GrFP can express distance vector field req., program builder declares variable for it

src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLSLFragmentShaderBuilder.h"
 #include "GrRenderTarget.h"
 #include "GrRenderTargetPriv.h"
@@ skipping 171 matching lines @@
             this->codePrependf("\t%svec4 %s = vec4(%s.x, %s - %s.y, 1.0, 1.0);\n",
                                precision, kCoordName, kTempName, rtHeightName, kTempName);
             this->codePrependf("%svec2 %s = gl_FragCoord.xy;", precision, kTempName);
             fSetupFragPosition = true;
         }
         SkASSERT(fProgramBuilder->fUniformHandles.fRTHeightUni.isValid());
         return kCoordName;
     }
 }
 
+bool GrGLSLFragmentShaderBuilder::hasDistanceVectorOutput() const {
+    return !fDistanceVectorOutput.isEmpty();
+}
+
+void GrGLSLFragmentShaderBuilder::enableDistanceVector(const SkString& name) {
+    SkASSERT(!this->hasDistanceVectorOutput());
+    fDistanceVectorOutput = name;
+}
+
+const char* GrGLSLFragmentShaderBuilder::distanceVectorName() const {
+    SkASSERT(this->hasDistanceVectorOutput());
+    return fDistanceVectorOutput.c_str();
+}
+
 void GrGLSLFragmentShaderBuilder::appendOffsetToSample(const char* sampleIdx, Coordinates coords) {
     SkASSERT(fProgramBuilder->header().fSamplePatternKey);
     SkDEBUGCODE(fUsedProcessorFeatures |= GrProcessor::kSampleLocations_RequiredFeature);
     if (kTopLeft_GrSurfaceOrigin == this->getSurfaceOrigin()) {
         // With a top left origin, device and window space are equal, so we only use device coords.
         coords = kSkiaDevice_Coordinates;
     }
     this->codeAppendf("%s[%s]", sample_offset_array_name(coords), sampleIdx);
     fUsedSampleOffsetArrays |= (1 << coords);
 }
@@ skipping 183 matching lines @@
     fMangleString.appendf("_c%d", fSubstageIndices[fSubstageIndices.count() - 2]);
 }
 
 void GrGLSLFragmentShaderBuilder::onAfterChildProcEmitCode() {
     SkASSERT(fSubstageIndices.count() >= 2);
     fSubstageIndices.pop_back();
     fSubstageIndices.back()++;
     int removeAt = fMangleString.findLastOf('_');
     fMangleString.remove(removeAt, fMangleString.size() - removeAt);
 }