commit 7193586dab17e4a190b68259cb9876abbd06b843
author Ethan Nicholas <ethannicholas@google.com> Wed Feb 06 09:25:40 2019 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Wed Feb 06 15:32:52 2019 +0000
tree c006bd523a38d67371a25179284abf78a1f19a13
parent 79bd872596474bdcef023028ccf5951679d96f92

fixed SRGB effect color accuracy

Bug: skia:
Change-Id: I8715357f053fbfab73e9cbe674dd082aabe77329
Reviewed-on: https://skia-review.googlesource.com/c/189841
Reviewed-by: Ethan Nicholas <ethannicholas@google.com>
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>

src/gpu/effects/GrSRGBEffect.cpp

diff --git a/src/gpu/effects/GrSRGBEffect.cpp b/src/gpu/effects/GrSRGBEffect.cpp
index 3338361..8fbe1dd 100644
--- a/src/gpu/effects/GrSRGBEffect.cpp
+++ b/src/gpu/effects/GrSRGBEffect.cpp
@@ -45,19 +45,20 @@
 
         // Mali Bifrost uses fp16 for mediump. Making the intermediate color variable highp causes
         // calculations to be performed with sufficient precision.
-        fragBuilder->codeAppendf("half4 color = %s;", args.fInputColor);
+        fragBuilder->codeAppendf("float4 color = %s;", args.fInputColor);
         if (srgbe.alpha() == GrSRGBEffect::Alpha::kPremul) {
-            fragBuilder->codeAppendf("half nonZeroAlpha = max(color.a, 0.00001);");
-            fragBuilder->codeAppendf("color = half4(color.rgb / nonZeroAlpha, color.a);");
+            fragBuilder->codeAppendf("float nonZeroAlpha = max(color.a, 0.00001);");
+            fragBuilder->codeAppendf("color = float4(color.rgb / nonZeroAlpha, color.a);");
         }
-        fragBuilder->codeAppendf("color = half4(%s(color.r), %s(color.g), %s(color.b), color.a);",
-                                    srgbFuncName.c_str(),
-                                    srgbFuncName.c_str(),
-                                    srgbFuncName.c_str());
+        fragBuilder->codeAppendf("color = float4(%s(half(color.r)), %s(half(color.g)), "
+                                 "%s(half(color.b)), color.a);",
+                                 srgbFuncName.c_str(),
+                                 srgbFuncName.c_str(),
+                                 srgbFuncName.c_str());
         if (srgbe.alpha() == GrSRGBEffect::Alpha::kPremul) {
-            fragBuilder->codeAppendf("color = half4(color.rgb, 1) * color.a;");
+            fragBuilder->codeAppendf("color = float4(color.rgb, 1) * color.a;");
         }
-        fragBuilder->codeAppendf("%s = color;", args.fOutputColor);
+        fragBuilder->codeAppendf("%s = half4(color);", args.fOutputColor);
     }
 
     static inline void GenKey(const GrProcessor& processor, const GrShaderCaps&,