commit c8ece3d5f877d67114dfda51a336dfdf7838095a
author Chris Dalton <csmartdalton@google.com> Mon Jul 30 15:03:45 2018 -0600
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Tue Jul 31 16:19:12 2018 +0000
tree b7ee09e0120e9f17e34aa3af8e0bcdf1f6325dea
parent 5cfb04a68432ffa8015b9277cc8a126472d664ea

Don't use glFrontFace

This is an exploratory commit to see if glFrontFace is the cause of
a recent perf regression. Instead we invert gl_FrontFacing in SkSL.

Bug: skia:
Change-Id: Ida6f6435785e814c089ad34ba2f32793c4ac23c4
Reviewed-on: https://skia-review.googlesource.com/144410
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>

src/sksl/SkSLGLSLCodeGenerator.cpp

diff --git a/src/sksl/SkSLGLSLCodeGenerator.cpp b/src/sksl/SkSLGLSLCodeGenerator.cpp
index f0c97a3..62cfbae 100644
--- a/src/sksl/SkSLGLSLCodeGenerator.cpp
+++ b/src/sksl/SkSLGLSLCodeGenerator.cpp
@@ -690,7 +690,7 @@
             this->writeFragCoord();
             break;
         case SK_CLOCKWISE_BUILTIN:
-            this->write("gl_FrontFacing");
+            this->write(fProgram.fSettings.fFlipY ? "(!gl_FrontFacing)" : "gl_FrontFacing");
             break;
         case SK_VERTEXID_BUILTIN:
             this->write("gl_VertexID");