Refactor position computation to enable device space "nudge"

To match raster's handling of BW geometry we want to be able to perform a device space "nudge" on all geometry. This CL sets us up to be able to do that in GrGLVertexBuilder::transformToNormalizedDeviceSpace.

BUG=423834
TBR=bsalomon@google.com

Review URL: https://codereview.chromium.org/854013002

13 files changed, 201 insertions, 125 deletions

diff --git a/src/gpu/GrAAConvexPathRenderer.cpp b/src/gpu/GrAAConvexPathRenderer.cpp
index c589f8cb1d..27cc8aa3be 100644
--- a/src/gpu/GrAAConvexPathRenderer.cpp
+++ b/src/gpu/GrAAConvexPathRenderer.cpp
@@ -535,7 +535,7 @@ public:
                     const GrBatchTracker&)
             : fColor(GrColor_ILLEGAL) {}
 
-        void onEmitCode(EmitArgs& args) SK_OVERRIDE {
+        void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE {
             const QuadEdgeEffect& qe = args.fGP.cast<QuadEdgeEffect>();
             GrGLGPBuilder* pb = args.fPB;
             GrGLVertexBuilder* vsBuilder = pb->getVertexShaderBuilder();
@@ -557,11 +557,11 @@ public:
             this->addUniformViewMatrix(pb);
 
             // Setup position
-            vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);",  this->position(), this->uViewM(),
-                                   qe.inPosition()->fName);
+            SetupPosition(vsBuilder, gpArgs, qe.inPosition()->fName,
+                          qe.viewMatrix(), this->uViewM());
 
             // emit transforms
-            this->emitTransforms(args.fPB,  this->position(), qe.inPosition()->fName,
+            this->emitTransforms(args.fPB, gpArgs->fPositionVar, qe.inPosition()->fName,
                                  qe.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
             GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
@@ -594,8 +594,10 @@ public:
                                   const GrGLCaps&,
                                   GrProcessorKeyBuilder* b) {
             const BatchTracker& local = bt.cast<BatchTracker>();
-            b->add32((local.fInputColorType << 16) |
-                     (local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 : 0x0));
+            uint32_t key = local.fInputColorType << 16;
+            key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 : 0x0;
+            key |= ComputePosKey(gp.viewMatrix()) << 1;
+            b->add32(key);
         }
 
         virtual void setData(const GrGLProgramDataManager& pdman,
diff --git a/src/gpu/GrDefaultGeoProcFactory.cpp b/src/gpu/GrDefaultGeoProcFactory.cpp
index 25c34ed929..3e32e65c62 100644
--- a/src/gpu/GrDefaultGeoProcFactory.cpp
+++ b/src/gpu/GrDefaultGeoProcFactory.cpp
@@ -83,15 +83,15 @@ 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(),
@@ -101,16 +101,16 @@ public:
             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);
             }
 
@@ -142,6 +142,7 @@ public:
             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);
         }
 
diff --git a/src/gpu/GrGeometryProcessor.cpp b/src/gpu/GrGeometryProcessor.cpp
index 344dccc731..662f28f386 100644
--- a/src/gpu/GrGeometryProcessor.cpp
+++ b/src/gpu/GrGeometryProcessor.cpp
@@ -163,13 +163,13 @@ void GrGLPrimitiveProcessor::setUniformViewMatrix(const GrGLProgramDataManager&
 
 void GrGLGeometryProcessor::emitCode(EmitArgs& args) {
     GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
-    vsBuilder->codeAppendf("vec3 %s;", this->position());
-    this->onEmitCode(args);
-    vsBuilder->transformToNormalizedDeviceSpace(this->position());
+    GrGPArgs gpArgs;
+    this->onEmitCode(args, &gpArgs);
+    vsBuilder->transformToNormalizedDeviceSpace(gpArgs.fPositionVar);
 }
 
 void GrGLGeometryProcessor::emitTransforms(GrGLGPBuilder* pb,
-                                           const char* position,
+                                           const GrShaderVar& posVar,
                                            const char* localCoords,
                                            const SkMatrix& localMatrix,
                                            const TransformsIn& tin,
@@ -214,9 +214,19 @@ void GrGLGeometryProcessor::emitTransforms(GrGLGPBuilder* pb,
             // varying = matrix * coords (logically)
             if (kDevice_GrCoordSet == coordType) {
                 if (kVec2f_GrSLType == varyingType) {
-                    vb->codeAppendf("%s = (%s * %s).xy;", v.vsOut(), uniName, position);
+                    if (kVec2f_GrSLType == posVar.getType()) {
+                        vb->codeAppendf("%s = (%s * vec3(%s, 1)).xy;",
+                                        v.vsOut(), uniName, posVar.c_str());
+                    } else {
+                        vb->codeAppendf("%s = (%s * %s).xy;", v.vsOut(), uniName, posVar.c_str());
+                    }
                 } else {
-                    vb->codeAppendf("%s = %s * %s;", v.vsOut(), uniName, position);
+                    if (kVec2f_GrSLType == posVar.getType()) {
+                        vb->codeAppendf("%s = %s * vec3(%s, 1);",
+                                        v.vsOut(), uniName, posVar.c_str());
+                    } else {
+                        vb->codeAppendf("%s = %s * %s;", v.vsOut(), uniName, posVar.c_str());
+                    }
                 }
             } else {
                 if (kVec2f_GrSLType == varyingType) {
@@ -247,6 +257,28 @@ GrGLGeometryProcessor::setTransformData(const GrPrimitiveProcessor* primProc,
     }
 }
 
+void GrGLGeometryProcessor::SetupPosition(GrGLVertexBuilder* vsBuilder,
+                                          GrGPArgs* gpArgs,
+                                          const char* posName,
+                                          const SkMatrix& mat,
+                                          const char* matName) {
+    if (mat.isIdentity()) {
+        gpArgs->fPositionVar.set(kVec2f_GrSLType, "pos2");
+
+        vsBuilder->codeAppendf("vec2 %s = %s;", gpArgs->fPositionVar.c_str(), posName);
+    } else if (!mat.hasPerspective()) {
+        gpArgs->fPositionVar.set(kVec2f_GrSLType, "pos2");
+
+        vsBuilder->codeAppendf("vec2 %s = vec2(%s * vec3(%s, 1));",
+                               gpArgs->fPositionVar.c_str(), matName, posName);
+    } else {
+        gpArgs->fPositionVar.set(kVec3f_GrSLType, "pos3");
+
+        vsBuilder->codeAppendf("vec3 %s = %s * vec3(%s, 1);",
+                               gpArgs->fPositionVar.c_str(), matName, posName);
+    }
+}
+
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 #include "gl/GrGLGpu.h"
diff --git a/src/gpu/GrGeometryProcessor.h b/src/gpu/GrGeometryProcessor.h
index 43b6a7e31a..736c515e88 100644
--- a/src/gpu/GrGeometryProcessor.h
+++ b/src/gpu/GrGeometryProcessor.h
@@ -220,7 +220,7 @@ protected:
 private:
     virtual bool hasExplicitLocalCoords() const = 0;
 
-    SkMatrix fViewMatrix;
+    const SkMatrix fViewMatrix;
     SkMatrix fLocalMatrix;
 
     typedef GrProcessor INHERITED;
diff --git a/src/gpu/GrOvalRenderer.cpp b/src/gpu/GrOvalRenderer.cpp
index 2f8af8d175..a35d70859a 100644
--- a/src/gpu/GrOvalRenderer.cpp
+++ b/src/gpu/GrOvalRenderer.cpp
@@ -83,7 +83,7 @@ public:
                     const GrBatchTracker&)
             : fColor(GrColor_ILLEGAL) {}
 
-        void onEmitCode(EmitArgs& args) SK_OVERRIDE {
+        void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE{
             const CircleEdgeEffect& ce = args.fGP.cast<CircleEdgeEffect>();
             GrGLGPBuilder* pb = args.fPB;
             const BatchTracker& local = args.fBT.cast<BatchTracker>();
@@ -104,11 +104,11 @@ public:
             this->addUniformViewMatrix(pb);
 
             // Setup position
-            vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);",  this->position(), this->uViewM(),
-                                   ce.inPosition()->fName);
+            SetupPosition(vsBuilder, gpArgs, ce.inPosition()->fName,
+                          ce.viewMatrix(), this->uViewM());
 
             // emit transforms
-            this->emitTransforms(args.fPB,  this->position(), ce.inPosition()->fName,
+            this->emitTransforms(args.fPB, gpArgs->fPositionVar, ce.inPosition()->fName,
                                  ce.localMatrix(), args.fTransformsIn, args.fTransformsOut);;
 
             GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
@@ -123,14 +123,15 @@ public:
             fsBuilder->codeAppendf("%s = vec4(edgeAlpha);", args.fOutputCoverage);
         }
 
-        static void GenKey(const GrGeometryProcessor& processor,
+        static void GenKey(const GrGeometryProcessor& gp,
                            const GrBatchTracker& bt,
                            const GrGLCaps&,
                            GrProcessorKeyBuilder* b) {
             const BatchTracker& local = bt.cast<BatchTracker>();
-            const CircleEdgeEffect& circleEffect = processor.cast<CircleEdgeEffect>();
+            const CircleEdgeEffect& circleEffect = gp.cast<CircleEdgeEffect>();
             uint16_t key = circleEffect.isStroked() ? 0x1 : 0x0;
-            key |= local.fUsesLocalCoords && processor.localMatrix().hasPerspective() ? 0x2 : 0x0;
+            key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x2 : 0x0;
+            key |= ComputePosKey(gp.viewMatrix()) << 2;
             b->add32(key << 16 | local.fInputColorType);
         }
 
@@ -259,7 +260,7 @@ public:
                     const GrBatchTracker&)
             : fColor(GrColor_ILLEGAL) {}
 
-        void onEmitCode(EmitArgs& args) SK_OVERRIDE {
+        void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE{
             const EllipseEdgeEffect& ee = args.fGP.cast<EllipseEdgeEffect>();
             GrGLGPBuilder* pb = args.fPB;
             const BatchTracker& local = args.fBT.cast<BatchTracker>();
@@ -286,11 +287,11 @@ public:
             this->addUniformViewMatrix(pb);
 
             // Setup position
-            vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);", this->position(), this->uViewM(),
-                                   ee.inPosition()->fName);
+            SetupPosition(vsBuilder, gpArgs, ee.inPosition()->fName,
+                          ee.viewMatrix(), this->uViewM());
 
             // emit transforms
-            this->emitTransforms(args.fPB, this->position(), ee.inPosition()->fName,
+            this->emitTransforms(args.fPB, gpArgs->fPositionVar, ee.inPosition()->fName,
                                  ee.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
             // for outer curve
@@ -320,14 +321,15 @@ public:
             fsBuilder->codeAppendf("%s = vec4(edgeAlpha);", args.fOutputCoverage);
         }
 
-        static void GenKey(const GrGeometryProcessor& processor,
+        static void GenKey(const GrGeometryProcessor& gp,
                            const GrBatchTracker& bt,
                            const GrGLCaps&,
                            GrProcessorKeyBuilder* b) {
             const BatchTracker& local = bt.cast<BatchTracker>();
-            const EllipseEdgeEffect& ellipseEffect = processor.cast<EllipseEdgeEffect>();
+            const EllipseEdgeEffect& ellipseEffect = gp.cast<EllipseEdgeEffect>();
             uint16_t key = ellipseEffect.isStroked() ? 0x1 : 0x0;
-            key |= local.fUsesLocalCoords && processor.localMatrix().hasPerspective() ? 0x2 : 0x0;
+            key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x2 : 0x0;
+            key |= ComputePosKey(gp.viewMatrix()) << 2;
             b->add32(key << 16 | local.fInputColorType);
         }
 
@@ -463,7 +465,7 @@ public:
                     const GrBatchTracker&)
             : fColor(GrColor_ILLEGAL) {}
 
-        void onEmitCode(EmitArgs& args) SK_OVERRIDE {
+        void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE{
             const DIEllipseEdgeEffect& ee = args.fGP.cast<DIEllipseEdgeEffect>();
             GrGLGPBuilder* pb = args.fPB;
             const BatchTracker& local = args.fBT.cast<BatchTracker>();
@@ -490,11 +492,11 @@ public:
             this->addUniformViewMatrix(pb);
 
             // Setup position
-            vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);", this->position(), this->uViewM(),
-                                   ee.inPosition()->fName);
+            SetupPosition(vsBuilder, gpArgs, ee.inPosition()->fName,
+                          ee.viewMatrix(), this->uViewM());
 
             // emit transforms
-            this->emitTransforms(args.fPB, this->position(), ee.inPosition()->fName,
+            this->emitTransforms(args.fPB, gpArgs->fPositionVar, ee.inPosition()->fName,
                                  ee.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
             GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
@@ -538,15 +540,15 @@ public:
             fsBuilder->codeAppendf("%s = vec4(edgeAlpha);", args.fOutputCoverage);
         }
 
-        static void GenKey(const GrGeometryProcessor& processor,
+        static void GenKey(const GrGeometryProcessor& gp,
                            const GrBatchTracker& bt,
                            const GrGLCaps&,
                            GrProcessorKeyBuilder* b) {
             const BatchTracker& local = bt.cast<BatchTracker>();
-            const DIEllipseEdgeEffect& ellipseEffect = processor.cast<DIEllipseEdgeEffect>();
+            const DIEllipseEdgeEffect& ellipseEffect = gp.cast<DIEllipseEdgeEffect>();
             uint16_t key = ellipseEffect.getMode();
-            key |= local.fUsesLocalCoords && processor.localMatrix().hasPerspective() ? 0x1 << 8 :
-                                                                                        0x0;
+            key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 << 8 : 0x0;
+            key |= ComputePosKey(gp.viewMatrix()) << 9;
             b->add32(key << 16 | local.fInputColorType);
         }
 
diff --git a/src/gpu/effects/GrBezierEffect.cpp b/src/gpu/effects/GrBezierEffect.cpp
index b8e4c0cb18..1c6d469033 100644
--- a/src/gpu/effects/GrBezierEffect.cpp
+++ b/src/gpu/effects/GrBezierEffect.cpp
@@ -24,7 +24,7 @@ public:
     GrGLConicEffect(const GrGeometryProcessor&,
                     const GrBatchTracker&);
 
-    void onEmitCode(EmitArgs&) SK_OVERRIDE;
+    void onEmitCode(EmitArgs&, GrGPArgs*) SK_OVERRIDE;
 
     static inline void GenKey(const GrGeometryProcessor&,
                               const GrBatchTracker&,
@@ -66,7 +66,7 @@ GrGLConicEffect::GrGLConicEffect(const GrGeometryProcessor& processor,
     fEdgeType = ce.getEdgeType();
 }
 
-void GrGLConicEffect::onEmitCode(EmitArgs& args) {
+void GrGLConicEffect::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
     GrGLGPBuilder* pb = args.fPB;
     GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
     const GrConicEffect& gp = args.fGP.cast<GrConicEffect>();
@@ -87,11 +87,10 @@ void GrGLConicEffect::onEmitCode(EmitArgs& args) {
     this->addUniformViewMatrix(pb);
 
     // Setup position
-    vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);", this->position(), this->uViewM(),
-                           gp.inPosition()->fName);
+    SetupPosition(vsBuilder, gpArgs, gp.inPosition()->fName, gp.viewMatrix(), this->uViewM());
 
     // emit transforms with position
-    this->emitTransforms(pb, this->position(), gp.inPosition()->fName, gp.localMatrix(),
+    this->emitTransforms(pb, gpArgs->fPositionVar, gp.inPosition()->fName, gp.localMatrix(),
                          args.fTransformsIn, args.fTransformsOut);
 
     GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
@@ -164,16 +163,17 @@ void GrGLConicEffect::onEmitCode(EmitArgs& args) {
     }
 }
 
-void GrGLConicEffect::GenKey(const GrGeometryProcessor& processor,
+void GrGLConicEffect::GenKey(const GrGeometryProcessor& gp,
                              const GrBatchTracker& bt,
                              const GrGLCaps&,
                              GrProcessorKeyBuilder* b) {
-    const GrConicEffect& ce = processor.cast<GrConicEffect>();
+    const GrConicEffect& ce = gp.cast<GrConicEffect>();
     const ConicBatchTracker& local = bt.cast<ConicBatchTracker>();
     uint32_t key = ce.isAntiAliased() ? (ce.isFilled() ? 0x0 : 0x1) : 0x2;
     key |= kUniform_GrGPInput == local.fInputColorType ? 0x4 : 0x0;
     key |= 0xff != local.fCoverageScale ? 0x8 : 0x0;
-    key |= local.fUsesLocalCoords && processor.localMatrix().hasPerspective() ? 0x10 : 0x0;
+    key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x10 : 0x0;
+    key |= ComputePosKey(gp.viewMatrix()) << 5;
     b->add32(key);
 }
 
@@ -262,7 +262,7 @@ public:
     GrGLQuadEffect(const GrGeometryProcessor&,
                    const GrBatchTracker&);
 
-    void onEmitCode(EmitArgs&) SK_OVERRIDE;
+    void onEmitCode(EmitArgs&, GrGPArgs*) SK_OVERRIDE;
 
     static inline void GenKey(const GrGeometryProcessor&,
                               const GrBatchTracker&,
@@ -304,7 +304,7 @@ GrGLQuadEffect::GrGLQuadEffect(const GrGeometryProcessor& processor,
     fEdgeType = ce.getEdgeType();
 }
 
-void GrGLQuadEffect::onEmitCode(EmitArgs& args) {
+void GrGLQuadEffect::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
     GrGLGPBuilder* pb = args.fPB;
     GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
     const GrQuadEffect& gp = args.fGP.cast<GrQuadEffect>();
@@ -325,11 +325,10 @@ void GrGLQuadEffect::onEmitCode(EmitArgs& args) {
     this->addUniformViewMatrix(pb);
 
     // Setup position
-    vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);", this->position(), this->uViewM(),
-                           gp.inPosition()->fName);
+    SetupPosition(vsBuilder, gpArgs, gp.inPosition()->fName, gp.viewMatrix(), this->uViewM());
 
     // emit transforms with position
-    this->emitTransforms(pb, this->position(), gp.inPosition()->fName, gp.localMatrix(),
+    this->emitTransforms(pb, gpArgs->fPositionVar, gp.inPosition()->fName, gp.localMatrix(),
                          args.fTransformsIn, args.fTransformsOut);
 
     GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
@@ -388,16 +387,17 @@ void GrGLQuadEffect::onEmitCode(EmitArgs& args) {
     }
 }
 
-void GrGLQuadEffect::GenKey(const GrGeometryProcessor& processor,
+void GrGLQuadEffect::GenKey(const GrGeometryProcessor& gp,
                             const GrBatchTracker& bt,
                             const GrGLCaps&,
                             GrProcessorKeyBuilder* b) {
-    const GrQuadEffect& ce = processor.cast<GrQuadEffect>();
+    const GrQuadEffect& ce = gp.cast<GrQuadEffect>();
     const QuadBatchTracker& local = bt.cast<QuadBatchTracker>();
     uint32_t key = ce.isAntiAliased() ? (ce.isFilled() ? 0x0 : 0x1) : 0x2;
     key |= kUniform_GrGPInput == local.fInputColorType ? 0x4 : 0x0;
     key |= 0xff != local.fCoverageScale ? 0x8 : 0x0;
-    key |= local.fUsesLocalCoords && processor.localMatrix().hasPerspective() ? 0x10 : 0x0;
+    key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x10 : 0x0;
+    key |= ComputePosKey(gp.viewMatrix()) << 5;
     b->add32(key);
 }
 
@@ -486,7 +486,7 @@ public:
     GrGLCubicEffect(const GrGeometryProcessor&,
                     const GrBatchTracker&);
 
-    void onEmitCode(EmitArgs&) SK_OVERRIDE;
+    void onEmitCode(EmitArgs&, GrGPArgs*) SK_OVERRIDE;
 
     static inline void GenKey(const GrGeometryProcessor&,
                               const GrBatchTracker&,
@@ -522,7 +522,7 @@ GrGLCubicEffect::GrGLCubicEffect(const GrGeometryProcessor& processor,
     fEdgeType = ce.getEdgeType();
 }
 
-void GrGLCubicEffect::onEmitCode(EmitArgs& args) {
+void GrGLCubicEffect::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
     GrGLVertexBuilder* vsBuilder = args.fPB->getVertexShaderBuilder();
     const GrCubicEffect& gp = args.fGP.cast<GrCubicEffect>();
     const CubicBatchTracker& local = args.fBT.cast<CubicBatchTracker>();
@@ -542,11 +542,10 @@ void GrGLCubicEffect::onEmitCode(EmitArgs& args) {
     this->addUniformViewMatrix(args.fPB);
 
     // Setup position
-    vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);", this->position(), this->uViewM(),
-                           gp.inPosition()->fName);
+    SetupPosition(vsBuilder, gpArgs, gp.inPosition()->fName, gp.viewMatrix(), this->uViewM());
 
     // emit transforms with position
-    this->emitTransforms(args.fPB, this->position(), gp.inPosition()->fName, gp.localMatrix(),
+    this->emitTransforms(args.fPB, gpArgs->fPositionVar, gp.inPosition()->fName, gp.localMatrix(),
                          args.fTransformsIn, args.fTransformsOut);
 
     GrGLGPFragmentBuilder* fsBuilder = args.fPB->getFragmentShaderBuilder();
@@ -636,15 +635,16 @@ void GrGLCubicEffect::onEmitCode(EmitArgs& args) {
     fsBuilder->codeAppendf("%s = vec4(%s);", args.fOutputCoverage, edgeAlpha.c_str());
 }
 
-void GrGLCubicEffect::GenKey(const GrGeometryProcessor& processor,
+void GrGLCubicEffect::GenKey(const GrGeometryProcessor& gp,
                              const GrBatchTracker& bt,
                              const GrGLCaps&,
                              GrProcessorKeyBuilder* b) {
-    const GrCubicEffect& ce = processor.cast<GrCubicEffect>();
+    const GrCubicEffect& ce = gp.cast<GrCubicEffect>();
     const CubicBatchTracker& local = bt.cast<CubicBatchTracker>();
     uint32_t key = ce.isAntiAliased() ? (ce.isFilled() ? 0x0 : 0x1) : 0x2;
     key |= kUniform_GrGPInput == local.fInputColorType ? 0x4 : 0x8;
-    key |= local.fUsesLocalCoords && processor.localMatrix().hasPerspective() ? 0x10 : 0x0;
+    key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x10 : 0x0;
+    key |= ComputePosKey(gp.viewMatrix()) << 5;
     b->add32(key);
 }
 
diff --git a/src/gpu/effects/GrBitmapTextGeoProc.cpp b/src/gpu/effects/GrBitmapTextGeoProc.cpp
index 146fb0672f..924f7cd952 100644
--- a/src/gpu/effects/GrBitmapTextGeoProc.cpp
+++ b/src/gpu/effects/GrBitmapTextGeoProc.cpp
@@ -25,7 +25,7 @@ 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>();
 
@@ -47,11 +47,11 @@ public:
         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();
@@ -86,6 +86,7 @@ public:
         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);
     }
 
diff --git a/src/gpu/effects/GrDashingEffect.cpp b/src/gpu/effects/GrDashingEffect.cpp
index 7016ef203e..88ffad0c2e 100644
--- a/src/gpu/effects/GrDashingEffect.cpp
+++ b/src/gpu/effects/GrDashingEffect.cpp
@@ -531,7 +531,7 @@ class GLDashingCircleEffect : public GrGLGeometryProcessor {
 public:
     GLDashingCircleEffect(const GrGeometryProcessor&, const GrBatchTracker&);
 
-    void onEmitCode(EmitArgs&) SK_OVERRIDE;
+    void onEmitCode(EmitArgs&, GrGPArgs*) SK_OVERRIDE;
 
     static inline void GenKey(const GrGeometryProcessor&,
                               const GrBatchTracker&,
@@ -560,7 +560,7 @@ GLDashingCircleEffect::GLDashingCircleEffect(const GrGeometryProcessor&,
     fPrevIntervalLength = SK_ScalarMax;
 }
 
-void GLDashingCircleEffect::onEmitCode(EmitArgs& args) {
+void GLDashingCircleEffect::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
     const DashingCircleEffect& dce = args.fGP.cast<DashingCircleEffect>();
     const DashingCircleBatchTracker local = args.fBT.cast<DashingCircleBatchTracker>();
     GrGLGPBuilder* pb = args.fPB;
@@ -587,11 +587,10 @@ void GLDashingCircleEffect::onEmitCode(EmitArgs& args) {
     this->addUniformViewMatrix(pb);
 
     // Setup position
-    vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);",  this->position(), this->uViewM(),
-                           dce.inPosition()->fName);
+    SetupPosition(vsBuilder, gpArgs, dce.inPosition()->fName, dce.viewMatrix(), this->uViewM());
 
     // emit transforms
-    this->emitTransforms(args.fPB,  this->position(), dce.inPosition()->fName, dce.localMatrix(),
+    this->emitTransforms(args.fPB, gpArgs->fPositionVar, dce.inPosition()->fName, dce.localMatrix(),
                          args.fTransformsIn, args.fTransformsOut);
 
     // transforms all points so that we can compare them to our test circle
@@ -637,14 +636,17 @@ void GLDashingCircleEffect::setData(const GrGLProgramDataManager& pdman,
     }
 }
 
-void GLDashingCircleEffect::GenKey(const GrGeometryProcessor& processor,
+void GLDashingCircleEffect::GenKey(const GrGeometryProcessor& gp,
                                    const GrBatchTracker& bt,
                                    const GrGLCaps&,
                                    GrProcessorKeyBuilder* b) {
     const DashingCircleBatchTracker& local = bt.cast<DashingCircleBatchTracker>();
-    const DashingCircleEffect& dce = processor.cast<DashingCircleEffect>();
-    b->add32(local.fUsesLocalCoords && processor.localMatrix().hasPerspective());
-    b->add32(dce.getEdgeType() << 16 | local.fInputColorType);
+    const DashingCircleEffect& dce = gp.cast<DashingCircleEffect>();
+    uint32_t key = 0;
+    key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 : 0x0;
+    key |= ComputePosKey(gp.viewMatrix()) << 1;
+    key |= dce.getEdgeType() << 8;
+    b->add32(key << 16 | local.fInputColorType);
 }
 
 //////////////////////////////////////////////////////////////////////////////
@@ -822,7 +824,7 @@ class GLDashingLineEffect : public GrGLGeometryProcessor {
 public:
     GLDashingLineEffect(const GrGeometryProcessor&, const GrBatchTracker&);
 
-    void onEmitCode(EmitArgs&) SK_OVERRIDE;
+    void onEmitCode(EmitArgs&, GrGPArgs*) SK_OVERRIDE;
 
     static inline void GenKey(const GrGeometryProcessor&,
                               const GrBatchTracker&,
@@ -850,7 +852,7 @@ GLDashingLineEffect::GLDashingLineEffect(const GrGeometryProcessor&,
     fPrevIntervalLength = SK_ScalarMax;
 }
 
-void GLDashingLineEffect::onEmitCode(EmitArgs& args) {
+void GLDashingLineEffect::onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) {
     const DashingLineEffect& de = args.fGP.cast<DashingLineEffect>();
     const DashingLineBatchTracker& local = args.fBT.cast<DashingLineBatchTracker>();
     GrGLGPBuilder* pb = args.fPB;
@@ -885,11 +887,10 @@ void GLDashingLineEffect::onEmitCode(EmitArgs& args) {
     this->addUniformViewMatrix(pb);
 
     // Setup position
-    vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);",  this->position(), this->uViewM(),
-                           de.inPosition()->fName);
+    SetupPosition(vsBuilder, gpArgs, de.inPosition()->fName, de.viewMatrix(), this->uViewM());
 
     // emit transforms
-    this->emitTransforms(args.fPB,  this->position(), de.inPosition()->fName, de.localMatrix(),
+    this->emitTransforms(args.fPB, gpArgs->fPositionVar, de.inPosition()->fName, de.localMatrix(),
                          args.fTransformsIn, args.fTransformsOut);
 
     // transforms all points so that we can compare them to our test rect
@@ -942,14 +943,17 @@ void GLDashingLineEffect::setData(const GrGLProgramDataManager& pdman,
     }
 }
 
-void GLDashingLineEffect::GenKey(const GrGeometryProcessor& processor,
+void GLDashingLineEffect::GenKey(const GrGeometryProcessor& gp,
                                  const GrBatchTracker& bt,
                                  const GrGLCaps&,
                                  GrProcessorKeyBuilder* b) {
     const DashingLineBatchTracker& local = bt.cast<DashingLineBatchTracker>();
-    const DashingLineEffect& de = processor.cast<DashingLineEffect>();
-    b->add32(local.fUsesLocalCoords && processor.localMatrix().hasPerspective());
-    b->add32(de.getEdgeType() << 16 | local.fInputColorType);
+    const DashingLineEffect& de = gp.cast<DashingLineEffect>();
+    uint32_t key = 0;
+    key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 : 0x0;
+    key |= ComputePosKey(gp.viewMatrix()) << 1;
+    key |= de.getEdgeType() << 8;
+    b->add32(key << 16 | local.fInputColorType);
 }
 
 //////////////////////////////////////////////////////////////////////////////
diff --git a/src/gpu/effects/GrDistanceFieldTextureEffect.cpp b/src/gpu/effects/GrDistanceFieldTextureEffect.cpp
index 00713d6351..f65492e9f0 100755
--- a/src/gpu/effects/GrDistanceFieldTextureEffect.cpp
+++ b/src/gpu/effects/GrDistanceFieldTextureEffect.cpp
@@ -35,7 +35,7 @@ public:
 #endif
         {}
 
-    void onEmitCode(EmitArgs& args) SK_OVERRIDE {
+    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE{
         const GrDistanceFieldTextureEffect& dfTexEffect =
                 args.fGP.cast<GrDistanceFieldTextureEffect>();
         const DistanceFieldBatchTracker& local = args.fBT.cast<DistanceFieldBatchTracker>();
@@ -61,11 +61,11 @@ public:
         this->addUniformViewMatrix(pb);
 
         // Setup position
-        vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);",  this->position(), this->uViewM(),
-                               dfTexEffect.inPosition()->fName);
+        SetupPosition(vsBuilder, gpArgs, dfTexEffect.inPosition()->fName,
+                      dfTexEffect.viewMatrix(), this->uViewM());
 
         // emit transforms
-        this->emitTransforms(args.fPB,  this->position(), dfTexEffect.inPosition()->fName,
+        this->emitTransforms(args.fPB, gpArgs->fPositionVar, dfTexEffect.inPosition()->fName,
                              dfTexEffect.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
         const char* textureSizeUniName = NULL;
@@ -166,16 +166,16 @@ public:
         }
     }
 
-    static inline void GenKey(const GrGeometryProcessor& processor,
+    static inline void GenKey(const GrGeometryProcessor& gp,
                               const GrBatchTracker& bt,
                               const GrGLCaps&,
                               GrProcessorKeyBuilder* b) {
-        const GrDistanceFieldTextureEffect& dfTexEffect =
-                processor.cast<GrDistanceFieldTextureEffect>();
+        const GrDistanceFieldTextureEffect& dfTexEffect = gp.cast<GrDistanceFieldTextureEffect>();
         const DistanceFieldBatchTracker& local = bt.cast<DistanceFieldBatchTracker>();
         uint32_t key = dfTexEffect.getFlags();
         key |= local.fInputColorType << 16;
-        key |= local.fUsesLocalCoords && processor.localMatrix().hasPerspective() ? 0x1 << 24: 0x0;
+        key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 << 24: 0x0;
+        key |= ComputePosKey(gp.viewMatrix()) << 25;
         b->add32(key);
     }
 
@@ -324,7 +324,7 @@ public:
                                           const GrBatchTracker&)
         : fColor(GrColor_ILLEGAL), fTextureSize(SkISize::Make(-1, -1)) {}
 
-    void onEmitCode(EmitArgs& args) SK_OVERRIDE {
+    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE{
         const GrDistanceFieldNoGammaTextureEffect& dfTexEffect =
                 args.fGP.cast<GrDistanceFieldNoGammaTextureEffect>();
 
@@ -353,11 +353,11 @@ public:
         this->addUniformViewMatrix(pb);
 
         // Setup position
-        vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);",  this->position(), this->uViewM(),
-                               dfTexEffect.inPosition()->fName);
+        SetupPosition(vsBuilder, gpArgs, dfTexEffect.inPosition()->fName,
+                      dfTexEffect.viewMatrix(), this->uViewM());
 
         // emit transforms
-        this->emitTransforms(args.fPB,  this->position(), dfTexEffect.inPosition()->fName,
+        this->emitTransforms(args.fPB, gpArgs->fPositionVar, dfTexEffect.inPosition()->fName,
                              dfTexEffect.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
         const char* textureSizeUniName = NULL;
@@ -434,17 +434,18 @@ public:
         }
     }
 
-    static inline void GenKey(const GrGeometryProcessor& proc,
+    static inline void GenKey(const GrGeometryProcessor& gp,
                               const GrBatchTracker& bt,
                               const GrGLCaps&,
                               GrProcessorKeyBuilder* b) {
         const GrDistanceFieldNoGammaTextureEffect& dfTexEffect =
-            proc.cast<GrDistanceFieldNoGammaTextureEffect>();
+            gp.cast<GrDistanceFieldNoGammaTextureEffect>();
 
         const DistanceFieldNoGammaBatchTracker& local = bt.cast<DistanceFieldNoGammaBatchTracker>();
         uint32_t key = dfTexEffect.getFlags();
         key |= local.fInputColorType << 16;
-        key |= local.fUsesLocalCoords && proc.localMatrix().hasPerspective() ? 0x1 << 24: 0x0;
+        key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 << 24: 0x0;
+        key |= ComputePosKey(gp.viewMatrix()) << 25;
         b->add32(key);
     }
 
@@ -568,7 +569,7 @@ public:
     , fTextureSize(SkISize::Make(-1,-1))
     , fTextColor(GrColor_ILLEGAL) {}
 
-    void onEmitCode(EmitArgs& args) SK_OVERRIDE {
+    void onEmitCode(EmitArgs& args, GrGPArgs* gpArgs) SK_OVERRIDE{
         const GrDistanceFieldLCDTextureEffect& dfTexEffect =
                 args.fGP.cast<GrDistanceFieldLCDTextureEffect>();
         const DistanceFieldLCDBatchTracker& local = args.fBT.cast<DistanceFieldLCDBatchTracker>();
@@ -591,11 +592,11 @@ public:
         this->addUniformViewMatrix(pb);
 
         // Setup position
-        vsBuilder->codeAppendf("%s = %s * vec3(%s, 1);",  this->position(), this->uViewM(),
-                               dfTexEffect.inPosition()->fName);
+        SetupPosition(vsBuilder, gpArgs, dfTexEffect.inPosition()->fName,
+                      dfTexEffect.viewMatrix(), this->uViewM());
 
         // emit transforms
-        this->emitTransforms(args.fPB,  this->position(), dfTexEffect.inPosition()->fName,
+        this->emitTransforms(args.fPB, gpArgs->fPositionVar, dfTexEffect.inPosition()->fName,
                              dfTexEffect.localMatrix(), args.fTransformsIn, args.fTransformsOut);
 
         const char* textureSizeUniName = NULL;
@@ -749,17 +750,18 @@ public:
         }
     }
 
-    static inline void GenKey(const GrGeometryProcessor& processor,
+    static inline void GenKey(const GrGeometryProcessor& gp,
                               const GrBatchTracker& bt,
                               const GrGLCaps&,
                               GrProcessorKeyBuilder* b) {
         const GrDistanceFieldLCDTextureEffect& dfTexEffect =
-                processor.cast<GrDistanceFieldLCDTextureEffect>();
+                gp.cast<GrDistanceFieldLCDTextureEffect>();
 
         const DistanceFieldLCDBatchTracker& local = bt.cast<DistanceFieldLCDBatchTracker>();
         uint32_t key = dfTexEffect.getFlags();
         key |= local.fInputColorType << 16;
-        key |= local.fUsesLocalCoords && processor.localMatrix().hasPerspective() ? 0x1 << 24: 0x0;
+        key |= local.fUsesLocalCoords && gp.localMatrix().hasPerspective() ? 0x1 << 24: 0x0;
+        key |= ComputePosKey(gp.viewMatrix()) << 25;
         b->add32(key);
     }
 
diff --git a/src/gpu/gl/GrGLGeometryProcessor.h b/src/gpu/gl/GrGLGeometryProcessor.h
index 3c95830fb2..88b69a6d8f 100644
--- a/src/gpu/gl/GrGLGeometryProcessor.h
+++ b/src/gpu/gl/GrGLGeometryProcessor.h
@@ -127,6 +127,7 @@ private:
 };
 
 class GrGLPathRendering;
+class GrGLVertexBuilder;
 /**
  * If a GL effect needs a GrGLFullShaderBuilder* object to emit vertex code, then it must inherit
  * from this class. Since paths don't have vertices, this class is only meant to be used internally
@@ -143,26 +144,47 @@ public:
                           const SkTArray<const GrCoordTransform*, true>& transforms);
 
 protected:
-    const char* position() const { return "pos3"; }
-
     // Many GrGeometryProcessors do not need explicit local coords
     void emitTransforms(GrGLGPBuilder* gp,
-                        const char* position,
+                        const GrShaderVar& posVar,
                         const SkMatrix& localMatrix,
                         const TransformsIn& tin,
                         TransformsOut* tout) {
-        this->emitTransforms(gp, position, position, localMatrix, tin, tout);
+        this->emitTransforms(gp, posVar, posVar.c_str(), localMatrix, tin, tout);
     }
 
     void emitTransforms(GrGLGPBuilder*,
-                        const char* position,
+                        const GrShaderVar& posVar,
                         const char* localCoords,
                         const SkMatrix& localMatrix,
                         const TransformsIn&,
                         TransformsOut*);
 
+    struct GrGPArgs {
+        // The variable used by a GP to store its position. It can be
+        // either a vec2 or a vec3 depending on the presence of perspective.
+        GrShaderVar fPositionVar;
+    };
+
+    // Create the correct type of position variable given the CTM
+    static void SetupPosition(GrGLVertexBuilder* vsBuilder,
+                              GrGPArgs* gpArgs,
+                              const char* posName,
+                              const SkMatrix& mat,
+                              const char* matName);
+
+    static uint32_t ComputePosKey(const SkMatrix& mat) {
+        if (mat.isIdentity()) {
+            return 0x0;
+        } else if (!mat.hasPerspective()) {
+            return 0x01;
+        } else {
+            return 0x02;
+        }
+    }
+
 private:
-    virtual void onEmitCode(EmitArgs&) = 0;
+    virtual void onEmitCode(EmitArgs&, GrGPArgs*) = 0;
 
     typedef GrGLPrimitiveProcessor INHERITED;
 };
diff --git a/src/gpu/gl/GrGLShaderVar.h b/src/gpu/gl/GrGLShaderVar.h
index 0a7b1deda3..e32683ab4f 100644
--- a/src/gpu/gl/GrGLShaderVar.h
+++ b/src/gpu/gl/GrGLShaderVar.h
@@ -88,7 +88,7 @@ public:
              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
         SkASSERT(kVoid_GrSLType != type);
         SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeIsFloatType(type));
-        INHERITED::set(type, typeModifier, name, precision);
+        INHERITED::set(type, name, typeModifier, precision);
         fOrigin = origin;
         fUseUniformFloatArrays = useUniformFloatArrays;
     }
@@ -104,7 +104,7 @@ public:
              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
         SkASSERT(kVoid_GrSLType != type);
         SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeIsFloatType(type));
-        INHERITED::set(type, typeModifier, name, precision);
+        INHERITED::set(type, name, typeModifier, precision);
         fOrigin = origin;
         fUseUniformFloatArrays = useUniformFloatArrays;
     }
@@ -121,7 +121,7 @@ public:
              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
         SkASSERT(kVoid_GrSLType != type);
         SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeIsFloatType(type));
-        INHERITED::set(type, typeModifier, name, count, precision);
+        INHERITED::set(type, name, typeModifier, precision, count);
         fOrigin = origin;
         fUseUniformFloatArrays = useUniformFloatArrays;
     }
@@ -138,7 +138,7 @@ public:
              bool useUniformFloatArrays = USE_UNIFORM_FLOAT_ARRAYS) {
         SkASSERT(kVoid_GrSLType != type);
         SkASSERT(kDefault_GrSLPrecision == precision || GrSLTypeIsFloatType(type));
-        INHERITED::set(type, typeModifier, name, count, precision);
+        INHERITED::set(type, name, typeModifier, precision, count);
         fOrigin = origin;
         fUseUniformFloatArrays = useUniformFloatArrays;
     }
diff --git a/src/gpu/gl/builders/GrGLVertexShaderBuilder.cpp b/src/gpu/gl/builders/GrGLVertexShaderBuilder.cpp
index d67a476c68..a8d08656bd 100644
--- a/src/gpu/gl/builders/GrGLVertexShaderBuilder.cpp
+++ b/src/gpu/gl/builders/GrGLVertexShaderBuilder.cpp
@@ -34,7 +34,7 @@ void GrGLVertexBuilder::emitAttributes(const GrGeometryProcessor& gp) {
     return;
 }
 
-void GrGLVertexBuilder::transformToNormalizedDeviceSpace(const char* pos3) {
+void GrGLVertexBuilder::transformToNormalizedDeviceSpace(const GrShaderVar& posVar) {
     SkASSERT(!fRtAdjustName);
 
     // setup RT Uniform
@@ -44,9 +44,19 @@ void GrGLVertexBuilder::transformToNormalizedDeviceSpace(const char* pos3) {
                                         fProgramBuilder->rtAdjustment(),
                                         &fRtAdjustName);
 
-    // Transform from Skia's device coords to GL's normalized device coords.
-    this->codeAppendf("gl_Position = vec4(dot(%s.xz, %s.xy), dot(%s.yz, %s.zw), 0, %s.z);",
-                      pos3, fRtAdjustName, pos3, fRtAdjustName, pos3);
+    // Transform from Skia's device coords to GL's normalized device coords. Note that
+    // because we want to "nudge" the device space positions we are converting to 
+    // non-homogeneous NDC.
+    if (kVec3f_GrSLType == posVar.getType()) {
+        this->codeAppendf("gl_Position = vec4(dot(%s.xz, %s.xy)/%s.z, dot(%s.yz, %s.zw)/%s.z, 0, 1);",
+                          posVar.c_str(), fRtAdjustName, posVar.c_str(),
+                          posVar.c_str(), fRtAdjustName, posVar.c_str());
+    } else {
+        SkASSERT(kVec2f_GrSLType == posVar.getType());
+        this->codeAppendf("gl_Position = vec4(%s.x * %s.x + %s.y, %s.y * %s.z + %s.w, 0, 1);",
+                          posVar.c_str(), fRtAdjustName, fRtAdjustName,
+                          posVar.c_str(), fRtAdjustName, fRtAdjustName);
+    }
 
     // We could have the GrGeometryProcessor do this, but its just easier to have it performed here.
     // If we ever need to set variable pointsize, then we can reinvestigate
diff --git a/src/gpu/gl/builders/GrGLVertexShaderBuilder.h b/src/gpu/gl/builders/GrGLVertexShaderBuilder.h
index 355f37e361..4c99a7b728 100644
--- a/src/gpu/gl/builders/GrGLVertexShaderBuilder.h
+++ b/src/gpu/gl/builders/GrGLVertexShaderBuilder.h
@@ -16,7 +16,7 @@ class GrGLVertexBuilder : public GrGLShaderBuilder {
 public:
     GrGLVertexBuilder(GrGLProgramBuilder* program);
 
-    void transformToNormalizedDeviceSpace(const char* pos3);
+    void transformToNormalizedDeviceSpace(const GrShaderVar& posVar);
     void emitAttributes(const GrGeometryProcessor& gp);
 
     void addAttribute(const GrGeometryProcessor::Attribute* attr) {