2eaaefd7e6
R=robertphillips@google.com Review URL: https://codereview.appspot.com/6819046 git-svn-id: http://skia.googlecode.com/svn/branches/gpu_dev@6182 2bbb7eff-a529-9590-31e7-b0007b416f81
98 lines
3.4 KiB
C++
98 lines
3.4 KiB
C++
/*
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* Copyright 2012 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef GrEffect_DEFINED
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#define GrEffect_DEFINED
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#include "GrRefCnt.h"
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#include "GrNoncopyable.h"
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#include "GrEffectUnitTest.h"
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#include "GrTextureAccess.h"
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class GrBackendEffectFactory;
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class GrContext;
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class GrTexture;
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class SkString;
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/** Provides custom vertex shader, fragment shader, uniform data for a
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particular stage of the Ganesh shading pipeline.
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Subclasses must have a function that produces a human-readable name:
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static const char* Name();
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GrEffect objects *must* be immutable: after being constructed,
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their fields may not change. (Immutability isn't actually required
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until they've been used in a draw call, but supporting that would require
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setters and getters that could fail, copy-on-write, or deep copying of these
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objects when they're stored by a GrGLEffect.)
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*/
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class GrEffect : public GrRefCnt {
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public:
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SK_DECLARE_INST_COUNT(GrEffect)
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explicit GrEffect(int numTextures);
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virtual ~GrEffect();
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/** If given an input texture that is/is not opaque, is this
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effect guaranteed to produce an opaque output? */
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virtual bool isOpaque(bool inputTextureIsOpaque) const;
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/** This object, besides creating back-end-specific helper objects, is used for run-time-type-
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identification. The factory should be an instance of templated class,
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GrTBackendEffectFactory. It is templated on the subclass of GrEffect. The subclass must have
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a nested type (or typedef) named GLEffect which will be the subclass of GrGLEffect created
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by the factory.
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Example:
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class MyCustomEffect : public GrEffect {
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...
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virtual const GrBackendEffectFactory& getFactory() const SK_OVERRIDE {
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return GrTBackendEffectFactory<MyCustomEffect>::getInstance();
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}
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...
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};
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*/
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virtual const GrBackendEffectFactory& getFactory() const = 0;
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/** Returns true if the other effect will generate identical output.
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Must only be called if the two are already known to be of the
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same type (i.e. they return the same value from getFactory()).
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Equality is not the same thing as equivalence.
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To test for equivalence (that they will generate the same
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shader code, but may have different uniforms), check equality
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of the EffectKey produced by the GrBackendEffectFactory:
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a.getFactory().glEffectKey(a) == b.getFactory().glEffectKey(b).
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The default implementation of this function returns true iff
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the two stages have the same return value for numTextures() and
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for texture() over all valid indices.
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*/
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virtual bool isEqual(const GrEffect&) const;
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/** Human-meaningful string to identify this effect; may be embedded
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in generated shader code. */
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const char* name() const;
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int numTextures() const { return fNumTextures; }
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/** Returns the access pattern for the texture at index. index must be valid according to
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numTextures(). */
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virtual const GrTextureAccess& textureAccess(int index) const;
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/** Shortcut for textureAccess(index).texture(); */
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GrTexture* texture(int index) const { return this->textureAccess(index).getTexture(); }
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void* operator new(size_t size);
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void operator delete(void* target);
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private:
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int fNumTextures;
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typedef GrRefCnt INHERITED;
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};
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#endif
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