| /* |
| * 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 GrFragmentProcessor_DEFINED |
| #define GrFragmentProcessor_DEFINED |
| |
| #include "GrProcessor.h" |
| |
| class GrCoordTransform; |
| |
| /** Provides custom fragment shader code. Fragment processors receive an input color (vec4f) and |
| produce an output color. They may reference textures and uniforms. They may use |
| GrCoordTransforms to receive a transformation of the local coordinates that map from local space |
| to the fragment being processed. |
| */ |
| class GrFragmentProcessor : public GrProcessor { |
| public: |
| GrFragmentProcessor() |
| : INHERITED() |
| , fWillReadDstColor(false) |
| , fWillUseInputColor(true) {} |
| |
| virtual const GrBackendFragmentProcessorFactory& getFactory() const = 0; |
| |
| int numTransforms() const { return fCoordTransforms.count(); } |
| |
| /** Returns the coordinate transformation at index. index must be valid according to |
| numTransforms(). */ |
| const GrCoordTransform& coordTransform(int index) const { return *fCoordTransforms[index]; } |
| |
| /** Will this prceossor read the destination pixel value? */ |
| bool willReadDstColor() const { return fWillReadDstColor; } |
| |
| /** Will this prceossor read the source color value? */ |
| bool willUseInputColor() const { return fWillUseInputColor; } |
| |
| /** Returns true if this and other prceossor conservatively draw identically. It can only return |
| true when the two prceossor are of the same subclass (i.e. they return the same object from |
| from getFactory()). |
| |
| A return value of true from isEqual() should not be used to test whether the prceossor would |
| generate the same shader code. To test for identical code generation use the prceossor' keys |
| computed by the GrBackendProcessorFactory. */ |
| bool isEqual(const GrFragmentProcessor& other) const { |
| if (&this->getFactory() != &other.getFactory()) { |
| return false; |
| } |
| bool result = this->onIsEqual(other); |
| #ifdef SK_DEBUG |
| if (result) { |
| this->assertTexturesEqual(other); |
| } |
| #endif |
| return result; |
| } |
| |
| protected: |
| /** |
| * Fragment Processor subclasses call this from their constructor to register coordinate |
| * transformations. The processor subclass manages the lifetime of the transformations (this |
| * function only stores a pointer). The GrCoordTransform is typically a member field of the |
| * GrProcessor subclass. When the matrix has perspective, the transformed coordinates will have |
| * 3 components. Otherwise they'll have 2. This must only be called from the constructor because |
| * GrProcessors are immutable. |
| */ |
| void addCoordTransform(const GrCoordTransform*); |
| |
| /** |
| * If the prceossor subclass will read the destination pixel value then it must call this function |
| * from its constructor. Otherwise, when its generated backend-specific prceossor class attempts |
| * to generate code that reads the destination pixel it will fail. |
| */ |
| void setWillReadDstColor() { fWillReadDstColor = true; } |
| |
| /** |
| * If the prceossor will generate a result that does not depend on the input color value then it |
| * must call this function from its constructor. Otherwise, when its generated backend-specific |
| * code might fail during variable binding due to unused variables. |
| */ |
| void setWillNotUseInputColor() { fWillUseInputColor = false; } |
| |
| private: |
| /** Subclass implements this to support isEqual(). It will only be called if it is known that |
| the two prceossor are of the same subclass (i.e. they return the same object from |
| getFactory()).*/ |
| virtual bool onIsEqual(const GrFragmentProcessor& other) const = 0; |
| |
| SkSTArray<4, const GrCoordTransform*, true> fCoordTransforms; |
| bool fWillReadDstColor; |
| bool fWillUseInputColor; |
| |
| typedef GrProcessor INHERITED; |
| }; |
| |
| /** |
| * This creates an effect outside of the effect memory pool. The effect's destructor will be called |
| * at global destruction time. NAME will be the name of the created GrProcessor. |
| */ |
| #define GR_CREATE_STATIC_FRAGMENT_PROCESSOR(NAME, FP_CLASS, ARGS) \ |
| static SkAlignedSStorage<sizeof(FP_CLASS)> g_##NAME##_Storage; \ |
| static GrFragmentProcessor* NAME SkNEW_PLACEMENT_ARGS(g_##NAME##_Storage.get(), FP_CLASS, ARGS); \ |
| static SkAutoTDestroy<GrFragmentProcessor> NAME##_ad(NAME); |
| |
| #endif |