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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef GrGLEffect_DEFINED
#define GrGLEffect_DEFINED
#include "GrBackendEffectFactory.h"
#include "GrGLProgram.h"
#include "GrGLShaderBuilder.h"
#include "GrGLShaderVar.h"
#include "GrGLSL.h"
class GrEffectStage;
class GrGLTexture;
/** @file
This file contains specializations for OpenGL of the shader stages declared in
include/gpu/GrEffect.h. Objects of type GrGLEffect are responsible for emitting the
GLSL code that implements a GrEffect and for uploading uniforms at draw time. They also
must have a function:
static inline EffectKey GenKey(const GrEffectStage&, const GrGLCaps&)
that is used to implement a program cache. When two GrEffects produce the same key this means
that their GrGLEffects would emit the same GLSL code.
These objects are created by the factory object returned by the GrEffect::getFactory().
*/
class GrGLEffect {
public:
typedef GrBackendEffectFactory::EffectKey EffectKey;
enum {
// the number of bits in EffectKey available to GenKey
kEffectKeyBits = GrBackendEffectFactory::kEffectKeyBits,
};
typedef GrGLShaderBuilder::TextureSamplerArray TextureSamplerArray;
GrGLEffect(const GrBackendEffectFactory&);
virtual ~GrGLEffect();
/** Called when the program stage should insert its code into the shaders. The code in each
shader will be in its own block ({}) and so locally scoped names will not collide across
stages.
@param builder Interface used to emit code in the shaders.
@param stage The effect stage that generated this program stage.
@param key The key that was computed by EffectKey() from the generating GrEffect.
@param vertexCoords A vec2 of texture coordinates in the VS, which may be altered. This will
be removed soon and stages will be responsible for computing their own
coords.
@param outputColor A predefined vec4 in the FS in which the stage should place its output
color (or coverage).
@param inputColor A vec4 that holds the input color to the stage in the FS. This may be
NULL in which case the implied input is solid white (all ones).
TODO: Better system for communicating optimization info (e.g. input
color is solid white, trans black, known to be opaque, etc.) that allows
the effect to communicate back similar known info about its output.
@param samplers One entry for each GrTextureAccess of the GrEffect that generated the
GrGLEffect. These can be passed to the builder to emit texture
reads in the generated code.
*/
virtual void emitCode(GrGLShaderBuilder* builder,
const GrEffectStage& stage,
EffectKey key,
const char* vertexCoords,
const char* outputColor,
const char* inputColor,
const TextureSamplerArray& samplers) = 0;
/** A GrGLEffect instance can be reused with any GrEffect that produces the same stage
key; this function reads data from a stage and uploads any uniform variables required
by the shaders created in emitCode(). The GrEffect installed in the GrEffectStage is
guaranteed to be of the same type that created this GrGLEffect and to have an identical
EffectKey as the one that created this GrGLEffect. */
virtual void setData(const GrGLUniformManager&, const GrEffectStage&);
const char* name() const { return fFactory.name(); }
static EffectKey GenTextureKey(const GrEffect&, const GrGLCaps&);
protected:
const GrBackendEffectFactory& fFactory;
};
#endif
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