Commit 6af0c03f9eadf548a42623a4692565b577142141
2021-02-25T18:15:21
Vulkan: Always write to swapchain alpha channel This fixes an issue with the "Ragnarok M: Eternal Love" game, which uses a GL_RGB8 format for its window, which is actually backed by a GL_RGBA8 format (a.k.a. "emulated alpha"). The game does no explicit clear per frame. Therefore, ANGLE selects a render pass loadOp=DONT_CARE, which leaves the alpha channel undefined (0.0 on a Pixel 4 XL). That causes SurfaceFlinger to show (blend or alternate vsyncs) what should have been covered up by the game (e.g. the Android launcher and live wallpaper). The solution is to prevent loadOp=DONT_CARE for emulated alpha. Test: ClearTest.ChangeFramebufferAttachmentFromRGBAtoRGB Test: dEQP-GLES2.functional.fbo.render.stencil_clear.tex2d_rgb_stencil_index8 Bug: b/180139027 Change-Id: Ied97b57c93d41326cb3294ff246691e09f316791 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2704949 Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Tim Van Patten <timvp@google.com> Commit-Queue: Ian Elliott <ianelliott@google.com>