First step to moving vertex attributes to the geometryProcessor

src/gpu/gl/builders/GrGLProgramBuilder.h

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLProgramBuilder_DEFINED
 #define GrGLProgramBuilder_DEFINED
 
@@ skipping 108 matching lines @@
 };
 
 struct GrGLGeoToFrag : public GrGLVarying {
     GrGLGeoToFrag(GrSLType type)
         : GrGLVarying(type, kGeoToFrag_Varying) {}
 };
 
 /* a specialization of the above for GPs.  Lets the user add uniforms, varyings, and VS / FS code */
 class GrGLGPBuilder : public virtual GrGLUniformBuilder {
 public:
+    /*
+     * addVarying allows fine grained control for setting up varyings between stages.  If you just
+     * need to take an attribute and pass it through to an output value in a fragment shader, use
+     * addPassThroughAttribute.
+     * TODO convert most uses of addVarying to addPassThroughAttribute
+     */
     virtual void addVarying(const char* name,
                             GrGLVarying*,
                             GrGLShaderVar::Precision fsPrecision=GrGLShaderVar::kDefault_Precision) = 0;
 
+    /*
+     * This call can be used by GP to pass an attribute through all shaders directly to 'output' in
+     * the fragment shader.  Though this call effects both the vertex shader and fragment shader,
+     * it expects 'output' to be defined in the fragment shader before this call is made.
+     * TODO it might be nicer behavior to have a flag to declare output inside this call
+     */
+    virtual void addPassThroughAttribute(const GrGeometryProcessor::GrAttribute*,
+                                         const char* output) = 0;
+
     // TODO rename getFragmentBuilder
     virtual GrGLGPFragmentBuilder* getFragmentShaderBuilder() = 0;
     virtual GrGLVertexBuilder* getVertexShaderBuilder() = 0;
 
     /*
      * *NOTE* NO MEMBERS ALLOWED, MULTIPLE INHERITANCE
      */
 };
 
 /* a specializations for FPs. Lets the user add uniforms and FS code */
@@ skipping 55 matching lines @@
     virtual GrGpuGL* gpu() const SK_OVERRIDE { return fGpu; }
 
     virtual GrGLFPFragmentBuilder* getFragmentShaderBuilder() SK_OVERRIDE { return &fFS; }
     virtual GrGLVertexBuilder* getVertexShaderBuilder() SK_OVERRIDE { return &fVS; }
 
     virtual void addVarying(
             const char* name,
             GrGLVarying*,
             GrGLShaderVar::Precision fsPrecision=GrGLShaderVar::kDefault_Precision) SK_OVERRIDE;
 
+    virtual void addPassThroughAttribute(const GrGeometryProcessor::GrAttribute*,
+                                         const char* output) SK_OVERRIDE;
+
+
     // Handles for program uniforms (other than per-effect uniforms)
     struct BuiltinUniformHandles {
         UniformHandle       fViewMatrixUni;
         UniformHandle       fRTAdjustmentUni;
         UniformHandle       fColorUni;
         UniformHandle       fCoverageUni;
 
         // We use the render target height to provide a y-down frag coord when specifying
         // origin_upper_left is not supported.
         UniformHandle       fRTHeightUni;
@@ skipping 17 matching lines @@
 
     const GrOptDrawState& optState() const { return fOptState; }
     const GrProgramDesc& desc() const { return fDesc; }
     const GrProgramDesc::KeyHeader& header() const { return fDesc.header(); }
 
     // Generates a name for a variable. The generated string will be name prefixed by the prefix
     // char (unless the prefix is '\0'). It also mangles the name to be stage-specific if we're
     // generating stage code.
     void nameVariable(SkString* out, char prefix, const char* name);
     void setupUniformColorAndCoverageIfNeeded(GrGLSLExpr4* inputColor, GrGLSLExpr1* inputCoverage);
+    // Generates a possibly mangled name for a stage variable and writes it to the fragment shader.
+    // If GrGLSLExpr4 has a valid name then it will use that instead
+    void nameExpression(GrGLSLExpr4*, const char* baseName);
     void emitAndInstallProcs(GrGLSLExpr4* inputColor,
                              GrGLSLExpr4* inputCoverage);
     void emitAndInstallFragProcs(int procOffset, int numProcs, GrGLSLExpr4* inOut);
-    template <class Proc>
-    void emitAndInstallProc(const Proc&,
+    void emitAndInstallProc(const GrPendingFragmentStage&,
                             int index,
                             const GrGLSLExpr4& input,
                             GrGLSLExpr4* output);
 
+    void emitAndInstallProc(const GrGeometryProcessor&,
+                            GrGLSLExpr4* outputColor,
+                            GrGLSLExpr4* outputCoverage);
+
     // these emit functions help to keep the createAndEmitProcessors template general
     void emitAndInstallProc(const GrPendingFragmentStage&,
                             const char* outColor,
                             const char* inColor);
     void emitAndInstallProc(const GrGeometryProcessor&,
-                            const char* outCoverage,
-                            const char* inCoverage);
+                            const char* outColor,
+                            const char* outCoverage);
+
     void verify(const GrGeometryProcessor&);
     void verify(const GrFragmentProcessor&);
     void emitSamplers(const GrProcessor&,
                       GrGLProcessor::TextureSamplerArray* outSamplers,
                       GrGLInstalledProc*);
 
     // each specific program builder has a distinct transform and must override this function
     virtual void emitTransforms(const GrPendingFragmentStage&,
                                 GrGLProcessor::TransformedCoordsArray* outCoords,
                                 GrGLInstalledFragProc*);
@@ skipping 94 matching lines @@
          int            fTextureUnit;
      };
      SkSTArray<4, Sampler, true> fSamplers;
 };
 
 struct GrGLInstalledGeoProc : public GrGLInstalledProc {
     SkAutoTDelete<GrGLGeometryProcessor> fGLProc;
 };
 
 struct GrGLInstalledFragProc : public GrGLInstalledProc {
-    GrGLInstalledFragProc(bool useLocalCoords) : fGLProc(NULL), fLocalCoordAttrib(useLocalCoords) {}
+    GrGLInstalledFragProc() : fGLProc(NULL) {}
     class ShaderVarHandle {
     public:
         bool isValid() const { return fHandle > -1; }
         ShaderVarHandle() : fHandle(-1) {}
         ShaderVarHandle(int value) : fHandle(value) { SkASSERT(this->isValid()); }
         int handle() const { SkASSERT(this->isValid()); return fHandle; }
         UniformHandle convertToUniformHandle() {
             SkASSERT(this->isValid());
             return GrGLProgramDataManager::UniformHandle::CreateFromUniformIndex(fHandle);
         }
 
     private:
         int fHandle;
     };
 
     struct Transform {
         Transform() : fType(kVoid_GrSLType) { fCurrentValue = SkMatrix::InvalidMatrix(); }
         ShaderVarHandle fHandle;
         SkMatrix       fCurrentValue;
         GrSLType       fType;
     };
 
     SkAutoTDelete<GrGLFragmentProcessor> fGLProc;
     SkSTArray<2, Transform, true>        fTransforms;
-    bool                                 fLocalCoordAttrib;
 };
 
 struct GrGLInstalledFragProcs : public SkRefCnt {
     virtual ~GrGLInstalledFragProcs();
     SkSTArray<8, GrGLInstalledFragProc*, true> fProcs;
 };
 
 #endif