| /* |
| * 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 GrGLFragmentShaderBuilder_DEFINED |
| #define GrGLFragmentShaderBuilder_DEFINED |
| |
| #include "GrGLShaderBuilder.h" |
| |
| class GrGLVarying; |
| |
| /* |
| * This base class encapsulates the functionality which the GP uses to build fragment shaders |
| */ |
| class GrGLFragmentBuilder : public GrGLShaderBuilder { |
| public: |
| GrGLFragmentBuilder(GrGLProgramBuilder* program) : INHERITED(program) {} |
| virtual ~GrGLFragmentBuilder() {} |
| /** |
| * 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. |
| */ |
| virtual bool enableFeature(GLSLFeature) = 0; |
| |
| /** |
| * This returns a variable name to access the 2D, perspective correct version of the coords in |
| * the fragment shader. If the coordinates at index are 3-dimensional, it immediately emits a |
| * perspective divide into the fragment shader (xy / z) to convert them to 2D. |
| */ |
| virtual SkString ensureFSCoords2D(const GrGLProcessor::TransformedCoordsArray& coords, |
| int index) = 0; |
| |
| |
| /** 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). */ |
| virtual const char* fragmentPosition() = 0; |
| |
| private: |
| friend class GrGLPathProcessor; |
| |
| typedef GrGLShaderBuilder INHERITED; |
| }; |
| |
| /* |
| * Fragment processor's, in addition to all of the above, may need to use dst color so they use |
| * this builder to create their shader. Because this is the only shader builder the FP sees, we |
| * just call it FPShaderBuilder |
| */ |
| class GrGLXPFragmentBuilder : public GrGLFragmentBuilder { |
| public: |
| GrGLXPFragmentBuilder(GrGLProgramBuilder* program) : INHERITED(program) {} |
| |
| /** Returns the variable name that holds the color of the destination pixel. This may be NULL if |
| no effect advertised that it will read the destination. */ |
| virtual const char* dstColor() = 0; |
| |
| /** Adds any necessary layout qualifiers in order to legalize the supplied blend equation with |
| this shader. It is only legal to call this method with an advanced blend equation, and only |
| if these equations are supported. */ |
| virtual void enableAdvancedBlendEquationIfNeeded(GrBlendEquation) = 0; |
| |
| private: |
| typedef GrGLFragmentBuilder INHERITED; |
| }; |
| |
| // TODO rename to Fragment Builder |
| class GrGLFragmentShaderBuilder : public GrGLXPFragmentBuilder { |
| public: |
| typedef uint8_t DstReadKey; |
| typedef uint8_t FragPosKey; |
| |
| /** Returns a key for adding code to read the dst texture color in service of effects that |
| require reading the dst. It must not return 0 because 0 indicates that there is no dst |
| texture at all (in which case this function should not be called). */ |
| static DstReadKey KeyForDstRead(const GrTexture* dsttexture, const GrGLCaps&); |
| |
| /** Returns a key for reading the fragment location. This should only be called if there is an |
| effect that will requires the fragment position. If the fragment position is not required, |
| the key is 0. */ |
| static FragPosKey KeyForFragmentPosition(const GrRenderTarget* dst, const GrGLCaps&); |
| |
| GrGLFragmentShaderBuilder(GrGLProgramBuilder* program, uint8_t fragPosKey); |
| |
| // true public interface, defined explicitly in the abstract interfaces above |
| bool enableFeature(GLSLFeature) override; |
| virtual SkString ensureFSCoords2D(const GrGLProcessor::TransformedCoordsArray& coords, |
| int index) override; |
| const char* fragmentPosition() override; |
| const char* dstColor() override; |
| |
| void enableAdvancedBlendEquationIfNeeded(GrBlendEquation) override; |
| |
| private: |
| // Private public interface, used by GrGLProgramBuilder to build a fragment shader |
| void enableCustomOutput(); |
| void enableSecondaryOutput(); |
| const char* getPrimaryColorOutputName() const; |
| const char* getSecondaryColorOutputName() const; |
| bool compileAndAttachShaders(GrGLuint programId, SkTDArray<GrGLuint>* shaderIds); |
| void bindFragmentShaderLocations(GrGLuint programID); |
| |
| // As GLProcessors emit code, there are some conditions we need to verify. We use the below |
| // state to track this. The reset call is called per processor emitted. |
| bool hasReadDstColor() const { return fHasReadDstColor; } |
| bool hasReadFragmentPosition() const { return fHasReadFragmentPosition; } |
| void reset() { |
| fHasReadDstColor = false; |
| fHasReadFragmentPosition = false; |
| } |
| |
| /* |
| * An internal call for GrGLProgramBuilder to use to add varyings to the vertex shader |
| */ |
| void addVarying(GrGLVarying*, GrSLPrecision); |
| |
| /** |
| * Features that should only be enabled by GrGLFragmentShaderBuilder itself. |
| */ |
| enum GLSLPrivateFeature { |
| kFragCoordConventions_GLSLPrivateFeature = kLastGLSLFeature + 1, |
| kBlendEquationAdvanced_GLSLPrivateFeature, |
| kLastGLSLPrivateFeature = kBlendEquationAdvanced_GLSLPrivateFeature |
| }; |
| |
| // Interpretation of DstReadKey when generating code |
| enum { |
| kNoDstRead_DstReadKey = 0, |
| kYesDstRead_DstReadKeyBit = 0x1, // Set if we do a dst-copy-read. |
| kUseAlphaConfig_DstReadKeyBit = 0x2, // Set if dst-copy config is alpha only. |
| kTopLeftOrigin_DstReadKeyBit = 0x4, // Set if dst-copy origin is top-left. |
| }; |
| |
| // Interpretation of FragPosKey when generating code |
| enum { |
| 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. |
| }; |
| |
| static const char* kDstTextureColorName; |
| |
| bool fHasCustomColorOutput; |
| bool fHasSecondaryOutput; |
| bool fSetupFragPosition; |
| bool fTopLeftFragPosRead; |
| int fCustomColorOutputIndex; |
| |
| // some state to verify shaders and effects are consistent, this is reset between effects by |
| // the program creator |
| bool fHasReadDstColor; |
| bool fHasReadFragmentPosition; |
| |
| friend class GrGLProgramBuilder; |
| |
| typedef GrGLXPFragmentBuilder INHERITED; |
| }; |
| |
| #endif |