kc3-lang/angle

2024-10-10T16:53:15

Vulkan: Isolate framebuffer fetch no-RP-break optim from DR Prior to [1], changes to framebuffer fetch usage by shaders caused a render pass break. This was due to a limitation of render pass compatibility rules. It also caused other headache, such as needing to clear the render pass cache, recreating pipelines etc. [1]:https://chromium-review.googlesource.com/c/angle/angle/+/3697308 In [1] an important optimization was implemented for tiling GPUs where ANGLE permanently switched to framebuffer fetch mode on first encountering framebuffer fetch use. From that point on, ANGLE would always make every render pass framebuffer fetch compatible. In reality, the render pass break was unnecessary, which became apparent with dynamic rendering (for example that whether the render pass includes input attachments has no bearing on a pipeline that doesn't use input attachments at all). In [2], dynamic rendering kept the render pass break + permanent switch behavior for simplicity. [2]:https://chromium-review.googlesource.com/c/angle/angle/+/5637155 This change untangles the optimization done for legacy render passes from dynamic rendering, allowing dynamic rendering to start every render pass without framebuffer fetch and enable it later if a framebuffer fetch program is used. This is in preparation for supporting depth/stencil framebuffer fetch, where a perma-switch is troublesome (for example in combination with read-only depth/stencil feedback loops). Bug: angleproject:352364582 Change-Id: I31221cf22a28d58b9b2bf188e9c0b786cd0fe3d2 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5923120 Reviewed-by: Yuxin Hu <yuxinhu@google.com> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com>