| /* |
| * 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 GrGLSLFragmentShaderBuilder_DEFINED |
| #define GrGLSLFragmentShaderBuilder_DEFINED |
| |
| #include "GrGLSLShaderBuilder.h" |
| |
| #include "glsl/GrGLSLProcessorTypes.h" |
| |
| class GrRenderTarget; |
| class GrGLSLVarying; |
| |
| /* |
| * This base class encapsulates the functionality which the GP uses to build fragment shaders |
| */ |
| class GrGLSLFragmentBuilder : public GrGLSLShaderBuilder { |
| public: |
| GrGLSLFragmentBuilder(GrGLSLProgramBuilder* program) |
| : INHERITED(program) |
| , fHasCustomColorOutput(false) |
| , fHasSecondaryOutput(false) { |
| fSubstageIndices.push_back(0); |
| } |
| virtual ~GrGLSLFragmentBuilder() {} |
| /** |
| * 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, |
| kPixelLocalStorage_GLSLFeature = 1, |
| kLastGLSLFeature = kPixelLocalStorage_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 GrGLSLTransformedCoordsArray& 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; |
| |
| /** |
| * Fragment procs with child procs should call these functions before/after calling emitCode |
| * on a child proc. |
| */ |
| void onBeforeChildProcEmitCode(); |
| void onAfterChildProcEmitCode(); |
| |
| const SkString& getMangleString() const { return fMangleString; } |
| |
| bool hasCustomColorOutput() const { return fHasCustomColorOutput; } |
| bool hasSecondaryOutput() const { return fHasSecondaryOutput; } |
| |
| void declAppendf(const char* fmt, ...); |
| |
| protected: |
| bool fHasCustomColorOutput; |
| bool fHasSecondaryOutput; |
| |
| private: |
| /* |
| * State that tracks which child proc in the proc tree is currently emitting code. This is |
| * used to update the fMangleString, which is used to mangle the names of uniforms and functions |
| * emitted by the proc. fSubstageIndices is a stack: its count indicates how many levels deep |
| * we are in the tree, and its second-to-last value is the index of the child proc at that |
| * level which is currently emitting code. For example, if fSubstageIndices = [3, 1, 2, 0], that |
| * means we're currently emitting code for the base proc's 3rd child's 1st child's 2nd child. |
| */ |
| SkTArray<int> fSubstageIndices; |
| |
| /* |
| * The mangle string is used to mangle the names of uniforms/functions emitted by the child |
| * procs so no duplicate uniforms/functions appear in the generated shader program. The mangle |
| * string is simply based on fSubstageIndices. For example, if fSubstageIndices = [3, 1, 2, 0], |
| * then the manglestring will be "_c3_c1_c2", and any uniform/function emitted by that proc will |
| * have "_c3_c1_c2" appended to its name, which can be interpreted as "base proc's 3rd child's |
| * 1st child's 2nd child". |
| */ |
| SkString fMangleString; |
| |
| friend class GrGLPathProcessor; |
| |
| typedef GrGLSLShaderBuilder 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 GrGLSLXPFragmentBuilder : public GrGLSLFragmentBuilder { |
| public: |
| GrGLSLXPFragmentBuilder(GrGLSLProgramBuilder* program) : INHERITED(program) {} |
| |
| /** Returns the variable name that holds the color of the destination pixel. This may be nullptr 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 GrGLSLFragmentBuilder INHERITED; |
| }; |
| |
| // TODO rename to Fragment Builder |
| class GrGLSLFragmentShaderBuilder : public GrGLSLXPFragmentBuilder { |
| public: |
| typedef uint8_t FragPosKey; |
| |
| /** 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); |
| |
| GrGLSLFragmentShaderBuilder(GrGLSLProgramBuilder* program, uint8_t fragPosKey); |
| |
| // true public interface, defined explicitly in the abstract interfaces above |
| bool enableFeature(GLSLFeature) override; |
| virtual SkString ensureFSCoords2D(const GrGLSLTransformedCoordsArray& 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; |
| |
| // As GLSLProcessors 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; |
| } |
| |
| static const char* DeclaredColorOutputName() { return "fsColorOut"; } |
| static const char* DeclaredSecondaryColorOutputName() { return "fsSecondaryColorOut"; } |
| |
| /* |
| * An internal call for GrGLProgramBuilder to use to add varyings to the vertex shader |
| */ |
| void addVarying(GrGLSLVarying*, GrSLPrecision); |
| |
| void onFinalize() override; |
| |
| /** |
| * Features that should only be enabled by GrGLSLFragmentShaderBuilder itself. |
| */ |
| enum GLSLPrivateFeature { |
| kFragCoordConventions_GLSLPrivateFeature = kLastGLSLFeature + 1, |
| kBlendEquationAdvanced_GLSLPrivateFeature, |
| kBlendFuncExtended_GLSLPrivateFeature, |
| kExternalTexture_GLSLPrivateFeature, |
| kLastGLSLPrivateFeature = kBlendFuncExtended_GLSLPrivateFeature |
| }; |
| |
| // 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 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 GrGLSLProgramBuilder; |
| friend class GrGLProgramBuilder; |
| |
| typedef GrGLSLXPFragmentBuilder INHERITED; |
| }; |
| |
| #endif |