2 * Copyright 2012 Google Inc.
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
8 #ifndef GrProcessor_DEFINED
9 #define GrProcessor_DEFINED
11 #include "GrBackendProcessorFactory.h"
13 #include "GrProcessorUnitTest.h"
14 #include "GrProgramElement.h"
15 #include "GrShaderVar.h"
16 #include "GrTextureAccess.h"
17 #include "GrTypesPriv.h"
20 class GrBackendProcessorFactory;
22 class GrCoordTransform;
24 /** Provides custom vertex shader, fragment shader, uniform data for a particular stage of the
25 Ganesh shading pipeline.
26 Subclasses must have a function that produces a human-readable name:
27 static const char* Name();
28 GrProcessor objects *must* be immutable: after being constructed, their fields may not change.
30 Dynamically allocated GrProcessors are managed by a per-thread memory pool. The ref count of an
31 effect must reach 0 before the thread terminates and the pool is destroyed. To create a static
32 effect use the macro GR_CREATE_STATIC_EFFECT declared below.
34 class GrProcessor : public GrProgramElement {
36 SK_DECLARE_INST_COUNT(GrProcessor)
38 virtual ~GrProcessor();
41 * This function is used to perform optimizations. When called the color and validFlags params
42 * indicate whether the input components to this effect in the FS will have known values.
43 * validFlags is a bitfield of GrColorComponentFlags. The function updates both params to
44 * indicate known values of its output. A component of the color param only has meaning if the
45 * corresponding bit in validFlags is set.
47 virtual void getConstantColorComponents(GrColor* color, uint32_t* validFlags) const = 0;
49 /** This object, besides creating back-end-specific helper objects, is used for run-time-type-
50 identification. The factory should be an instance of templated class,
51 GrTBackendEffectFactory. It is templated on the subclass of GrProcessor. The subclass must
52 have a nested type (or typedef) named GLProcessor which will be the subclass of
53 GrGLProcessor created by the factory.
56 class MyCustomEffect : public GrProcessor {
58 virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
59 return GrTBackendEffectFactory<MyCustomEffect>::getInstance();
64 virtual const GrBackendProcessorFactory& getFactory() const = 0;
66 /** Returns true if this and other effect conservatively draw identically. It can only return
67 true when the two effects are of the same subclass (i.e. they return the same object from
70 A return value of true from isEqual() should not be used to test whether the effects would
71 generate the same shader code. To test for identical code generation use the effects' keys
72 computed by the GrBackendEffectFactory.
74 bool isEqual(const GrProcessor& other) const {
75 if (&this->getFactory() != &other.getFactory()) {
78 bool result = this->onIsEqual(other);
81 this->assertEquality(other);
87 /** Human-meaningful string to identify this effect; may be embedded
88 in generated shader code. */
89 const char* name() const;
91 int numTransforms() const { return fCoordTransforms.count(); }
93 /** Returns the coordinate transformation at index. index must be valid according to
95 const GrCoordTransform& coordTransform(int index) const { return *fCoordTransforms[index]; }
97 int numTextures() const { return fTextureAccesses.count(); }
99 /** Returns the access pattern for the texture at index. index must be valid according to
101 const GrTextureAccess& textureAccess(int index) const { return *fTextureAccesses[index]; }
103 /** Shortcut for textureAccess(index).texture(); */
104 GrTexture* texture(int index) const { return this->textureAccess(index).getTexture(); }
106 /** Will this effect read the fragment position? */
107 bool willReadFragmentPosition() const { return fWillReadFragmentPosition; }
109 void* operator new(size_t size);
110 void operator delete(void* target);
112 void* operator new(size_t size, void* placement) {
113 return ::operator new(size, placement);
115 void operator delete(void* target, void* placement) {
116 ::operator delete(target, placement);
120 * Helper for down-casting to a GrProcessor subclass
122 template <typename T> const T& cast() const { return *static_cast<const T*>(this); }
126 * Subclasses call this from their constructor to register coordinate transformations. The
127 * effect subclass manages the lifetime of the transformations (this function only stores a
128 * pointer). The GrCoordTransform is typically a member field of the GrProcessor subclass. When
129 * the matrix has perspective, the transformed coordinates will have 3 components. Otherwise
130 * they'll have 2. This must only be called from the constructor because GrProcessors are
133 void addCoordTransform(const GrCoordTransform* coordTransform);
136 * Subclasses call this from their constructor to register GrTextureAccesses. The effect
137 * subclass manages the lifetime of the accesses (this function only stores a pointer). The
138 * GrTextureAccess is typically a member field of the GrProcessor subclass. This must only be
139 * called from the constructor because GrProcessors are immutable.
141 void addTextureAccess(const GrTextureAccess* textureAccess);
144 : fWillReadFragmentPosition(false) {}
147 * If the effect will generate a backend-specific effect that will read the fragment position
148 * in the FS then it must call this method from its constructor. Otherwise, the request to
149 * access the fragment position will be denied.
151 void setWillReadFragmentPosition() { fWillReadFragmentPosition = true; }
154 SkDEBUGCODE(void assertEquality(const GrProcessor& other) const;)
156 /** Subclass implements this to support isEqual(). It will only be called if it is known that
157 the two effects are of the same subclass (i.e. they return the same object from
159 virtual bool onIsEqual(const GrProcessor& other) const = 0;
161 friend class GrGeometryProcessor; // to set fRequiresVertexShader and build fVertexAttribTypes.
163 SkSTArray<4, const GrCoordTransform*, true> fCoordTransforms;
164 SkSTArray<4, const GrTextureAccess*, true> fTextureAccesses;
165 bool fWillReadFragmentPosition;
167 typedef GrProgramElement INHERITED;
170 class GrFragmentProcessor : public GrProcessor {
172 GrFragmentProcessor()
174 , fWillReadDstColor(false)
175 , fWillUseInputColor(true) {}
177 virtual const GrBackendFragmentProcessorFactory& getFactory() const = 0;
179 /** Will this effect read the destination pixel value? */
180 bool willReadDstColor() const { return fWillReadDstColor; }
182 /** Will this effect read the source color value? */
183 bool willUseInputColor() const { return fWillUseInputColor; }
187 * If the effect subclass will read the destination pixel value then it must call this function
188 * from its constructor. Otherwise, when its generated backend-specific effect class attempts
189 * to generate code that reads the destination pixel it will fail.
191 void setWillReadDstColor() { fWillReadDstColor = true; }
194 * If the effect will generate a result that does not depend on the input color value then it
195 * must call this function from its constructor. Otherwise, when its generated backend-specific
196 * code might fail during variable binding due to unused variables.
198 void setWillNotUseInputColor() { fWillUseInputColor = false; }
201 bool fWillReadDstColor;
202 bool fWillUseInputColor;
204 typedef GrProcessor INHERITED;
208 * This creates an effect outside of the effect memory pool. The effect's destructor will be called
209 * at global destruction time. NAME will be the name of the created GrProcessor.
211 #define GR_CREATE_STATIC_FRAGMENT_PROCESSOR(NAME, EFFECT_CLASS, ARGS) \
212 static SkAlignedSStorage<sizeof(EFFECT_CLASS)> g_##NAME##_Storage; \
213 static GrFragmentProcessor* \
214 NAME SkNEW_PLACEMENT_ARGS(g_##NAME##_Storage.get(), EFFECT_CLASS, ARGS); \
215 static SkAutoTDestroy<GrFragmentProcessor> NAME##_ad(NAME);