
structures actually written to pSparseMemoryRequirements
.
If pSparseMemoryRequirementCount
is less than the number of sparse
memory requirements available, at most pSparseMemoryRequirementCount
structures will be written.
If the image was not created with VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
then pSparseMemoryRequirementCount
will be set to zero and
pSparseMemoryRequirements
will not be written to.
Note
It is legal for an implementation to report a larger value in
|
To query sparse memory requirements for an image, call:
// Provided by VK_VERSION_1_1
void vkGetImageSparseMemoryRequirements2(
VkDevice device,
const VkImageSparseMemoryRequirementsInfo2* pInfo,
uint32_t* pSparseMemoryRequirementCount,
VkSparseImageMemoryRequirements2* pSparseMemoryRequirements);
or the equivalent command
// Provided by VK_KHR_get_memory_requirements2
void vkGetImageSparseMemoryRequirements2KHR(
VkDevice device,
const VkImageSparseMemoryRequirementsInfo2* pInfo,
uint32_t* pSparseMemoryRequirementCount,
VkSparseImageMemoryRequirements2* pSparseMemoryRequirements);
-
device
is the logical device that owns the image. -
pInfo
is a pointer to aVkImageSparseMemoryRequirementsInfo2
structure containing parameters required for the memory requirements query. -
pSparseMemoryRequirementCount
is a pointer to an integer related to the number of sparse memory requirements available or queried, as described below. -
pSparseMemoryRequirements
is eitherNULL
or a pointer to an array ofVkSparseImageMemoryRequirements2
structures.
To determine the sparse memory requirements for an image resource without creating an object, call:
// Provided by VK_VERSION_1_3
void vkGetDeviceImageSparseMemoryRequirements(
VkDevice device,
const VkDeviceImageMemoryRequirements* pInfo,
uint32_t* pSparseMemoryRequirementCount,
VkSparseImageMemoryRequirements2* pSparseMemoryRequirements);
or the equivalent command
// Provided by VK_KHR_maintenance4
void vkGetDeviceImageSparseMemoryRequirementsKHR(
VkDevice device,
const VkDeviceImageMemoryRequirements* pInfo,
uint32_t* pSparseMemoryRequirementCount,
VkSparseImageMemoryRequirements2* pSparseMemoryRequirements);
-
device
is the logical device intended to own the image. -
pInfo
is a pointer to a VkDeviceImageMemoryRequirements structure containing parameters required for the memory requirements query. -
pSparseMemoryRequirementCount
is a pointer to an integer related to the number of sparse memory requirements available or queried, as described below. -
pSparseMemoryRequirements
is eitherNULL
or a pointer to an array ofVkSparseImageMemoryRequirements2
structures.
The VkImageSparseMemoryRequirementsInfo2
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkImageSparseMemoryRequirementsInfo2 {
VkStructureType sType;
const void* pNext;
VkImage image;
} VkImageSparseMemoryRequirementsInfo2;
or the equivalent
// Provided by VK_KHR_get_memory_requirements2
typedef VkImageSparseMemoryRequirementsInfo2 VkImageSparseMemoryRequirementsInfo2KHR;
-
sType
is a VkStructureType value identifying this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
image
is the image to query.
The VkSparseImageMemoryRequirements2
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkSparseImageMemoryRequirements2 {
VkStructureType sType;
void* pNext;
VkSparseImageMemoryRequirements memoryRequirements;
} VkSparseImageMemoryRequirements2;
or the equivalent
// Provided by VK_KHR_get_memory_requirements2
typedef VkSparseImageMemoryRequirements2 VkSparseImageMemoryRequirements2KHR;
-
sType
is a VkStructureType value identifying this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
memoryRequirements
is a VkSparseImageMemoryRequirements structure describing the memory requirements of the sparse image.
33.7.6. Binding Resource Memory
Non-sparse resources are backed by a single physical allocation prior to
device use (via vkBindImageMemory
or vkBindBufferMemory
), and
their backing must not be changed.
On the other hand, sparse resources can be bound to memory non-contiguously
and these bindings can be altered during the lifetime of the resource.
Note
It is important to note that freeing a |
Sparse memory bindings execute on a queue that includes the
VK_QUEUE_SPARSE_BINDING_BIT
bit.
Applications must use synchronization primitives to
guarantee that other queues do not access ranges of memory concurrently with
a binding change.
Applications can access other ranges of the same resource while a bind
operation is executing.
Note
Implementations must provide a guarantee that simultaneously binding sparse blocks while another queue accesses those same sparse blocks via a sparse resource must not access memory owned by another process or otherwise corrupt the system. |
While some implementations may include VK_QUEUE_SPARSE_BINDING_BIT
support in queue families that also include graphics and compute support,
other implementations may only expose a
VK_QUEUE_SPARSE_BINDING_BIT
-only queue family.
In either case, applications must use synchronization
primitives to explicitly request any ordering dependencies between sparse
memory binding operations and other graphics/compute/transfer operations, as
sparse binding operations are not automatically ordered against command
buffer execution, even within a single queue.
When binding memory explicitly for the VK_IMAGE_ASPECT_METADATA_BIT
the application must use the VK_SPARSE_MEMORY_BIND_METADATA_BIT
in
the VkSparseMemoryBind
::flags
field when binding memory.
Binding memory for metadata is done the same way as binding memory for the
mip tail, with the addition of the VK_SPARSE_MEMORY_BIND_METADATA_BIT
flag.
Binding the mip tail for any aspect must only be performed using
VkSparseImageOpaqueMemoryBindInfo.
If formatProperties.flags
contains
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
, then it can be bound with
a single VkSparseMemoryBind structure, with resourceOffset
=
imageMipTailOffset
and size
= imageMipTailSize
.
If formatProperties.flags
does not contain
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
then the offset for the mip
tail in each array layer is given as:
arrayMipTailOffset = imageMipTailOffset + arrayLayer * imageMipTailStride;
and the mip tail can be bound with layerCount
VkSparseMemoryBind
structures, each using size
= imageMipTailSize
and
resourceOffset
= arrayMipTailOffset
as defined above.
Sparse memory binding is handled by the following APIs and related data structures.
Sparse Memory Binding Functions
The VkSparseMemoryBind
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkSparseMemoryBind {
VkDeviceSize resourceOffset;
VkDeviceSize size;
VkDeviceMemory memory;
VkDeviceSize memoryOffset;
VkSparseMemoryBindFlags flags;
} VkSparseMemoryBind;
-
resourceOffset
is the offset into the resource. -
size
is the size of the memory region to be bound. -
memory
is the VkDeviceMemory object that the range of the resource is bound to. Ifmemory
is VK_NULL_HANDLE, the range is unbound. -
memoryOffset
is the offset into the VkDeviceMemory object to bind the resource range to. Ifmemory
is VK_NULL_HANDLE, this value is ignored. -
flags
is a bitmask of VkSparseMemoryBindFlagBits specifying usage of the binding operation.
The binding range [resourceOffset
, resourceOffset
+
size
) has different constraints based on flags
.
If flags
contains VK_SPARSE_MEMORY_BIND_METADATA_BIT
, the
binding range must be within the mip tail region of the metadata aspect.
This metadata region is defined by:
-
metadataRegion = [base, base +
imageMipTailSize
) -
base =
imageMipTailOffset
+imageMipTailStride
× n
and imageMipTailOffset
, imageMipTailSize
, and
imageMipTailStride
values are from the
VkSparseImageMemoryRequirements corresponding to the metadata aspect
of the image, and n is a valid array layer index for the image,
imageMipTailStride
is considered to be zero for aspects where
VkSparseImageMemoryRequirements
::formatProperties.flags
contains
VK_SPARSE_IMAGE_FORMAT_SINGLE_MIPTAIL_BIT
.
If flags
does not contain VK_SPARSE_MEMORY_BIND_METADATA_BIT
,
the binding range must be within the range
[0,VkMemoryRequirements::size
).
Bits which can be set in VkSparseMemoryBind::flags
, specifying
usage of a sparse memory binding operation, are:
// Provided by VK_VERSION_1_0
typedef enum VkSparseMemoryBindFlagBits {
VK_SPARSE_MEMORY_BIND_METADATA_BIT = 0x00000001,
} VkSparseMemoryBindFlagBits;
-
VK_SPARSE_MEMORY_BIND_METADATA_BIT
specifies that the memory being bound is only for the metadata aspect.
// Provided by VK_VERSION_1_0
typedef VkFlags VkSparseMemoryBindFlags;
VkSparseMemoryBindFlags
is a bitmask type for setting a mask of zero
or more VkSparseMemoryBindFlagBits.
Memory is bound to VkBuffer
objects created with the
VK_BUFFER_CREATE_SPARSE_BINDING_BIT
flag using the following
structure:
// Provided by VK_VERSION_1_0
typedef struct VkSparseBufferMemoryBindInfo {
VkBuffer buffer;
uint32_t bindCount;
const VkSparseMemoryBind* pBinds;
} VkSparseBufferMemoryBindInfo;
-
buffer
is the VkBuffer object to be bound. -
bindCount
is the number of VkSparseMemoryBind structures in thepBinds
array. -
pBinds
is a pointer to an array of VkSparseMemoryBind structures.
Memory is bound to opaque regions of VkImage
objects created with the
VK_IMAGE_CREATE_SPARSE_BINDING_BIT
flag using the following structure:
// Provided by VK_VERSION_1_0
typedef struct VkSparseImageOpaqueMemoryBindInfo {
VkImage image;
uint32_t bindCount;
const VkSparseMemoryBind* pBinds;
} VkSparseImageOpaqueMemoryBindInfo;
-
image
is the VkImage object to be bound. -
bindCount
is the number of VkSparseMemoryBind structures in thepBinds
array. -
pBinds
is a pointer to an array of VkSparseMemoryBind structures.
Note
This operation is normally used to bind memory to fully-resident sparse images or for mip tail regions of partially resident images. However, it can also be used to bind memory for the entire binding range of partially resident images. In case When |
editing-note
(Jon) The preceding NOTE refers to |
Memory can be bound to sparse image blocks of VkImage
objects created
with the VK_IMAGE_CREATE_SPARSE_RESIDENCY_BIT
flag using the following
structure:
// Provided by VK_VERSION_1_0
typedef struct VkSparseImageMemoryBindInfo {
VkImage image;
uint32_t bindCount;
const VkSparseImageMemoryBind* pBinds;
} VkSparseImageMemoryBindInfo;
-
image
is the VkImage object to be bound -
bindCount
is the number of VkSparseImageMemoryBind structures inpBinds
array -
pBinds
is a pointer to an array of VkSparseImageMemoryBind structures
The VkSparseImageMemoryBind
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkSparseImageMemoryBind {
VkImageSubresource subresource;
VkOffset3D offset;
VkExtent3D extent;
VkDeviceMemory memory;
VkDeviceSize memoryOffset;
VkSparseMemoryBindFlags flags;
} VkSparseImageMemoryBind;
-
subresource
is the image aspect and region of interest in the image. -
offset
are the coordinates of the first texel within the image subresource to bind. -
extent
is the size in texels of the region within the image subresource to bind. The extent must be a multiple of the sparse image block dimensions, except when binding sparse image blocks along the edge of an image subresource it can instead be such that any coordinate ofoffset
+extent
equals the corresponding dimensions of the image subresource. -
memory
is the VkDeviceMemory object that the sparse image blocks of the image are bound to. Ifmemory
is VK_NULL_HANDLE, the sparse image blocks are unbound. -
memoryOffset
is an offset into VkDeviceMemory object. Ifmemory
is VK_NULL_HANDLE, this value is ignored. -
flags
are sparse memory binding flags.
To submit sparse binding operations to a queue, call:
// Provided by VK_VERSION_1_0
VkResult vkQueueBindSparse(
VkQueue queue,
uint32_t bindInfoCount,
const VkBindSparseInfo* pBindInfo,
VkFence fence);
-
queue
is the queue that the sparse binding operations will be submitted to. -
bindInfoCount
is the number of elements in thepBindInfo
array. -
pBindInfo
is a pointer to an array of VkBindSparseInfo structures, each specifying a sparse binding submission batch. -
fence
is an optional handle to a fence to be signaled. Iffence
is not VK_NULL_HANDLE, it defines a fence signal operation.
vkQueueBindSparse
is a queue submission
command, with each batch defined by an element of pBindInfo
as a
VkBindSparseInfo structure.
Batches begin execution in the order they appear in pBindInfo
, but
may complete out of order.
Within a batch, a given range of a resource must not be bound more than once. Across batches, if a range is to be bound to one allocation and offset and then to another allocation and offset, then the application must guarantee (usually using semaphores) that the binding operations are executed in the correct order, as well as to order binding operations against the execution of command buffer submissions.
As no operation to vkQueueBindSparse causes any pipeline stage to access memory, synchronization primitives used in this command effectively only define execution dependencies.
Additional information about fence and semaphore operation is described in the synchronization chapter.
The VkBindSparseInfo
structure is defined as:
// Provided by VK_VERSION_1_0
typedef struct VkBindSparseInfo {
VkStructureType sType;
const void* pNext;
uint32_t waitSemaphoreCount;
const VkSemaphore* pWaitSemaphores;
uint32_t bufferBindCount;
const VkSparseBufferMemoryBindInfo* pBufferBinds;
uint32_t imageOpaqueBindCount;
const VkSparseImageOpaqueMemoryBindInfo* pImageOpaqueBinds;
uint32_t imageBindCount;
const VkSparseImageMemoryBindInfo* pImageBinds;
uint32_t signalSemaphoreCount;
const VkSemaphore* pSignalSemaphores;
} VkBindSparseInfo;
-
sType
is a VkStructureType value identifying this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
waitSemaphoreCount
is the number of semaphores upon which to wait before executing the sparse binding operations for the batch. -
pWaitSemaphores
is a pointer to an array of semaphores upon which to wait on before the sparse binding operations for this batch begin execution. If semaphores to wait on are provided, they define a semaphore wait operation. -
bufferBindCount
is the number of sparse buffer bindings to perform in the batch. -
pBufferBinds
is a pointer to an array of VkSparseBufferMemoryBindInfo structures. -
imageOpaqueBindCount
is the number of opaque sparse image bindings to perform. -
pImageOpaqueBinds
is a pointer to an array of VkSparseImageOpaqueMemoryBindInfo structures, indicating opaque sparse image bindings to perform. -
imageBindCount
is the number of sparse image bindings to perform. -
pImageBinds
is a pointer to an array of VkSparseImageMemoryBindInfo structures, indicating sparse image bindings to perform. -
signalSemaphoreCount
is the number of semaphores to be signaled once the sparse binding operations specified by the structure have completed execution. -
pSignalSemaphores
is a pointer to an array of semaphores which will be signaled when the sparse binding operations for this batch have completed execution. If semaphores to be signaled are provided, they define a semaphore signal operation.
To specify the values to use when waiting for and signaling semaphores
created with a VkSemaphoreType of VK_SEMAPHORE_TYPE_TIMELINE
,
add a VkTimelineSemaphoreSubmitInfo structure to the pNext
chain
of the VkBindSparseInfo structure.
If the pNext
chain of VkBindSparseInfo includes a
VkDeviceGroupBindSparseInfo
structure, then that structure includes
device indices specifying which instance of the resources and memory are
bound.
The VkDeviceGroupBindSparseInfo
structure is defined as:
// Provided by VK_VERSION_1_1
typedef struct VkDeviceGroupBindSparseInfo {
VkStructureType sType;
const void* pNext;
uint32_t resourceDeviceIndex;
uint32_t memoryDeviceIndex;
} VkDeviceGroupBindSparseInfo;
or the equivalent
// Provided by VK_KHR_device_group
typedef VkDeviceGroupBindSparseInfo VkDeviceGroupBindSparseInfoKHR;
-
sType
is a VkStructureType value identifying this structure. -
pNext
isNULL
or a pointer to a structure extending this structure. -
resourceDeviceIndex
is a device index indicating which instance of the resource is bound. -
memoryDeviceIndex
is a device index indicating which instance of the memory the resource instance is bound to.
These device indices apply to all buffer and image memory binds included in
the batch pointing to this structure.
The semaphore waits and signals for the batch are executed only by the
physical device specified by the resourceDeviceIndex
.
If this structure is not present, resourceDeviceIndex
and
memoryDeviceIndex
are assumed to be zero.