Fix gpu lcd blending to semi-correctly handle alpha coverage

Bug: skia:6606
Change-Id: I16ccd97f5d047eb7fddfed5310bf669e7435ccdd
Reviewed-on: https://skia-review.googlesource.com/17370
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>

1 files changed, 11 insertions, 3 deletions

diff --git a/src/gpu/GrXferProcessor.cpp b/src/gpu/GrXferProcessor.cpp
index 27c8a963e4..8c0568bcae 100644
--- a/src/gpu/GrXferProcessor.cpp
+++ b/src/gpu/GrXferProcessor.cpp
@@ -9,11 +9,16 @@
 #include "GrPipeline.h"
 #include "gl/GrGLCaps.h"
 
-GrXferProcessor::GrXferProcessor() : fWillReadDstColor(false), fDstReadUsesMixedSamples(false) {}
+GrXferProcessor::GrXferProcessor()
+        : fWillReadDstColor(false)
+        , fDstReadUsesMixedSamples(false)
+        , fIsLCD(false) {}
 
-GrXferProcessor::GrXferProcessor(bool willReadDstColor, bool hasMixedSamples)
+GrXferProcessor::GrXferProcessor(bool willReadDstColor, bool hasMixedSamples,
+                                 GrProcessorAnalysisCoverage coverage)
         : fWillReadDstColor(willReadDstColor)
-        , fDstReadUsesMixedSamples(willReadDstColor && hasMixedSamples) {}
+        , fDstReadUsesMixedSamples(willReadDstColor && hasMixedSamples)
+        , fIsLCD(GrProcessorAnalysisCoverage::kLCD == coverage) {}
 
 bool GrXferProcessor::hasSecondaryOutput() const {
     if (!this->willReadDstColor()) {
@@ -45,6 +50,9 @@ void GrXferProcessor::getGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorK
             key |= 0x8;
         }
     }
+    if (fIsLCD) {
+        key |= 0x10;
+    }
     b->add32(key);
     this->onGetGLSLProcessorKey(caps, b);
 }