1 /* 2 * Copyright 2012 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #ifndef GrGLEffect_DEFINED 9 #define GrGLEffect_DEFINED 10 11 #include "GrBackendEffectFactory.h" 12 #include "GrGLProgramEffects.h" 13 #include "GrGLShaderBuilder.h" 14 #include "GrGLShaderVar.h" 15 #include "GrGLSL.h" 16 17 /** @file 18 This file contains specializations for OpenGL of the shader stages declared in 19 include/gpu/GrEffect.h. Objects of type GrGLEffect are responsible for emitting the 20 GLSL code that implements a GrEffect and for uploading uniforms at draw time. If they don't 21 always emit the same GLSL code, they must have a function: 22 static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&) 23 that is used to implement a program cache. When two GrEffects produce the same key this means 24 that their GrGLEffects would emit the same GLSL code. 25 26 The GrGLEffect subclass must also have a constructor of the form: 27 EffectSubclass::EffectSubclass(const GrBackendEffectFactory&, const GrDrawEffect&) 28 The effect held by the GrDrawEffect is guaranteed to be of the type that generated the 29 GrGLEffect subclass instance. 30 31 These objects are created by the factory object returned by the GrEffect::getFactory(). 32 */ 33 34 class GrDrawEffect; 35 class GrGLTexture; 36 class GrGLVertexEffect; 37 38 class GrGLEffect { 39 40 public: 41 typedef GrBackendEffectFactory::EffectKey EffectKey; 42 typedef GrGLProgramEffects::TransformedCoordsArray TransformedCoordsArray; 43 typedef GrGLProgramEffects::TextureSampler TextureSampler; 44 typedef GrGLProgramEffects::TextureSamplerArray TextureSamplerArray; 45 46 enum { 47 kNoEffectKey = GrBackendEffectFactory::kNoEffectKey, 48 // the number of bits in EffectKey available to GenKey 49 kEffectKeyBits = GrBackendEffectFactory::kEffectKeyBits, 50 }; 51 GrGLEffect(const GrBackendEffectFactory & factory)52 GrGLEffect(const GrBackendEffectFactory& factory) 53 : fFactory(factory) 54 , fIsVertexEffect(false) { 55 } 56 ~GrGLEffect()57 virtual ~GrGLEffect() {} 58 59 /** Called when the program stage should insert its code into the shaders. The code in each 60 shader will be in its own block ({}) and so locally scoped names will not collide across 61 stages. 62 63 @param builder Interface used to emit code in the shaders. 64 @param drawEffect A wrapper on the effect that generated this program stage. 65 @param key The key that was computed by GenKey() from the generating GrEffect. 66 Only the bits indicated by GrBackendEffectFactory::kEffectKeyBits are 67 guaranteed to match the value produced by GenKey(); 68 @param outputColor A predefined vec4 in the FS in which the stage should place its output 69 color (or coverage). 70 @param inputColor A vec4 that holds the input color to the stage in the FS. This may be 71 NULL in which case the implied input is solid white (all ones). 72 TODO: Better system for communicating optimization info (e.g. input 73 color is solid white, trans black, known to be opaque, etc.) that allows 74 the effect to communicate back similar known info about its output. 75 @param samplers One entry for each GrTextureAccess of the GrEffect that generated the 76 GrGLEffect. These can be passed to the builder to emit texture 77 reads in the generated code. 78 */ 79 virtual void emitCode(GrGLShaderBuilder* builder, 80 const GrDrawEffect& drawEffect, 81 EffectKey key, 82 const char* outputColor, 83 const char* inputColor, 84 const TransformedCoordsArray& coords, 85 const TextureSamplerArray& samplers) = 0; 86 87 /** A GrGLEffect instance can be reused with any GrEffect that produces the same stage 88 key; this function reads data from a stage and uploads any uniform variables required 89 by the shaders created in emitCode(). The GrEffect installed in the GrEffectStage is 90 guaranteed to be of the same type that created this GrGLEffect and to have an identical 91 EffectKey as the one that created this GrGLEffect. Effects that use local coords have 92 to consider whether the GrEffectStage's coord change matrix should be used. When explicit 93 local coordinates are used it can be ignored. */ setData(const GrGLUniformManager &,const GrDrawEffect &)94 virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) {} 95 name()96 const char* name() const { return fFactory.name(); } 97 GenKey(const GrDrawEffect &,const GrGLCaps &)98 static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&) { return 0; } 99 100 /** Used by the system when generating shader code, to see if this effect can be downcasted to 101 the internal GrGLVertexEffect type */ isVertexEffect()102 bool isVertexEffect() const { return fIsVertexEffect; } 103 104 protected: 105 const GrBackendEffectFactory& fFactory; 106 107 private: 108 friend class GrGLVertexEffect; // to set fIsVertexEffect 109 110 bool fIsVertexEffect; 111 }; 112 113 #endif 114