| /* |
| * 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 <tuple> |
| |
| #include "include/private/SkSLSampleUsage.h" |
| #include "src/gpu/GrProcessor.h" |
| |
| class GrGLSLFragmentProcessor; |
| class GrPaint; |
| class GrPipeline; |
| class GrProcessorKeyBuilder; |
| class GrShaderCaps; |
| class GrSwizzle; |
| class GrTextureEffect; |
| |
| /** Provides custom fragment shader code. Fragment processors receive an input position and |
| produce an output color. They may contain uniforms and may have children fragment processors |
| that are sampled. |
| */ |
| class GrFragmentProcessor : public GrProcessor { |
| public: |
| /** Always returns 'color'. */ |
| static std::unique_ptr<GrFragmentProcessor> MakeColor(SkPMColor4f color); |
| |
| /** |
| * 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 std::unique_ptr<GrFragmentProcessor> MulChildByInputAlpha( |
| std::unique_ptr<GrFragmentProcessor> child); |
| |
| /** |
| * Like MulChildByInputAlpha(), but reverses the sense of src and dst. In this case, return |
| * the input modulated by the child's alpha. The passed in FP will not receive an input color. |
| * |
| * output = input * child.a |
| */ |
| static std::unique_ptr<GrFragmentProcessor> MulInputByChildAlpha( |
| std::unique_ptr<GrFragmentProcessor> child); |
| |
| /** |
| * Returns a fragment processor that generates the passed-in color, modulated by the child's |
| * alpha channel. (Pass a null FP to use the alpha from fInputColor instead of a child FP.) |
| */ |
| static std::unique_ptr<GrFragmentProcessor> ModulateAlpha( |
| std::unique_ptr<GrFragmentProcessor> child, const SkPMColor4f& color); |
| |
| /** |
| * Returns a fragment processor that generates the passed-in color, modulated by the child's |
| * RGBA color. (Pass a null FP to use the color from fInputColor instead of a child FP.) |
| */ |
| static std::unique_ptr<GrFragmentProcessor> ModulateRGBA( |
| std::unique_ptr<GrFragmentProcessor> child, const SkPMColor4f& color); |
| |
| /** |
| * This assumes that the input color to the returned processor will be unpremul and that the |
| * passed processor (which becomes the returned processor's child) produces a premul output. |
| * The result of the returned processor is a premul of its input color modulated by the child |
| * processor's premul output. |
| */ |
| static std::unique_ptr<GrFragmentProcessor> MakeInputPremulAndMulByOutput( |
| std::unique_ptr<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 std::unique_ptr<GrFragmentProcessor> OverrideInput(std::unique_ptr<GrFragmentProcessor>, |
| const SkPMColor4f&, |
| bool useUniform = true); |
| |
| /** |
| * Returns a fragment processor that premuls the input before calling the passed in fragment |
| * processor. |
| */ |
| static std::unique_ptr<GrFragmentProcessor> PremulInput(std::unique_ptr<GrFragmentProcessor>); |
| |
| /** |
| * Returns a fragment processor that calls the passed in fragment processor, and then swizzles |
| * the output. |
| */ |
| static std::unique_ptr<GrFragmentProcessor> SwizzleOutput(std::unique_ptr<GrFragmentProcessor>, |
| const GrSwizzle&); |
| |
| /** |
| * Returns a fragment processor that calls the passed in fragment processor, and then ensures |
| * the output is a valid premul color by clamping RGB to [0, A]. |
| */ |
| static std::unique_ptr<GrFragmentProcessor> ClampPremulOutput( |
| std::unique_ptr<GrFragmentProcessor>); |
| |
| /** |
| * Returns a fragment processor that composes two fragment processors `f` and `g` into f(g(x)). |
| * This is equivalent to running them in series (`g`, then `f`). This is not the same as |
| * transfer-mode composition; there is no blending step. |
| */ |
| static std::unique_ptr<GrFragmentProcessor> Compose(std::unique_ptr<GrFragmentProcessor> f, |
| std::unique_ptr<GrFragmentProcessor> g); |
| |
| /** |
| * Returns a fragment processor that reads back the destination color; that is, sampling will |
| * return the color of the sample that is currently being painted over. |
| */ |
| static std::unique_ptr<GrFragmentProcessor> DestColor(); |
| |
| /** |
| * Makes a copy of this fragment processor that draws equivalently to the original. |
| * If the processor has child processors they are cloned as well. |
| */ |
| virtual std::unique_ptr<GrFragmentProcessor> clone() const = 0; |
| |
| // The FP this was registered with as a child function. This will be null if this is a root. |
| const GrFragmentProcessor* parent() const { return fParent; } |
| |
| std::unique_ptr<GrGLSLFragmentProcessor> makeProgramImpl() const; |
| |
| void getGLSLProcessorKey(const GrShaderCaps& caps, GrProcessorKeyBuilder* b) const { |
| this->onGetGLSLProcessorKey(caps, b); |
| for (const auto& child : fChildProcessors) { |
| if (child) { |
| child->getGLSLProcessorKey(caps, b); |
| } |
| } |
| } |
| |
| int numVaryingCoordsUsed() const { return this->usesVaryingCoordsDirectly() ? 1 : 0; } |
| |
| int numChildProcessors() const { return fChildProcessors.count(); } |
| int numNonNullChildProcessors() const; |
| |
| GrFragmentProcessor* childProcessor(int index) { return fChildProcessors[index].get(); } |
| const GrFragmentProcessor* childProcessor(int index) const { |
| return fChildProcessors[index].get(); |
| } |
| |
| SkDEBUGCODE(bool isInstantiated() const;) |
| |
| /** |
| * Does this FP require local coordinates to be produced by the primitive processor? This only |
| * returns true if this FP will directly read those local coordinates. FPs that are sampled |
| * explicitly do not require primitive-generated local coordinates (because the sample |
| * coordinates are supplied by the parent FP). |
| * |
| * If the root of an FP tree does not provide explicit coordinates, the geometry processor |
| * provides the original local coordinates to start. This may be implicit as part of vertex |
| * shader-lifted varyings, or by providing the base local coordinate to the fragment shader. |
| */ |
| bool usesVaryingCoordsDirectly() const { |
| return SkToBool(fFlags & kUsesSampleCoordsDirectly_Flag) && |
| !SkToBool(fFlags & kSampledWithExplicitCoords_Flag); |
| } |
| |
| /** |
| * Do any of the FPs in this tree require local coordinates to be produced by the primitive |
| * processor? This can return true even if this FP does not refer to sample coordinates, but |
| * true if a descendant FP uses them. |
| */ |
| bool usesVaryingCoords() const { |
| return (SkToBool(fFlags & kUsesSampleCoordsDirectly_Flag) || |
| SkToBool(fFlags & kUsesSampleCoordsIndirectly_Flag)) && |
| !SkToBool(fFlags & kSampledWithExplicitCoords_Flag); |
| } |
| |
| /** Do any of the FPs in this tree read back the color from the destination surface? */ |
| bool willReadDstColor() const { |
| return SkToBool(fFlags & kWillReadDstColor_Flag); |
| } |
| |
| /** |
| * True if this FP refers directly to the sample coordinate parameter of its function |
| * (e.g. uses EmitArgs::fSampleCoord in emitCode()). This also returns true if the |
| * coordinate reference comes from autogenerated code invoking 'sample(matrix)' expressions. |
| * |
| * Unlike usesVaryingCoords(), this can return true whether or not the FP is explicitly |
| * sampled, and does not change based on how the FP is composed. This property is specific to |
| * the FP's function and not the entire program. |
| */ |
| bool referencesSampleCoords() const { |
| return SkToBool(fFlags & kUsesSampleCoordsDirectly_Flag); |
| } |
| |
| // True if this FP's parent invokes it with 'sample(float2)' or a variable 'sample(matrix)' |
| bool isSampledWithExplicitCoords() const { |
| return SkToBool(fFlags & kSampledWithExplicitCoords_Flag); |
| } |
| |
| // True if the transform chain from root to this FP introduces perspective into the local |
| // coordinate expression. |
| bool hasPerspectiveTransform() const { |
| return SkToBool(fFlags & kNetTransformHasPerspective_Flag); |
| } |
| |
| // The SampleUsage describing how this FP is invoked by its parent using 'sample(matrix)' |
| // This only reflects the immediate sampling from parent to this FP |
| const SkSL::SampleUsage& sampleUsage() const { |
| return fUsage; |
| } |
| |
| /** |
| * A GrDrawOp may premultiply its antialiasing coverage into its GrGeometryProcessor's color |
| * output under the following scenario: |
| * * all the color fragment processors report true to this query, |
| * * all the coverage fragment processors report true to this query, |
| * * the blend mode arithmetic allows for it it. |
| * To be compatible a fragment processor's output must be a modulation of its input color or |
| * alpha with a computed premultiplied color or alpha that is in 0..1 range. The computed color |
| * or alpha that is modulated against the input cannot depend on the input's alpha. The computed |
| * value cannot depend on the input's color channels unless it unpremultiplies the input color |
| * channels by the input alpha. |
| */ |
| bool compatibleWithCoverageAsAlpha() const { |
| return SkToBool(fFlags & kCompatibleWithCoverageAsAlpha_OptimizationFlag); |
| } |
| |
| /** |
| * If this is true then all opaque input colors to the processor produce opaque output colors. |
| */ |
| bool preservesOpaqueInput() const { |
| return SkToBool(fFlags & kPreservesOpaqueInput_OptimizationFlag); |
| } |
| |
| /** |
| * Tests whether given a constant input color the processor produces a constant output color |
| * (for all fragments). If true outputColor will contain the constant color produces for |
| * inputColor. |
| */ |
| bool hasConstantOutputForConstantInput(SkPMColor4f inputColor, SkPMColor4f* outputColor) const { |
| if (fFlags & kConstantOutputForConstantInput_OptimizationFlag) { |
| *outputColor = this->constantOutputForConstantInput(inputColor); |
| return true; |
| } |
| return false; |
| } |
| bool hasConstantOutputForConstantInput() const { |
| return SkToBool(fFlags & kConstantOutputForConstantInput_OptimizationFlag); |
| } |
| |
| /** 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; |
| |
| void visitProxies(const GrVisitProxyFunc&) const; |
| |
| void visitTextureEffects(const std::function<void(const GrTextureEffect&)>&) const; |
| |
| GrTextureEffect* asTextureEffect(); |
| const GrTextureEffect* asTextureEffect() const; |
| |
| #if GR_TEST_UTILS |
| // Generates debug info for this processor tree by recursively calling dumpInfo() on this |
| // processor and its children. |
| SkString dumpTreeInfo() const; |
| #endif |
| |
| // A pre-order traversal iterator over a hierarchy of FPs. It can also iterate over all the FP |
| // hierarchies rooted in a GrPaint, GrProcessorSet, or GrPipeline. For these collections it |
| // iterates the tree rooted at each color FP and then each coverage FP. |
| // |
| // An iterator is constructed from one of the srcs and used like this: |
| // for (GrFragmentProcessor::Iter iter(pipeline); iter; ++iter) { |
| // GrFragmentProcessor& fp = *iter; |
| // } |
| // The exit test for the loop is using CIter's operator bool(). |
| // To use a range-for loop instead see CIterRange below. |
| class CIter; |
| |
| // Used to implement a range-for loop using CIter. Src is one of GrFragmentProcessor, |
| // GrPaint, GrProcessorSet, or GrPipeline. Type aliases for these defined below. |
| // Example usage: |
| // for (const auto& fp : GrFragmentProcessor::PaintRange(paint)) { |
| // if (fp.usesLocalCoords()) { |
| // ... |
| // } |
| // } |
| template <typename Src> class CIterRange; |
| |
| // We would use template deduction guides for CIter but for: |
| // https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79501 |
| // Instead we use these specialized type aliases to make it prettier |
| // to construct CIters for particular sources of FPs. |
| using FPRange = CIterRange<GrFragmentProcessor>; |
| using PaintRange = CIterRange<GrPaint>; |
| |
| // Sentinel type for range-for using CIter. |
| class EndCIter {}; |
| |
| protected: |
| enum OptimizationFlags : uint32_t { |
| kNone_OptimizationFlags, |
| kCompatibleWithCoverageAsAlpha_OptimizationFlag = 0x1, |
| kPreservesOpaqueInput_OptimizationFlag = 0x2, |
| kConstantOutputForConstantInput_OptimizationFlag = 0x4, |
| kAll_OptimizationFlags = kCompatibleWithCoverageAsAlpha_OptimizationFlag | |
| kPreservesOpaqueInput_OptimizationFlag | |
| kConstantOutputForConstantInput_OptimizationFlag |
| }; |
| GR_DECL_BITFIELD_OPS_FRIENDS(OptimizationFlags) |
| |
| /** |
| * Can be used as a helper to decide which fragment processor OptimizationFlags should be set. |
| * This assumes that the subclass output color will be a modulation of the input color with a |
| * value read from a texture of the passed color type and that the texture contains |
| * premultiplied color or alpha values that are in range. |
| * |
| * Since there are multiple ways in which a sampler may have its coordinates clamped or wrapped, |
| * callers must determine on their own if the sampling uses a decal strategy in any way, in |
| * which case the texture may become transparent regardless of the color type. |
| */ |
| static OptimizationFlags ModulateForSamplerOptFlags(SkAlphaType alphaType, bool samplingDecal) { |
| if (samplingDecal) { |
| return kCompatibleWithCoverageAsAlpha_OptimizationFlag; |
| } else { |
| return ModulateForClampedSamplerOptFlags(alphaType); |
| } |
| } |
| |
| // As above, but callers should somehow ensure or assert their sampler still uses clamping |
| static OptimizationFlags ModulateForClampedSamplerOptFlags(SkAlphaType alphaType) { |
| if (alphaType == kOpaque_SkAlphaType) { |
| return kCompatibleWithCoverageAsAlpha_OptimizationFlag | |
| kPreservesOpaqueInput_OptimizationFlag; |
| } else { |
| return kCompatibleWithCoverageAsAlpha_OptimizationFlag; |
| } |
| } |
| |
| GrFragmentProcessor(ClassID classID, OptimizationFlags optimizationFlags) |
| : INHERITED(classID), fFlags(optimizationFlags) { |
| SkASSERT((optimizationFlags & ~kAll_OptimizationFlags) == 0); |
| } |
| |
| OptimizationFlags optimizationFlags() const { |
| return static_cast<OptimizationFlags>(kAll_OptimizationFlags & fFlags); |
| } |
| |
| /** Useful when you can't call fp->optimizationFlags() on a base class object from a subclass.*/ |
| static OptimizationFlags ProcessorOptimizationFlags(const GrFragmentProcessor* fp) { |
| return fp ? fp->optimizationFlags() : kAll_OptimizationFlags; |
| } |
| |
| /** |
| * This allows one subclass to access another subclass's implementation of |
| * constantOutputForConstantInput. It must only be called when |
| * hasConstantOutputForConstantInput() is known to be true. |
| */ |
| static SkPMColor4f ConstantOutputForConstantInput(const GrFragmentProcessor* fp, |
| const SkPMColor4f& input) { |
| if (fp) { |
| SkASSERT(fp->hasConstantOutputForConstantInput()); |
| return fp->constantOutputForConstantInput(input); |
| } else { |
| return input; |
| } |
| } |
| |
| /** |
| * 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. |
| * |
| * The SampleUsage parameter describes all of the ways that the child is sampled by the parent. |
| */ |
| void registerChild(std::unique_ptr<GrFragmentProcessor> child, |
| SkSL::SampleUsage sampleUsage = SkSL::SampleUsage::PassThrough()); |
| |
| /** |
| * This method takes an existing fragment processor, clones all of its children, and registers |
| * the clones as children of this fragment processor. |
| */ |
| void cloneAndRegisterAllChildProcessors(const GrFragmentProcessor& src); |
| |
| // FP implementations must call this function if their matching GrGLSLFragmentProcessor's |
| // emitCode() function uses the EmitArgs::fSampleCoord variable in generated SkSL. |
| void setUsesSampleCoordsDirectly() { |
| fFlags |= kUsesSampleCoordsDirectly_Flag; |
| } |
| |
| // FP implementations must set this flag if their GrGLSLFragmentProcessor's emitCode() function |
| // calls dstColor() to read back the framebuffer. |
| void setWillReadDstColor() { |
| fFlags |= kWillReadDstColor_Flag; |
| } |
| |
| void mergeOptimizationFlags(OptimizationFlags flags) { |
| SkASSERT((flags & ~kAll_OptimizationFlags) == 0); |
| fFlags &= (flags | ~kAll_OptimizationFlags); |
| } |
| |
| private: |
| virtual SkPMColor4f constantOutputForConstantInput(const SkPMColor4f& /* inputColor */) const { |
| SK_ABORT("Subclass must override this if advertising this optimization."); |
| } |
| |
| /** Returns a new instance of the appropriate *GL* implementation class |
| for the given GrFragmentProcessor; caller is responsible for deleting |
| the object. */ |
| virtual std::unique_ptr<GrGLSLFragmentProcessor> onMakeProgramImpl() const = 0; |
| |
| /** Implemented using GLFragmentProcessor::GenKey as described in this class's comment. */ |
| virtual void onGetGLSLProcessorKey(const GrShaderCaps&, GrProcessorKeyBuilder*) 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()). |
| */ |
| virtual bool onIsEqual(const GrFragmentProcessor&) const = 0; |
| |
| enum PrivateFlags { |
| kFirstPrivateFlag = kAll_OptimizationFlags + 1, |
| |
| // Propagates up the FP tree to the root |
| kUsesSampleCoordsIndirectly_Flag = kFirstPrivateFlag, |
| |
| // Does not propagate at all |
| kUsesSampleCoordsDirectly_Flag = kFirstPrivateFlag << 1, |
| |
| // Propagates down the FP to all its leaves |
| kSampledWithExplicitCoords_Flag = kFirstPrivateFlag << 2, |
| kNetTransformHasPerspective_Flag = kFirstPrivateFlag << 3, |
| |
| // Propagates up the FP tree to the root |
| kWillReadDstColor_Flag = kFirstPrivateFlag << 4, |
| }; |
| void addAndPushFlagToChildren(PrivateFlags flag); |
| |
| SkSTArray<1, std::unique_ptr<GrFragmentProcessor>, true> fChildProcessors; |
| const GrFragmentProcessor* fParent = nullptr; |
| uint32_t fFlags = 0; |
| SkSL::SampleUsage fUsage; |
| |
| using INHERITED = GrProcessor; |
| }; |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| GR_MAKE_BITFIELD_OPS(GrFragmentProcessor::OptimizationFlags) |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| class GrFragmentProcessor::CIter { |
| public: |
| explicit CIter(const GrFragmentProcessor& fp) { fFPStack.push_back(&fp); } |
| explicit CIter(const GrPaint&); |
| explicit CIter(const GrPipeline&); |
| |
| const GrFragmentProcessor& operator*() const { return *fFPStack.back(); } |
| const GrFragmentProcessor* operator->() const { return fFPStack.back(); } |
| |
| CIter& operator++(); |
| |
| operator bool() const { return !fFPStack.empty(); } |
| |
| bool operator!=(const EndCIter&) { return (bool)*this; } |
| |
| // Hopefully this does not actually get called because of RVO. |
| CIter(const CIter&) = default; |
| |
| // Because each iterator carries a stack we want to avoid copies. |
| CIter& operator=(const CIter&) = delete; |
| |
| protected: |
| CIter() = delete; |
| |
| SkSTArray<4, const GrFragmentProcessor*, true> fFPStack; |
| }; |
| |
| ////////////////////////////////////////////////////////////////////////////// |
| |
| template <typename Src> class GrFragmentProcessor::CIterRange { |
| public: |
| explicit CIterRange(const Src& t) : fT(t) {} |
| CIter begin() const { return CIter(fT); } |
| EndCIter end() const { return EndCIter(); } |
| |
| private: |
| const Src& fT; |
| }; |
| |
| /** |
| * Some fragment-processor creation methods have preconditions that might not be satisfied by the |
| * calling code. Those methods can return a `GrFPResult` from their factory methods. If creation |
| * succeeds, the new fragment processor is created and `success` is true. If a precondition is not |
| * met, `success` is set to false and the input FP is returned unchanged. |
| */ |
| using GrFPResult = std::tuple<bool /*success*/, std::unique_ptr<GrFragmentProcessor>>; |
| static inline GrFPResult GrFPFailure(std::unique_ptr<GrFragmentProcessor> fp) { |
| return {false, std::move(fp)}; |
| } |
| static inline GrFPResult GrFPSuccess(std::unique_ptr<GrFragmentProcessor> fp) { |
| SkASSERT(fp); |
| return {true, std::move(fp)}; |
| } |
| |
| #endif |