Isolate VertexBuilder from GrGLShaderBuilder

src/gpu/gl/GrGLShaderBuilder.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef GrGLShaderBuilder_DEFINED
 #define GrGLShaderBuilder_DEFINED
 
@@ skipping 78 matching lines @@
         }
 
         uint32_t                          fConfigComponentMask;
         char                              fSwizzle[5];
         GrGLUniformManager::UniformHandle fSamplerUniform;
 
         friend class GrGLShaderBuilder; // to call init().
     };
 
     typedef SkTArray<TextureSampler> TextureSamplerArray;
+    typedef GrTAllocator<GrGLShaderVar> VarArray;
 
     enum ShaderVisibility {
         kVertex_Visibility   = 0x1,
         kGeometry_Visibility = 0x2,
         kFragment_Visibility = 0x4,
     };
 
-    GrGLShaderBuilder(const GrGLContextInfo&, GrGLUniformManager&, const GrGLProgramDesc&);
+    GrGLShaderBuilder(const GrGLContextInfo&,
+                      GrGLUniformManager&,
+                      const GrGLProgramDesc&,
+                      bool needsVertexShader);
 
     /**
      * Use of these features may require a GLSL extension to be enabled. Shaders may not compile
      * if code is added that uses one of these features without calling enableFeature()
      */
     enum GLSLFeature {
         kStandardDerivatives_GLSLFeature = 0,
 
         kLastGLSLFeature = kStandardDerivatives_GLSLFeature
     };
 
     /**
      * If the feature is supported then true is returned and any necessary #extension declarations
      * are added to the shaders. If the feature is not supported then false will be returned.
      */
     bool enableFeature(GLSLFeature);
 
     /**
-     * Called by GrGLEffects to add code to one of the shaders.
+     * Called by GrGLEffects to add code the fragment shader.
      */
-    void vsCodeAppendf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
-        va_list args;
-        va_start(args, format);
-        fVSCode.appendf(format, args);
-        va_end(args);
-    }
-
-    void gsCodeAppendf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
-        va_list args;
-        va_start(args, format);
-        fGSCode.appendf(format, args);
-        va_end(args);
-    }
-
     void fsCodeAppendf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
         va_list args;
         va_start(args, format);
         fFSCode.appendf(format, args);
         va_end(args);
     }
 
-    void vsCodeAppend(const char* str) { fVSCode.append(str); }
-    void gsCodeAppend(const char* str) { fGSCode.append(str); }
     void fsCodeAppend(const char* str) { fFSCode.append(str); }
 
     /** Appends a 2D texture sample with projection if necessary. coordType must either be Vec2f or
         Vec3f. The latter is interpreted as projective texture coords. The vec length and swizzle
         order of the result depends on the GrTextureAccess associated with the TextureSampler. */
     void appendTextureLookup(SkString* out,
                              const TextureSampler&,
                              const char* coordName,
                              GrSLType coordType = kVec2f_GrSLType) const;
 
@@ skipping 13 matching lines @@
                                           GrSLType coordType = kVec2f_GrSLType);
 
     /** Emits a helper function outside of main() in the fragment shader. */
     void fsEmitFunction(GrSLType returnType,
                         const char* name,
                         int argCnt,
                         const GrGLShaderVar* args,
                         const char* body,
                         SkString* outName);
 
+    /** Add input/output variable declarations (i.e. 'varying') to the fragment shader. */
+    GrGLShaderVar& fsInputAppend() { return fFSInputs.push_back(); }
+    GrGLShaderVar& fsOutputAppend() { return fFSOutputs.push_back(); }
+    GrGLShaderVar& fsInputAppend(const GrGLShaderVar& var) { return fFSInputs.push_back(var); }
+    GrGLShaderVar& fsOutputAppend(const GrGLShaderVar& var) { return fFSOutputs.push_back(var); }
+
     /** Generates a EffectKey for the shader code based on the texture access parameters and the
         capabilities of the GL context.  This is useful for keying the shader programs that may
         have multiple representations, based on the type/format of textures used. */
     static GrBackendEffectFactory::EffectKey KeyForTextureAccess(const GrTextureAccess&,
                                                                  const GrGLCaps&);
 
     typedef uint8_t DstReadKey;
     typedef uint8_t FragPosKey;
 
     /**  Returns a key for adding code to read the copy-of-dst color in service of effects that
@@ skipping 33 matching lines @@
         return fUniformManager.getBuilderUniform(fUniforms, u).fVariable;
     }
 
     /**
      * Shortcut for getUniformVariable(u).c_str()
      */
     const char* getUniformCStr(GrGLUniformManager::UniformHandle u) const {
         return this->getUniformVariable(u).c_str();
     }
 
-   /** Add a vertex attribute to the current program that is passed in from the vertex data.
-       Returns false if the attribute was already there, true otherwise. */
-    bool addAttribute(GrSLType type, const char* name);
-
-   /** Add a varying variable to the current program to pass values between vertex and fragment
-        shaders. If the last two parameters are non-NULL, they are filled in with the name
-        generated. */
-    void addVarying(GrSLType type,
-                    const char* name,
-                    const char** vsOutName = NULL,
-                    const char** fsInName = NULL);
-
     /** Returns a variable name that represents the position of the fragment in the FS. The position
         is in device space (e.g. 0,0 is the top left and pixel centers are at half-integers). */
     const char* fragmentPosition();
 
-    /** Returns a vertex attribute that represents the vertex position in the VS. This is the
-        pre-matrix position and is commonly used by effects to compute texture coords via a matrix.
-      */
-    const GrGLShaderVar& positionAttribute() const { return *fPositionVar; }
-
-    /** Returns a vertex attribute that represents the local coords in the VS. This may be the same
-        as positionAttribute() or it may not be. It depends upon whether the rendering code
-        specified explicit local coords or not in the GrDrawState. */
-    const GrGLShaderVar& localCoordsAttribute() const { return *fLocalCoordsVar; }
-
     /** Returns the color of the destination pixel. This may be NULL if no effect advertised
         that it will read the destination. */
     const char* dstColor();
 
     /**
-     * Are explicit local coordinates provided as input to the vertex shader.
-     */
-    bool hasExplicitLocalCoords() const { return (fLocalCoordsVar != fPositionVar); }
-
-    /**
      * Interfaces used by GrGLProgram.
      * TODO: Hide these from the GrEffects using friend or splitting this into two related classes.
      * Also, GrGLProgram's shader string construction should be moved to this class.
      */
 
-    /** Called after building is complete to get the final shader string. */
-    void vsGetShader(SkString*) const;
-    void gsGetShader(SkString*) const;
+    /** Called after building is complete to get the final shader string. To acces the vertex
+        and geometry shaders, use the VertexBuilder. */
     void fsGetShader(SkString*) const;
 
     /**
      * Adds code for effects. effectStages contains the effects to add. effectKeys[i] is the key
      * generated from effectStages[i]. An entry in effectStages can be NULL, in which case it is
      * skipped. Moreover, if the corresponding key is GrGLEffect::NoEffectKey then it is skipped.
      * inOutFSColor specifies the input color to the first stage and is updated to be the
      * output color of the last stage. fsInOutColorKnownValue specifies whether the input color
      * has a known constant value and is updated to refer to the status of the output color.
      * The handles to texture samplers for effectStage[i] are added to effectSamplerHandles[i]. The
@@ skipping 12 matching lines @@
     GrGLUniformManager::UniformHandle getDstCopyTopLeftUniform() const {
         return fDstCopyTopLeftUniform;
     }
     GrGLUniformManager::UniformHandle getDstCopyScaleUniform() const {
         return fDstCopyScaleUniform;
     }
     GrGLUniformManager::UniformHandle getDstCopySamplerUniform() const {
         return fDstCopySampler.fSamplerUniform;
     }
 
-    struct AttributePair {
-        void set(int index, const SkString& name) {
-            fIndex = index; fName = name;
+    /** Helper class used to build the vertex and geometry shaders. This functionality
+        is kept separate from the rest of GrGLShaderBuilder to allow for shaders programs
+        that only use the fragment shader. */
+    class VertexBuilder {
+    public:
+        VertexBuilder(GrGLShaderBuilder* parent, const GrGLProgramDesc&);
+
+        /**
+         * Called by GrGLEffects to add code to one of the shaders.
+         */
+        void vsCodeAppendf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
+            va_list args;
+            va_start(args, format);
+            fVSCode.appendf(format, args);
+            va_end(args);
         }
-        int      fIndex;
-        SkString fName;
+
+        void gsCodeAppendf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
+            va_list args;
+            va_start(args, format);
+            fGSCode.appendf(format, args);
+            va_end(args);
+        }
+
+        void vsCodeAppend(const char* str) { fVSCode.append(str); }
+        void gsCodeAppend(const char* str) { fGSCode.append(str); }
+
+       /** Add a vertex attribute to the current program that is passed in from the vertex data.
+           Returns false if the attribute was already there, true otherwise. */
+        bool addAttribute(GrSLType type, const char* name);
+
+       /** Add a varying variable to the current program to pass values between vertex and fragment
+            shaders. If the last two parameters are non-NULL, they are filled in with the name
+            generated. */
+        void addVarying(GrSLType type,
+                        const char* name,
+                        const char** vsOutName = NULL,
+                        const char** fsInName = NULL);
+
+        /** Returns a vertex attribute that represents the vertex position in the VS. This is the
+            pre-matrix position and is commonly used by effects to compute texture coords via a matrix.
+          */
+        const GrGLShaderVar& positionAttribute() const { return *fPositionVar; }
+
+        /** Returns a vertex attribute that represents the local coords in the VS. This may be the same
+            as positionAttribute() or it may not be. It depends upon whether the rendering code
+            specified explicit local coords or not in the GrDrawState. */
+        const GrGLShaderVar& localCoordsAttribute() const { return *fLocalCoordsVar; }
+
+        /**
+         * Are explicit local coordinates provided as input to the vertex shader.
+         */
+        bool hasExplicitLocalCoords() const { return (fLocalCoordsVar != fPositionVar); }
+
+        /** Called after building is complete to get the final shader string. */
+        void vsGetShader(SkString*) const;
+        void gsGetShader(SkString*) const;
+
+        struct AttributePair {
+            void set(int index, const SkString& name) {
+                fIndex = index; fName = name;
+            }
+            int      fIndex;
+            SkString fName;
+        };
+        const SkTArray<AttributePair, true>& getEffectAttributes() const {
+            return fEffectAttributes;
+        }
+        bool addEffectAttribute(int attributeIndex, GrSLType type, const SkString& name);
+        const SkString* getEffectAttributeName(int attributeIndex) const;
+
+        // TODO: Everything below here private.
+    public:
+
+        VarArray    fVSAttrs;
+        VarArray    fVSOutputs;
+        VarArray    fGSInputs;
+        VarArray    fGSOutputs;
+        SkString    fGSHeader; // layout qualifiers specific to GS
+
+    private:
+        GrGLShaderBuilder*                  fParent;
+
+        bool                                fUsesGS;
+
+        SkString                            fVSCode;
+        SkString                            fGSCode;
+
+        SkSTArray<10, AttributePair, true>  fEffectAttributes;
+
+        GrGLShaderVar*                      fPositionVar;
+        GrGLShaderVar*                      fLocalCoordsVar;
     };
-    const SkTArray<AttributePair, true>& getEffectAttributes() const {
-        return fEffectAttributes;
-    }
-    const SkString* getEffectAttributeName(int attributeIndex) const;
+
+    /** Gets the vertex builder that is used to construct the vertex and geometry shaders.
+        It may be NULL if this shader program is only meant to have a fragment shader. */
+    VertexBuilder* getVertexBuilder() const { return fVertexBuilder.get(); }
 
     // TODO: Make this do all the compiling, linking, etc.
     void finished(GrGLuint programID);
 
     const GrGLContextInfo& ctxInfo() const { return fCtxInfo; }
 
 private:
-    typedef GrTAllocator<GrGLShaderVar> VarArray;
-
     void appendDecls(const VarArray&, SkString*) const;
     void appendUniformDecls(ShaderVisibility, SkString*) const;
 
     typedef GrGLUniformManager::BuilderUniform BuilderUniform;
     GrGLUniformManager::BuilderUniformArray fUniforms;
 
-    // TODO: Everything below here private.
-public:
-
-    VarArray    fVSAttrs;
-    VarArray    fVSOutputs;
-    VarArray    fGSInputs;
-    VarArray    fGSOutputs;
-    VarArray    fFSInputs;
-    SkString    fGSHeader; // layout qualifiers specific to GS
-    VarArray    fFSOutputs;
-
 private:
     class CodeStage : GrNoncopyable {
     public:
         CodeStage() : fNextIndex(0), fCurrentIndex(-1), fEffectStage(NULL) {}
 
         bool inStageCode() const {
             this->validate();
             return NULL != fEffectStage;
         }
 
@@ skipping 70 matching lines @@
         kNoFragPosRead_FragPosKey           = 0,  // The fragment positition will not be needed.
         kTopLeftFragPosRead_FragPosKey      = 0x1,// Read frag pos relative to top-left.
         kBottomLeftFragPosRead_FragPosKey   = 0x2,// Read frag pos relative to bottom-left.
     };
 
     const GrGLContextInfo&              fCtxInfo;
     GrGLUniformManager&                 fUniformManager;
     uint32_t                            fFSFeaturesAddedMask;
     SkString                            fFSFunctions;
     SkString                            fFSExtensions;
-
-    bool                                fUsesGS;
+    VarArray                            fFSInputs;
+    VarArray                            fFSOutputs;
 
     SkString                            fFSCode;
-    SkString                            fVSCode;
-    SkString                            fGSCode;
 
     bool                                fSetupFragPosition;
     TextureSampler                      fDstCopySampler;
 
     GrGLUniformManager::UniformHandle   fRTHeightUniform;
     GrGLUniformManager::UniformHandle   fDstCopyTopLeftUniform;
     GrGLUniformManager::UniformHandle   fDstCopyScaleUniform;
 
     bool                                fTopLeftFragPosRead;
 
-    SkSTArray<10, AttributePair, true>  fEffectAttributes;
-
-    GrGLShaderVar*                      fPositionVar;
-    GrGLShaderVar*                      fLocalCoordsVar;
-
+    SkAutoTDelete<VertexBuilder> fVertexBuilder;
 };
 
 #endif