kc3-lang/angle

2020-08-14T22:48:15

Feedback Loop Redesign 2/3: Track bound FBOs in Texture. Currently we track feedback loops by counting the times a Texture is bound as a sampler or image in a particular context. This is a bit tricky because Texture bindings change frequently. Relative to the number of times we need to check for a feedback loop this causes excess overhead. Usually Framebuffers have a low number of Textures bound (in many cases just 1). And Textures aren't usually bound to many different FBOs. So instead of counting the number of times a Texture is bound as a sampler or image we will track the Framebuffers that the Texture is bound to. This CL adds a small vector class to gl::Texture which tracks all the Framebufer Serials of its bound Framebuffers. We can use this set to quickly check if there's any potential feedback loop between the a FBO and this Texture. We also update the feedback loop check to use this new method. We will be able to remove the old counting method when we switch the Vulkan feedback loop handling to use the new tracking in this CL. Bug: angleproject:4500 Bug: angleproject:4959 Change-Id: I84a2f0ed8480d1da63d5879e0e56a8be4af4e735 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2358850 Reviewed-by: Tobin Ehlis <tobine@google.com> Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com> Reviewed-by: Jonah Ryan-Davis <jonahr@google.com> Commit-Queue: Jamie Madill <jmadill@chromium.org>