VK_ARM_rasterization_order_attachment_access

Other Extension Metadata

Last Modified Date

2021-11-12

IP Status

No known IP claims.

Contributors

• Tobias Hector, AMD
• Jan-Harald Fredriksen, Arm

Description

Render passes, and specifically subpass dependencies, enable much of the same functionality as the framebuffer fetch and pixel local storage extensions did for OpenGL ES. But certain techniques such as programmable blending are awkward or impractical to implement with these alone, in part because a self-dependency is required every time a fragment will read a value at a given sample coordinate.

This extension extends the mechanism of input attachments to allow access to framebuffer attachments when used as both input and color, or depth/stencil, attachments from one fragment to the next, in rasterization order, without explicit synchronization.

New Structures

• Extending VkPhysicalDeviceFeatures2, VkDeviceCreateInfo:
  • VkPhysicalDeviceRasterizationOrderAttachmentAccessFeaturesARM

New Enum Constants

• VK_ARM_RASTERIZATION_ORDER_ATTACHMENT_ACCESS_EXTENSION_NAME
• VK_ARM_RASTERIZATION_ORDER_ATTACHMENT_ACCESS_SPEC_VERSION
• Extending VkPipelineColorBlendStateCreateFlagBits:
  • VK_PIPELINE_COLOR_BLEND_STATE_CREATE_RASTERIZATION_ORDER_ATTACHMENT_ACCESS_BIT_ARM
• Extending VkPipelineDepthStencilStateCreateFlagBits:
  • VK_PIPELINE_DEPTH_STENCIL_STATE_CREATE_RASTERIZATION_ORDER_ATTACHMENT_DEPTH_ACCESS_BIT_ARM
  • VK_PIPELINE_DEPTH_STENCIL_STATE_CREATE_RASTERIZATION_ORDER_ATTACHMENT_STENCIL_ACCESS_BIT_ARM
• Extending VkStructureType:
  • VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RASTERIZATION_ORDER_ATTACHMENT_ACCESS_FEATURES_ARM
• Extending VkSubpassDescriptionFlagBits:
  • VK_SUBPASS_DESCRIPTION_RASTERIZATION_ORDER_ATTACHMENT_COLOR_ACCESS_BIT_ARM
  • VK_SUBPASS_DESCRIPTION_RASTERIZATION_ORDER_ATTACHMENT_DEPTH_ACCESS_BIT_ARM
  • VK_SUBPASS_DESCRIPTION_RASTERIZATION_ORDER_ATTACHMENT_STENCIL_ACCESS_BIT_ARM

Issues

1) Is there any interaction with the VK_KHR_dynamic_rendering extension?

No. This extension only affects reads from input attachments. Render pass instances begun with vkCmdBeginRenderingKHR do not have input attachments and a different mechanism will be needed to provide similar functionality in this case.

Examples

None.

Version History

• Revision 1, 2021-11-12 (Jan-Harald Fredriksen)
  • Initial draft