C Specification
Information about the layout of the image subresource is returned in a
VkSubresourceLayout structure:
typedef struct VkSubresourceLayout {
VkDeviceSize offset;
VkDeviceSize size;
VkDeviceSize rowPitch;
VkDeviceSize arrayPitch;
VkDeviceSize depthPitch;
} VkSubresourceLayout;
Members
-
offsetis the byte offset from the start of the image or the plane where the image subresource begins. -
sizeis the size in bytes of the image subresource.sizeincludes any extra memory that is required based onrowPitch. -
rowPitchdescribes the number of bytes between each row of texels in an image. -
arrayPitchdescribes the number of bytes between each array layer of an image. -
depthPitchdescribes the number of bytes between each slice of 3D image.
Description
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
drmFormatModifierPlaneCount
associated with the image’s 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.
See Also
Document Notes
For more information, see the Vulkan Specification
This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.
Copyright
Copyright (c) 2014-2019 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.