Refactor position computation to enable device space "nudge"

src/gpu/GrDefaultGeoProcFactory.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 "GrDefaultGeoProcFactory.h"
 
 #include "GrDrawState.h"
@@ skipping 65 matching lines @@
                                 theirs.fInputColorType, theirs.fColor) &&
                CanCombineOutput(mine.fInputCoverageType, mine.fCoverage,
                                 theirs.fInputCoverageType, theirs.fCoverage);
     }
 
     class GLProcessor : public GrGLGeometryProcessor {
     public:
         GLProcessor(const GrGeometryProcessor& gp, const GrBatchTracker&)
             : fColor(GrColor_ILLEGAL), fCoverage(0xff) {}
 
-        void onEmitCode(EmitArgs& args) SK_OVERRIDE {
+        void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE {
             const DefaultGeoProc& gp = args.fGP.cast<DefaultGeoProc>();
             GrGLGPBuilder* pb = args.fPB;
-            GrGLVertexBuilder* vs = pb->getVertexShaderBuilder();
+            GrGLVertexBuilder* vsBuilder = pb->getVertexShaderBuilder();
             GrGLGPFragmentBuilder* fs = args.fPB->getFragmentShaderBuilder();
             const BatchTracker& local = args.fBT.cast<BatchTracker>();
 
             // emit attributes
-            vs->emitAttributes(gp);
+            vsBuilder->emitAttributes(gp);
 
             // Setup pass through color
             this->setupColorPassThrough(pb, local.fInputColorType, args.fOutputColor, gp.inColor(),
                                         &fColorUniform);
 
             // setup uniform viewMatrix
             this->addUniformViewMatrix(pb);
 
             // Setup position
-            vs->codeAppendf("%s = %s * vec3(%s, 1);",  this->position(), this->uViewM(),
-                            gp.inPosition()->fName);
+            SetupPosition(vsBuilder, gpArgs, gp.inPosition()->fName,
+                          gp.viewMatrix(), this->uViewM());
 
             if (gp.inLocalCoords()) {
                 // emit transforms with explicit local coords
-                this->emitTransforms(pb,  this->position(), gp.inLocalCoords()->fName,
+                this->emitTransforms(pb, gpArgs->fPositionVar, gp.inLocalCoords()->fName,
                                      gp.localMatrix(), args.fTransformsIn, args.fTransformsOut);
             } else {
                 // emit transforms with position
-                this->emitTransforms(pb,  this->position(), gp.inPosition()->fName,
+                this->emitTransforms(pb, gpArgs->fPositionVar, gp.inPosition()->fName,
                                      gp.localMatrix(), args.fTransformsIn, args.fTransformsOut);
             }
 
             // Setup coverage as pass through
             if (kUniform_GrGPInput == local.fInputCoverageType) {
                 const char* fragCoverage;
                 fCoverageUniform = pb->addUniform(GrGLProgramBuilder::kFragment_Visibility,
                                                   kFloat_GrSLType,
                                                   kDefault_GrSLPrecision,
                                                   "Coverage",
@@ skipping 11 matching lines @@
 
         static inline void GenKey(const GrGeometryProcessor& gp,
                                   const GrBatchTracker& bt,
                                   const GrGLCaps&,
                                   GrProcessorKeyBuilder* b) {
             const DefaultGeoProc& def = gp.cast<DefaultGeoProc>();
             const BatchTracker& local = bt.cast<BatchTracker>();
             uint32_t key = def.fFlags;
             key |= local.fInputColorType << 8 | local.fInputCoverageType << 16;
             key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 << 24 : 0x0;
+            key |= ComputePosKey(gp.viewMatrix()) << 25;
             b->add32(key);
         }
 
         virtual void setData(const GrGLProgramDataManager& pdman,
                              const GrPrimitiveProcessor& gp,
                              const GrBatchTracker& bt) SK_OVERRIDE {
             this->setUniformViewMatrix(pdman, gp.viewMatrix());
 
             const BatchTracker& local = bt.cast<BatchTracker>();
             if (kUniform_GrGPInput == local.fInputColorType && local.fColor != fColor) {
@@ skipping 127 matching lines @@
                                                            const SkMatrix& localMatrix,
                                                            bool opaqueVertexColors,
                                                            uint8_t coverage) {
     return DefaultGeoProc::Create(gpTypeFlags,
                                   color,
                                   viewMatrix,
                                   localMatrix,
                                   opaqueVertexColors,
                                   coverage);
 }