1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/src/gpu/gl/GrGLEffect.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,113 @@
1.4 +/*
1.5 + * Copyright 2012 Google Inc.
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef GrGLEffect_DEFINED
1.12 +#define GrGLEffect_DEFINED
1.13 +
1.14 +#include "GrBackendEffectFactory.h"
1.15 +#include "GrGLProgramEffects.h"
1.16 +#include "GrGLShaderBuilder.h"
1.17 +#include "GrGLShaderVar.h"
1.18 +#include "GrGLSL.h"
1.19 +
1.20 +/** @file
1.21 + This file contains specializations for OpenGL of the shader stages declared in
1.22 + include/gpu/GrEffect.h. Objects of type GrGLEffect are responsible for emitting the
1.23 + GLSL code that implements a GrEffect and for uploading uniforms at draw time. If they don't
1.24 + always emit the same GLSL code, they must have a function:
1.25 + static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&)
1.26 + that is used to implement a program cache. When two GrEffects produce the same key this means
1.27 + that their GrGLEffects would emit the same GLSL code.
1.28 +
1.29 + The GrGLEffect subclass must also have a constructor of the form:
1.30 + EffectSubclass::EffectSubclass(const GrBackendEffectFactory&, const GrDrawEffect&)
1.31 + The effect held by the GrDrawEffect is guaranteed to be of the type that generated the
1.32 + GrGLEffect subclass instance.
1.33 +
1.34 + These objects are created by the factory object returned by the GrEffect::getFactory().
1.35 +*/
1.36 +
1.37 +class GrDrawEffect;
1.38 +class GrGLTexture;
1.39 +class GrGLVertexEffect;
1.40 +
1.41 +class GrGLEffect {
1.42 +
1.43 +public:
1.44 + typedef GrBackendEffectFactory::EffectKey EffectKey;
1.45 + typedef GrGLProgramEffects::TransformedCoordsArray TransformedCoordsArray;
1.46 + typedef GrGLProgramEffects::TextureSampler TextureSampler;
1.47 + typedef GrGLProgramEffects::TextureSamplerArray TextureSamplerArray;
1.48 +
1.49 + enum {
1.50 + kNoEffectKey = GrBackendEffectFactory::kNoEffectKey,
1.51 + // the number of bits in EffectKey available to GenKey
1.52 + kEffectKeyBits = GrBackendEffectFactory::kEffectKeyBits,
1.53 + };
1.54 +
1.55 + GrGLEffect(const GrBackendEffectFactory& factory)
1.56 + : fFactory(factory)
1.57 + , fIsVertexEffect(false) {
1.58 + }
1.59 +
1.60 + virtual ~GrGLEffect() {}
1.61 +
1.62 + /** Called when the program stage should insert its code into the shaders. The code in each
1.63 + shader will be in its own block ({}) and so locally scoped names will not collide across
1.64 + stages.
1.65 +
1.66 + @param builder Interface used to emit code in the shaders.
1.67 + @param drawEffect A wrapper on the effect that generated this program stage.
1.68 + @param key The key that was computed by GenKey() from the generating GrEffect.
1.69 + Only the bits indicated by GrBackendEffectFactory::kEffectKeyBits are
1.70 + guaranteed to match the value produced by GenKey();
1.71 + @param outputColor A predefined vec4 in the FS in which the stage should place its output
1.72 + color (or coverage).
1.73 + @param inputColor A vec4 that holds the input color to the stage in the FS. This may be
1.74 + NULL in which case the implied input is solid white (all ones).
1.75 + TODO: Better system for communicating optimization info (e.g. input
1.76 + color is solid white, trans black, known to be opaque, etc.) that allows
1.77 + the effect to communicate back similar known info about its output.
1.78 + @param samplers One entry for each GrTextureAccess of the GrEffect that generated the
1.79 + GrGLEffect. These can be passed to the builder to emit texture
1.80 + reads in the generated code.
1.81 + */
1.82 + virtual void emitCode(GrGLShaderBuilder* builder,
1.83 + const GrDrawEffect& drawEffect,
1.84 + EffectKey key,
1.85 + const char* outputColor,
1.86 + const char* inputColor,
1.87 + const TransformedCoordsArray& coords,
1.88 + const TextureSamplerArray& samplers) = 0;
1.89 +
1.90 + /** A GrGLEffect instance can be reused with any GrEffect that produces the same stage
1.91 + key; this function reads data from a stage and uploads any uniform variables required
1.92 + by the shaders created in emitCode(). The GrEffect installed in the GrEffectStage is
1.93 + guaranteed to be of the same type that created this GrGLEffect and to have an identical
1.94 + EffectKey as the one that created this GrGLEffect. Effects that use local coords have
1.95 + to consider whether the GrEffectStage's coord change matrix should be used. When explicit
1.96 + local coordinates are used it can be ignored. */
1.97 + virtual void setData(const GrGLUniformManager&, const GrDrawEffect&) {}
1.98 +
1.99 + const char* name() const { return fFactory.name(); }
1.100 +
1.101 + static inline EffectKey GenKey(const GrDrawEffect&, const GrGLCaps&) { return 0; }
1.102 +
1.103 + /** Used by the system when generating shader code, to see if this effect can be downcasted to
1.104 + the internal GrGLVertexEffect type */
1.105 + bool isVertexEffect() const { return fIsVertexEffect; }
1.106 +
1.107 +protected:
1.108 + const GrBackendEffectFactory& fFactory;
1.109 +
1.110 +private:
1.111 + friend class GrGLVertexEffect; // to set fIsVertexEffect
1.112 +
1.113 + bool fIsVertexEffect;
1.114 +};
1.115 +
1.116 +#endif
