Commit dff47d5fdaac04d1eb9343308c903157203467ce
2020-07-14T19:10:12
Vulkan: Optimize MSAA using subpass resolve attachments If a user is performing a blit to resolve a multisample color buffer into a single attachment, ANGLE can use subpass resolve attachments to resolve directly into the destination buffer as part of the render pass. This allows the data to remain in tiler memory and reduce the extra bandwidth required to write the multisampled data back to perform the copy. This work also requires restoring/reopening a render pass if it has been finished already, assuming the finished render pass was started and for the framebuffer that is the source for the blit command. Other objects that were created when the render pass was started need to be updated as well, such as the source FramebufferVk's resolve attachment, the CommandBufferHelper's vk::Framebuffer and vk::RenderPassDesc, etc. While this is better than performing vkCmdResolveImage(), there is still another major part of optimizing MSAA using resolve attachments not implemented here: discarding the multisampled image rather than writing it to GMEM, which requires the user to invalidate the read FBO after the blit. This CL was verified with AGI to make sure there are no explicit blits to resolve the multiple sampled image. Bug: b/159903491 Test: FramebufferTest_ES31.*Blit* Test: VulkanPerformanceCounterTest_ES31.MultisampleResolveWithBlit Change-Id: I320a26088d8f614a295e7feec275d71310391806 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2298663 Commit-Queue: Tim Van Patten <timvp@google.com> Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com>