# VkSubresourceLayout(3) Manual Page

## Name

VkSubresourceLayout - Structure specifying subresource layout

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## C Specification

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;

## Members

- `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 on `rowPitch`.

- `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.

## 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 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.

## See Also

VK_VERSION_1_0, VkDeviceSize, VkImageDrmFormatModifierExplicitCreateInfoEXT, VkSubresourceLayout2, vkGetImageSubresourceLayout

## 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 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0