Registered Extension Number

466

Revision

1

Ratification Status

Not ratified

Extension and Version Dependencies

API Interactions

  • Interacts with VK_VERSION_1_3

  • Interacts with VK_KHR_dynamic_rendering

Special Use

Contact

Extension Proposal

Other Extension Metadata

Last Modified Date

2022-03-31

Contributors
  • Shahbaz Youssefi, Google

  • Graeme Leese, Broadcom

  • Jan-Harald Fredriksen, Arm

Description

This extension exposes a hardware feature used by some vendors to implement OpenGL’s dithering. The purpose of this extension is to support layering OpenGL over Vulkan, by allowing the layer to take advantage of the same hardware feature and provide equivalent dithering to OpenGL applications.

New Structures

New Enum Constants

  • VK_EXT_LEGACY_DITHERING_EXTENSION_NAME

  • VK_EXT_LEGACY_DITHERING_SPEC_VERSION

  • Extending VkStructureType:

    • VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_LEGACY_DITHERING_FEATURES_EXT

  • Extending VkSubpassDescriptionFlagBits:

    • VK_SUBPASS_DESCRIPTION_ENABLE_LEGACY_DITHERING_BIT_EXT

If VK_KHR_dynamic_rendering is supported:

If Version 1.3 is supported:

Version History

  • Revision 1, 2022-03-31 (Shahbaz Youssefi)

    • Internal revisions

Issues

1) In OpenGL, the dither state can change dynamically. Should this extension add a pipeline state for dither?

RESOLVED: No. Changing dither state is rarely, if ever, done during rendering. Every surveyed Android application either entirely disables dither, explicitly enables it, or uses the default state (which is enabled). Additionally, on some hardware dither can only be specified in a render pass granularity, so a change in dither state would necessarily need to cause a render pass break. This extension considers dynamic changes in OpenGL dither state a theoretical situation, and expects the layer to break the render pass in such a situation without any practical downsides.

See Also

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.

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SPDX-License-Identifier: CC-BY-4.0