commit 060d9820364b0cf09c7eb3bda449f24c3dcba2e2
author Jim Van Verth <jvanverth@google.com> Thu May 04 09:58:17 2017 -0400
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Thu May 04 14:28:28 2017 +0000
tree c839d2c3129f90c281d3b0f2c642cf160675b056
parent db711c982bfaa805d2de5a253c55a680c30189e0

Combine the ambient and spot alphas into the base color
for geometric shadows. 

This matches the analytic shadow approach better, and
is color space invariant.
Also includes cleanup in SampleAndroidShadows.

Bug: skia:6546
Change-Id: I7a7cd060420dae741f967334c8b19542a14f0bcf
Reviewed-on: https://skia-review.googlesource.com/15228
Commit-Queue: Jim Van Verth <jvanverth@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>

src/gpu/effects/GrBlurredEdgeFragmentProcessor.cpp

diff --git a/src/gpu/effects/GrBlurredEdgeFragmentProcessor.cpp b/src/gpu/effects/GrBlurredEdgeFragmentProcessor.cpp
index 95b08d2..a37c173 100644
--- a/src/gpu/effects/GrBlurredEdgeFragmentProcessor.cpp
+++ b/src/gpu/effects/GrBlurredEdgeFragmentProcessor.cpp
@@ -23,7 +23,7 @@
         fragBuilder->codeAppendf("vec4 color = %s;", args.fInputColor);
         if (!args.fGpImplementsDistanceVector) {
             fragBuilder->codeAppendf("// assuming interpolant is set in vertex colors\n");
-            fragBuilder->codeAppendf("float factor = 1.0 - color.b;");
+            fragBuilder->codeAppendf("float factor = 1.0 - color.a;");
         } else {
             fragBuilder->codeAppendf("// using distance to edge to compute interpolant\n");
             fragBuilder->codeAppend("float radius = color.r*256.0*64.0 + color.g*64.0;");
@@ -37,14 +37,10 @@
                 fragBuilder->codeAppend("factor = exp(-factor * factor * 4.0) - 0.018;");
                 break;
             case GrBlurredEdgeFP::kSmoothstep_Mode:
-                fragBuilder->codeAppend("factor = smoothstep(factor, 0.0, 1.0);");
+                fragBuilder->codeAppend("factor = smoothstep(1.0, 0.0, factor);");
                 break;
         }
-        if (!args.fGpImplementsDistanceVector) {
-            fragBuilder->codeAppendf("%s = vec4(factor*color.g);", args.fOutputColor);
-        } else {
-            fragBuilder->codeAppendf("%s = vec4(factor*color.a);", args.fOutputColor);
-        }
+        fragBuilder->codeAppendf("%s = vec4(factor);", args.fOutputColor);
     }
 
 protected: