Initial refactor of shaderbuilder

src/gpu/gl/builders/GrGLShaderBuilder.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 GrGLShaderBuilder_DEFINED
+#define GrGLShaderBuilder_DEFINED
+
+#include "gl/GrGLProgramDesc.h"
+#include "gl/GrGLProgramEffects.h"
+#include "gl/GrGLSL.h"
+#include "gl/GrGLProgramDataManager.h"
+#include "GrAllocator.h"
+#include "GrBackendEffectFactory.h"
+#include "GrColor.h"
+#include "GrEffect.h"
+#include "SkTypes.h"
+
+#include <stdarg.h>
+
+class GrGLContextInfo;
+class GrEffectStage;
+class GrGLProgramDesc;
+class GrGLProgramBuilder;
+class GrGLFullProgramBuilder;
+
+/**
+  base class for all shaders

[bsalomon, 2014/08/21 17:18:00]

How about "... all shader builders"?

+*/
+class GrGLShaderBuilder {
+public:
+    typedef GrGLProgramEffects::TransformedCoordsArray TransformedCoordsArray;
+    typedef GrGLProgramEffects::TextureSampler TextureSampler;
+    GrGLShaderBuilder(GrGLProgramBuilder* program);
+
+    void addInput(GrGLShaderVar i) { fInputs.push_back(i); }
+    void addOutput(GrGLShaderVar i) { fOutputs.push_back(i); }
+
+    /*
+     * We put texture lookups in the base class because it is TECHNICALLY possible to do texture
+     * lookups in any kind of shader.  However, For the most part, usage of these features should be

[bsalomon, 2014/08/21 17:18:00]

Would it work anywhere else? Maybe we should say "currently use of textures is
only supported in fragment shaders"?

If it does just work from other shaders, then great.

+     * confined to the fragment shader.
+     */
+    /** 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;
+
+    /** Version of above that appends the result to the fragment shader code instead.*/
+    void appendTextureLookup(const TextureSampler&,
+                             const char* coordName,
+                             GrSLType coordType = kVec2f_GrSLType);
+
+
+    /** Does the work of appendTextureLookup and modulates the result by modulation. The result is
+        always a vec4. modulation and the swizzle specified by TextureSampler must both be vec4 or
+        float. If modulation is "" or NULL it this function acts as though appendTextureLookup were
+        called. */
+    void appendTextureLookupAndModulate(const char* modulation,
+                                        const TextureSampler&,
+                                        const char* coordName,
+                                        GrSLType coordType = kVec2f_GrSLType);
+
+    /** If texture swizzling is available using tex parameters then it is preferred over mangling
+        the generated shader code. This potentially allows greater reuse of cached shaders. */
+    static const GrGLenum* GetTexParamSwizzle(GrPixelConfig config, const GrGLCaps& caps);
+
+    /**
+    * Called by GrGLEffects to add code to one of the shaders.
+    */
+    void codeAppendf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
+       va_list args;
+       va_start(args, format);
+       fCode.appendVAList(format, args);
+       va_end(args);
+    }
+
+    void codeAppend(const char* str) { fCode.append(str); }
+
+    void codePrependf(const char format[], ...) SK_PRINTF_LIKE(2, 3) {
+       va_list args;
+       va_start(args, format);
+       fCode.prependVAList(format, args);
+       va_end(args);
+    }
+
+    /** Emits a helper function outside of main() in the fragment shader. */
+    void emitFunction(GrSLType returnType,
+                      const char* name,
+                      int argCnt,
+                      const GrGLShaderVar* args,
+                      const char* body,
+                      SkString* outName);
+
+    /*
+     * Get parent builder for adding uniforms
+     */
+    GrGLProgramBuilder* getProgramBuilder() { return fProgram; }
+
+    /**
+     * Helper for begining and ending a block in the fragment code.
+     */
+    class ShaderBlock {
+    public:
+        ShaderBlock(GrGLShaderBuilder* builder) : fBuilder(builder) {
+            SkASSERT(NULL != builder);
+            fBuilder->codeAppend("{");
+        }
+
+        ~ShaderBlock() {
+            fBuilder->codeAppend("}");
+        }
+    private:
+        GrGLShaderBuilder* fBuilder;
+    };
+protected:
+
+    /*
+     * this super low level function is just for use internally to builders
+     */
+    void appendTextureLookup(const char* samplerName,
+                             const char* coordName,
+                             uint32_t configComponentMask,
+                             const char* swizzle);
+
+    /*
+     * A general function which enables an extension in a shader if the feature bit is not present
+     */
+    void addFeature(uint32_t featureBit, const char* extensionName);
+
+    typedef GrTAllocator<GrGLShaderVar> VarArray;
+
+    GrGLProgramBuilder* fProgram;
+
+    SkString fCode;
+    SkString fFunctions;
+    SkString fExtensions;
+
+    VarArray fInputs;
+    VarArray fOutputs;
+    uint32_t fFeaturesAddedMask;
+};
+
+class GrGLFullShaderBuilder : public GrGLShaderBuilder {

[bsalomon, 2014/08/21 17:18:00]

Why do we need this subclass?

+public:
+    GrGLFullShaderBuilder(GrGLFullProgramBuilder* program);
+
+    GrGLFullProgramBuilder* fullProgram() { return fFullProgram; }
+protected:
+    GrGLFullProgramBuilder* fFullProgram;
+private:
+    typedef GrGLShaderBuilder INHERITED;
+};
+#endif