| /* |
| * 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; |
| class GrGLSLCaps; |
| class GrGLSLFragmentProcessor; |
| class GrInvariantOutput; |
| class GrProcessorKeyBuilder; |
| |
| /** 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: |
| /** |
| * In many instances (e.g. SkShader::asFragmentProcessor() implementations) it is desirable to |
| * only consider the input color's alpha. However, there is a competing desire to have reusable |
| * GrFragmentProcessor subclasses that can be used in other scenarios where the entire input |
| * color is considered. This function exists to filter the input color and pass it to a FP. It |
| * does so by returning a parent FP that multiplies the passed in FPs output by the parent's |
| * input alpha. The passed in FP will not receive an input color. |
| */ |
| static const GrFragmentProcessor* MulOutputByInputAlpha(const GrFragmentProcessor*); |
| |
| /** |
| * Similar to the above but it modulates the output r,g,b of the child processor by the input |
| * rgb and then multiplies all the components by the input alpha. This effectively modulates |
| * the child processor's premul color by a unpremul'ed input and produces a premul output |
| */ |
| static const GrFragmentProcessor* MulOutputByInputUnpremulColor(const GrFragmentProcessor*); |
| |
| /** |
| * Returns a parent fragment processor that adopts the passed fragment processor as a child. |
| * The parent will ignore its input color and instead feed the passed in color as input to the |
| * child. |
| */ |
| static const GrFragmentProcessor* OverrideInput(const GrFragmentProcessor*, GrColor); |
| |
| /** |
| * Returns a fragment processor that runs the passed in array of fragment processors in a |
| * series. The original input is passed to the first, the first's output is passed to the |
| * second, etc. The output of the returned processor is the output of the last processor of the |
| * series. |
| */ |
| static const GrFragmentProcessor* RunInSeries(const GrFragmentProcessor*[], int cnt); |
| |
| GrFragmentProcessor() |
| : INHERITED() |
| , fUsesLocalCoords(false) |
| , fNumTexturesExclChildren(0) |
| , fNumTransformsExclChildren(0) {} |
| |
| ~GrFragmentProcessor() override; |
| |
| GrGLSLFragmentProcessor* createGLInstance() const; |
| |
| void getGLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const { |
| this->onGetGLProcessorKey(caps, b); |
| for (int i = 0; i < fChildProcessors.count(); ++i) { |
| fChildProcessors[i]->getGLProcessorKey(caps, b); |
| } |
| } |
| |
| int numTexturesExclChildren() const { return fNumTexturesExclChildren; } |
| |
| int numTransformsExclChildren() const { return fNumTransformsExclChildren; } |
| |
| 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]; } |
| |
| const SkTArray<const GrCoordTransform*, true>& coordTransforms() const { |
| return fCoordTransforms; |
| } |
| |
| void gatherCoordTransforms(SkTArray<const GrCoordTransform*, true>* outTransforms) const { |
| if (!fCoordTransforms.empty()) { |
| outTransforms->push_back_n(fCoordTransforms.count(), fCoordTransforms.begin()); |
| } |
| } |
| |
| int numChildProcessors() const { return fChildProcessors.count(); } |
| |
| const GrFragmentProcessor& childProcessor(int index) const { return *fChildProcessors[index]; } |
| |
| /** Do any of the coordtransforms for this processor require local coords? */ |
| bool usesLocalCoords() const { return fUsesLocalCoords; } |
| |
| /** Returns true if this and other processor conservatively draw identically. It can only return |
| true when the two processor 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 processor would |
| generate the same shader code. To test for identical code generation use getGLProcessorKey*/ |
| bool isEqual(const GrFragmentProcessor& that, bool ignoreCoordTransforms) const; |
| |
| /** |
| * This function is used to perform optimizations. When called the invarientOuput param |
| * indicate whether the input components to this processor in the FS will have known values. |
| * In inout the validFlags member is a bitfield of GrColorComponentFlags. The isSingleComponent |
| * member indicates whether the input will be 1 or 4 bytes. The function updates the members of |
| * inout to indicate known values of its output. A component of the color member only has |
| * meaning if the corresponding bit in validFlags is set. |
| */ |
| void computeInvariantOutput(GrInvariantOutput* inout) const { |
| this->onComputeInvariantOutput(inout); |
| } |
| |
| protected: |
| void addTextureAccess(const GrTextureAccess* textureAccess) override; |
| |
| /** |
| * Fragment Processor subclasses call this from their constructor to register coordinate |
| * transformations. Coord transforms provide a mechanism for a processor to receive coordinates |
| * in their FS code. The matrix expresses a transformation from local space. For a given |
| * fragment the matrix will be applied to the local coordinate that maps to the fragment. |
| * |
| * When the transformation 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. 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. |
| * |
| * A processor subclass that has multiple methods of construction should always add its coord |
| * transforms in a consistent order. The non-virtual implementation of isEqual() automatically |
| * compares transforms and will assume they line up across the two processor instances. |
| */ |
| void addCoordTransform(const GrCoordTransform*); |
| |
| /** |
| * FragmentProcessor subclasses call this from their constructor to register any child |
| * FragmentProcessors they have. This must be called AFTER all texture accesses and coord |
| * transforms have been added. |
| * This is for processors whose shader code will be composed of nested processors whose output |
| * colors will be combined somehow to produce its output color. Registering these child |
| * processors will allow the ProgramBuilder to automatically handle their transformed coords and |
| * texture accesses and mangle their uniform and output color names. |
| */ |
| int registerChildProcessor(const GrFragmentProcessor* child); |
| |
| /** |
| * Subclass implements this to support getConstantColorComponents(...). |
| * |
| * Note: it's up to the subclass implementation to do any recursive call to compute the child |
| * procs' output invariants; computeInvariantOutput will not be recursive. |
| */ |
| virtual void onComputeInvariantOutput(GrInvariantOutput* inout) const = 0; |
| |
| private: |
| void notifyRefCntIsZero() const final; |
| |
| /** Returns a new instance of the appropriate *GL* implementation class |
| for the given GrFragmentProcessor; caller is responsible for deleting |
| the object. */ |
| virtual GrGLSLFragmentProcessor* onCreateGLInstance() const = 0; |
| |
| /** Implemented using GLFragmentProcessor::GenKey as described in this class's comment. */ |
| virtual void onGetGLProcessorKey(const GrGLSLCaps& caps, |
| GrProcessorKeyBuilder* b) const = 0; |
| |
| /** |
| * Subclass implements this to support isEqual(). It will only be called if it is known that |
| * the two processors are of the same subclass (i.e. they return the same object from |
| * getFactory()). The processor subclass should not compare its coord transforms as that will |
| * be performed automatically in the non-virtual isEqual(). |
| */ |
| virtual bool onIsEqual(const GrFragmentProcessor&) const = 0; |
| |
| bool hasSameTransforms(const GrFragmentProcessor&) const; |
| |
| bool fUsesLocalCoords; |
| |
| /** |
| * fCoordTransforms stores the transforms of this proc, followed by all the transforms of this |
| * proc's children. In other words, each proc stores all the transforms of its subtree as if |
| * they were collected using preorder traversal. |
| * |
| * Example: |
| * Suppose we have frag proc A, who has two children B and D. B has a child C, and D has |
| * two children E and F. Suppose procs A, B, C, D, E, F have 1, 2, 1, 1, 3, 2 transforms |
| * respectively. The following shows what the fCoordTransforms array of each proc would contain: |
| * |
| * (A) |
| * [a1,b1,b2,c1,d1,e1,e2,e3,f1,f2] |
| * / \ |
| * / \ |
| * (B) (D) |
| * [b1,b2,c1] [d1,e1,e2,e3,f1,f2] |
| * / / \ |
| * / / \ |
| * (C) (E) (F) |
| * [c1] [e1,e2,e3] [f1,f2] |
| * |
| * The same goes for fTextureAccesses with textures. |
| */ |
| SkSTArray<4, const GrCoordTransform*, true> fCoordTransforms; |
| |
| int fNumTexturesExclChildren; |
| int fNumTransformsExclChildren; |
| |
| // TODO: These must convert their processors to pending-execution refs when the parent is |
| // converted (do this automatically in GrProgramElement?). |
| SkTArray<const GrFragmentProcessor*, true> fChildProcessors; |
| |
| typedef GrProcessor INHERITED; |
| }; |
| |
| #endif |