VkBindImageMemoryDeviceGroupInfo(3)

# VkBindImageMemoryDeviceGroupInfo(3) Manual Page

## Name

VkBindImageMemoryDeviceGroupInfo - Structure specifying device within a group to bind to

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## C Specification

    // 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;

## Members

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.

## Description

The `VkBindImageMemoryDeviceGroupInfo` structure is defined as:

- `sType` is the type of this structure.

- `pNext` is `NULL` or a pointer to a structure extending this structure.

- `deviceIndexCount` is the number of elements in `pDeviceIndices`.

- `pDeviceIndices` is a pointer to an array of device indices.

- `splitInstanceBindRegionCount` is the number of elements in `pSplitInstanceBindRegions`.

- `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.

Valid Usage

- At least one of `deviceIndexCount` and `splitInstanceBindRegionCount` must be zero

- `deviceIndexCount` must either be zero or equal to the number of physical devices in the logical device

- All elements of `pDeviceIndices` must be valid device indices

- `splitInstanceBindRegionCount` must either be zero or equal to the number of physical devices in the logical device squared

- Elements of `pSplitInstanceBindRegions` that correspond to the same instance of an image must not overlap

- The `offset.x` member of any element of `pSplitInstanceBindRegions` must be a multiple of the sparse image block width (`VkSparseImageFormatProperties`::`imageGranularity.width`) of all non-metadata aspects of the image

- The `offset.y` member of any element of `pSplitInstanceBindRegions` must be a multiple of the sparse image block height (`VkSparseImageFormatProperties`::`imageGranularity.height`) of all non-metadata aspects of the image

- The `extent.width` member of any element of `pSplitInstanceBindRegions` must either be a multiple of the sparse image block width of all non-metadata aspects of the image, or else `extent.width` + `offset.x` must equal the width of the image subresource

- The `extent.height` member of any element of `pSplitInstanceBindRegions` must either be a multiple of the sparse image block height of all non-metadata aspects of the image, or else `extent.height` + `offset.y` must equal the width of the image subresource

Valid Usage (Implicit)

- `sType` must be `VK_STRUCTURE_TYPE_BIND_IMAGE_MEMORY_DEVICE_GROUP_INFO`

- If `deviceIndexCount` is not `0`, `pDeviceIndices` must be a valid pointer to an array of `deviceIndexCount` `uint32_t` values

- If `splitInstanceBindRegionCount` is not `0`, `pSplitInstanceBindRegions` must be a valid pointer to an array of `splitInstanceBindRegionCount` VkRect2D structures

## See Also

VkRect2D, VkStructureType

## 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) 2014-2020 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0