VK_QCOM_multiview_per_view_render_areas(3)

# VK_QCOM_multiview_per_view_render_areas(3) Manual Page

## Name

VK_QCOM_multiview_per_view_render_areas - device extension

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## Registered Extension Number

511

## Revision

1

## Ratification Status

Not ratified

## Extension and Version Dependencies

## Contact

- Jeff Leger jackohound

## Other Extension Metadata

Last Modified Date

  2023-01-10

IP Status

  No known IP claims.

Interactions and External Dependencies

  - This extension interacts with `VK_KHR_dynamic_rendering`

  - This extension interacts with `VK_QCOM_render_pass_transform`

Contributors

  - Jeff Leger, Qualcomm

  - Jonathan Tinkham, Qualcomm

  - Jonathan Wicks, Qualcomm

## Description

Certain use-cases (e.g., side-by-side VR rendering) use multiview and render to distinct regions of the framebuffer for each view. On some implementations, there may be a performance benefit for providing per-view render areas to the implementation. Such per-view render areas can be used by the implementation to reduce the pixels that are affected by attachment load, store, and multisample resolve operations.

The extension enables a multiview render pass instance to define per-view render areas. For each view of a multiview render pass instance, only those pixels in the per-view render area are affected by load, store and resolve operations.

## New Structures

- Extending VkPhysicalDeviceFeatures2, VkDeviceCreateInfo:

  - VkPhysicalDeviceMultiviewPerViewRenderAreasFeaturesQCOM

- Extending VkRenderPassBeginInfo, VkRenderingInfo:

  - VkMultiviewPerViewRenderAreasRenderPassBeginInfoQCOM

## New Enum Constants

- `VK_QCOM_MULTIVIEW_PER_VIEW_RENDER_AREAS_EXTENSION_NAME`

- `VK_QCOM_MULTIVIEW_PER_VIEW_RENDER_AREAS_SPEC_VERSION`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_MULTIVIEW_PER_VIEW_RENDER_AREAS_RENDER_PASS_BEGIN_INFO_QCOM`

  - `VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_MULTIVIEW_PER_VIEW_RENDER_AREAS_FEATURES_QCOM`

## Issues

1) Do the per-view `renderAreas` interact with vkGetRenderAreaGranularity ?

RESOLVED: There is no change. The granularity returned by vkGetRenderAreaGranularity also applies to the per-view `renderAreas`.

2) How does this extension interact with `VK_QCOM_render_pass_transform`?

RESOLVED: When `VK_QCOM_render_pass_transform` is enabled, the application provides render area in non-rotated coordinates which is rotated by the implementation to the rotated coordinate system. When this extension is used in combination with `VK_QCOM_render_pass_transform`, then the `renderArea` provided in VkRenderingInfo::`renderArea`, VkRenderPassBeginInfo::`renderArea`, or VkCommandBufferInheritanceRenderPassTransformInfoQCOM::`renderArea` is rotated by the implementation. The per-view render areas are not rotated.

3) How does this extension interact with `VK_QCOM_multiview_per_view_viewports`

RESOLVED: There is no direct interaction. The per-view viewports and the per-view renderAreas are orthogonal features.

4) When a per-view `renderArea` is specified, must multiview rendering for each view of a multiview render pass be contained within the per-view `renderArea`?

RESOLVED: Yes, and the `VK_QCOM_multiview_per_view_viewports` may help here since it provides per-view scissors.

5) When per-view render areas are specified, what purpose if any do VkRenderPassBeginInfo::`renderArea` and VkRenderingInfo::`renderArea` serve?

RESOLVED: The per-view `renderArea` effectively overrides the per-renderpass `renderArea`. The per-view `renderArea` defines the regions of the attachments that are effected by load, store, and multisample resolve operations. A valid implementation could ignore the per-renderpass `renderArea`. However, as an aid to the implementation, the application must set the per-renderpass `renderArea` to an area that is at least as large as the union of all the per-view render areas. Pixels that are within the per-renderpass `renderArea` but not within any per-view render area must not be affected by load, store, or multisample resolve operations.

## Version History

- Revision 1, 2023-01-10 (Jeff Leger)

## See Also

VkMultiviewPerViewRenderAreasRenderPassBeginInfoQCOM, VkPhysicalDeviceMultiviewPerViewRenderAreasFeaturesQCOM

## Document Notes

For more information, see the Vulkan Specification

This page is a generated document. Fixes and changes should be made to the generator scripts, not directly.

## Copyright

Copyright 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0