Refactor position computation to enable device space "nudge"

src/gpu/effects/GrBitmapTextGeoProc.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrBitmapTextGeoProc.h"
 #include "GrInvariantOutput.h"
 #include "GrTexture.h"
 #include "gl/GrGLProcessor.h"
 #include "gl/GrGLSL.h"
 #include "gl/GrGLTexture.h"
 #include "gl/GrGLGeometryProcessor.h"
 #include "gl/builders/GrGLProgramBuilder.h"
 
 struct BitmapTextBatchTracker {
     GrGPInput fInputColorType;
     GrColor fColor;
     bool fUsesLocalCoords;
 };
 
 class GrGLBitmapTextGeoProc : public GrGLGeometryProcessor {
 public:
     GrGLBitmapTextGeoProc(const GrGeometryProcessor&, const GrBatchTracker&)
         : fColor(GrColor_ILLEGAL) {}
 
-    void onEmitCode(EmitArgs& args) SK_OVERRIDE {
+    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE{
         const GrBitmapTextGeoProc& cte = args.fGP.cast<GrBitmapTextGeoProc>();
         const BitmapTextBatchTracker& local = args.fBT.cast<BitmapTextBatchTracker>();
 
         GrGLGPBuilder* pb = args.fPB;
         GrGLVertexBuilder* vsBuilder = pb->getVertexShaderBuilder();
 
         // emit attributes
         vsBuilder->emitAttributes(cte);
 
         GrGLVertToFrag v(kVec2f_GrSLType);
         pb->addVarying("TextureCoords", &v);
         vsBuilder->codeAppendf("%s = %s;", v.vsOut(), cte.inTextureCoords()->fName);
 
         // Setup pass through color
         this->setupColorPassThrough(pb, local.fInputColorType, args.fOutputColor, cte.inColor(),
                                     &fColorUniform);
 
         // setup uniform viewMatrix
         this->addUniformViewMatrix(pb);
 
         // Setup position
-        vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);",  this->position(), this->uViewM(),
-                               cte.inPosition()->fName);
+        SetupPosition(vsBuilder, gpArgs, cte.inPosition()->fName,
+                      cte.viewMatrix(), this->uViewM());
 
         // emit transforms
-        this->emitTransforms(args.fPB,  this->position(), cte.inPosition()->fName,
+        this->emitTransforms(args.fPB, gpArgs->fPositionVar, cte.inPosition()->fName,
                              cte.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
         GrGLGPFragmentBuilder* fsBuilder = pb->getFragmentShaderBuilder();
         fsBuilder->codeAppendf("%s = ", args.fOutputCoverage);
         fsBuilder->appendTextureLookup(args.fSamplers[0], v.fsIn(), kVec2f_GrSLType);
         fsBuilder->codeAppend(";");
     }
 
     virtual void setData(const GrGLProgramDataManager& pdman,
                          const GrPrimitiveProcessor& gp,
@@ skipping 14 matching lines @@
                               const GrGLCaps&,
                               GrProcessorKeyBuilder* b) {
         const BitmapTextBatchTracker& local = bt.cast<BitmapTextBatchTracker>();
         // We have to put the optional vertex attribute as part of the key.  See the comment
         // on addVertexAttrib.
         // TODO When we have deferred geometry we can fix this
         const GrBitmapTextGeoProc& gp = proc.cast<GrBitmapTextGeoProc>();
         uint32_t key = 0;
         key |= SkToBool(gp.inColor()) ? 0x1 : 0x0;
         key |= local.fUsesLocalCoords && proc.localMatrix().hasPerspective() ? 0x2 : 0x0;
+        key |= ComputePosKey(gp.viewMatrix()) << 2;
         b->add32(local.fInputColorType << 16 | key);
     }
 
 private:
     GrColor fColor;
     UniformHandle fColorUniform;
 
     typedef GrGLGeometryProcessor INHERITED;
 };
 
@@ skipping 82 matching lines @@
         kTileModes[random->nextULessThan(SK_ARRAY_COUNT(kTileModes))],
         kTileModes[random->nextULessThan(SK_ARRAY_COUNT(kTileModes))],
     };
     GrTextureParams params(tileModes, random->nextBool() ? GrTextureParams::kBilerp_FilterMode :
                                                            GrTextureParams::kNone_FilterMode);
 
     return GrBitmapTextGeoProc::Create(GrRandomColor(random), textures[texIdx], params,
                                        random->nextBool(), random->nextBool(),
                                        GrProcessorUnitTest::TestMatrix(random));
 }