| /* |
| * 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 GrPipeline; |
| 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 sk_sp<GrFragmentProcessor> MulOutputByInputAlpha(sk_sp<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 sk_sp<GrFragmentProcessor> MulOutputByInputUnpremulColor(sk_sp<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 sk_sp<GrFragmentProcessor> OverrideInput(sk_sp<GrFragmentProcessor>, GrColor4f); |
| |
| /** |
| * Returns a fragment processor that premuls the input before calling the passed in fragment |
| * processor. |
| */ |
| static sk_sp<GrFragmentProcessor> PremulInput(sk_sp<GrFragmentProcessor>); |
| |
| /** |
| * 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. |
| * |
| * The array elements with be moved. |
| */ |
| static sk_sp<GrFragmentProcessor> RunInSeries(sk_sp<GrFragmentProcessor>*, int cnt); |
| |
| GrFragmentProcessor() |
| : INHERITED() |
| , fUsesDistanceVectorField(false) |
| , fUsesLocalCoords(false) {} |
| |
| ~GrFragmentProcessor() override; |
| |
| GrGLSLFragmentProcessor* createGLSLInstance() const; |
| |
| void getGLSLProcessorKey(const GrGLSLCaps& caps, GrProcessorKeyBuilder* b) const { |
| this->onGetGLSLProcessorKey(caps, b); |
| for (int i = 0; i < fChildProcessors.count(); ++i) { |
| fChildProcessors[i]->getGLSLProcessorKey(caps, b); |
| } |
| } |
| |
| int numCoordTransforms() 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; |
| } |
| |
| 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; } |
| |
| /** Does this FP need a vector to the nearest edge? */ |
| bool usesDistanceVectorField() const { return fUsesDistanceVectorField; } |
| |
| /** 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 getGLSLProcessorKey |
| */ |
| bool isEqual(const GrFragmentProcessor& that) 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); |
| } |
| |
| /** |
| * Pre-order traversal of a FP hierarchy, or of the forest of FPs in a GrPipeline. In the latter |
| * case the tree rooted at each FP in the GrPipeline is visited successively. |
| */ |
| class Iter : public SkNoncopyable { |
| public: |
| explicit Iter(const GrFragmentProcessor* fp) { fFPStack.push_back(fp); } |
| explicit Iter(const GrPipeline& pipeline); |
| const GrFragmentProcessor* next(); |
| |
| private: |
| SkSTArray<4, const GrFragmentProcessor*, true> fFPStack; |
| }; |
| |
| /** |
| * Iterates over all the Ts owned by a GrFragmentProcessor and its children or over all the Ts |
| * owned by the forest of GrFragmentProcessors in a GrPipeline. FPs are visited in the same |
| * order as Iter and each of an FP's Ts are visited in order. |
| */ |
| template <typename T, typename BASE, |
| int (BASE::*COUNT)() const, |
| const T& (BASE::*GET)(int) const> |
| class FPItemIter : public SkNoncopyable { |
| public: |
| explicit FPItemIter(const GrFragmentProcessor* fp) |
| : fCurrFP(nullptr) |
| , fCTIdx(0) |
| , fFPIter(fp) { |
| fCurrFP = fFPIter.next(); |
| } |
| explicit FPItemIter(const GrPipeline& pipeline) |
| : fCurrFP(nullptr) |
| , fCTIdx(0) |
| , fFPIter(pipeline) { |
| fCurrFP = fFPIter.next(); |
| } |
| |
| const T* next() { |
| if (!fCurrFP) { |
| return nullptr; |
| } |
| while (fCTIdx == (fCurrFP->*COUNT)()) { |
| fCTIdx = 0; |
| fCurrFP = fFPIter.next(); |
| if (!fCurrFP) { |
| return nullptr; |
| } |
| } |
| return &(fCurrFP->*GET)(fCTIdx++); |
| } |
| |
| private: |
| const GrFragmentProcessor* fCurrFP; |
| int fCTIdx; |
| GrFragmentProcessor::Iter fFPIter; |
| }; |
| |
| using CoordTransformIter = FPItemIter<GrCoordTransform, |
| GrFragmentProcessor, |
| &GrFragmentProcessor::numCoordTransforms, |
| &GrFragmentProcessor::coordTransform>; |
| |
| using TextureAccessIter = FPItemIter<TextureSampler, |
| GrProcessor, |
| &GrProcessor::numTextureSamplers, |
| &GrProcessor::textureSampler>; |
| |
| protected: |
| /** |
| * 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(sk_sp<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; |
| |
| /* Sub-classes should set this to true in their constructors if they need access to a distance |
| * vector field to the nearest edge |
| */ |
| bool fUsesDistanceVectorField; |
| |
| 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* onCreateGLSLInstance() const = 0; |
| |
| /** Implemented using GLFragmentProcessor::GenKey as described in this class's comment. */ |
| virtual void onGetGLSLProcessorKey(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; |
| |
| SkSTArray<4, const GrCoordTransform*, true> fCoordTransforms; |
| |
| /** |
| * This is not SkSTArray<1, sk_sp<GrFragmentProcessor>> because this class holds strong |
| * references until notifyRefCntIsZero and then it holds pending executions. |
| */ |
| SkSTArray<1, GrFragmentProcessor*, true> fChildProcessors; |
| |
| typedef GrProcessor INHERITED; |
| }; |
| |
| #endif |