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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 GrGLCustomStage_DEFINED
#define GrGLCustomStage_DEFINED
#include "GrAllocator.h"
#include "GrCustomStage.h"
#include "GrGLProgram.h"
#include "GrGLShaderBuilder.h"
#include "GrGLShaderVar.h"
#include "GrGLSL.h"
struct GrGLInterface;
class GrGLTexture;
/** @file
This file contains specializations for OpenGL of the shader stages declared in
include/gpu/GrCustomStage.h. Objects of type GrGLProgramStage are responsible for emitting the
GLSL code that implements a GrCustomStage and for uploading uniforms at draw time. They also
must have a function:
static inline StageKey GenKey(const GrCustomStage&, const GrGLCaps&)
that is used to implement a program cache. When two GrCustomStages produce the same key this
means that their GrGLProgramStages would emit the same GLSL code.
These objects are created by the factory object returned by the GrCustomStage::getFactory().
*/
class GrGLProgramStage {
public:
typedef GrCustomStage::StageKey StageKey;
enum {
// the number of bits in StageKey available to GenKey
kProgramStageKeyBits = GrProgramStageFactory::kProgramStageKeyBits,
};
typedef GrGLShaderBuilder::TextureSamplerArray TextureSamplerArray;
GrGLProgramStage(const GrProgramStageFactory&);
virtual ~GrGLProgramStage();
/** 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 custom stage that generated this program stage.
@param key The key that was computed by StageKey() from the generating
GrCustomStage.
@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 custom stage to communicate back similar known info about its
output.
@param samplers One entry for each GrTextureAccess of the GrCustomStage that generated
the GrGLProgramStage. These can be passed to the builder to emit texture
reads in the generated code.
*/
virtual void emitCode(GrGLShaderBuilder* builder,
const GrCustomStage& stage,
StageKey key,
const char* vertexCoords,
const char* outputColor,
const char* inputColor,
const TextureSamplerArray& samplers) = 0;
/** A GrGLProgramStage instance can be reused with any GrCustomStage 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(). */
virtual void setData(const GrGLUniformManager&, const GrCustomStage& stage);
const char* name() const { return fFactory.name(); }
static StageKey GenTextureKey(const GrCustomStage&, const GrGLCaps&);
protected:
const GrProgramStageFactory& fFactory;
};
/**
* This allows program stages that implemented an older set of virtual functions on GrGLProgramStage
* to continue to work by change their parent class to this class. New program stages should not use
* this interface. It will be removed once older stages are modified to implement emitCode().
*/
class GrGLLegacyProgramStage : public GrGLProgramStage {
public:
GrGLLegacyProgramStage(const GrProgramStageFactory& factory) : GrGLProgramStage(factory) {}
virtual void setupVariables(GrGLShaderBuilder* builder) {};
virtual void emitVS(GrGLShaderBuilder* builder,
const char* vertexCoords) = 0;
virtual void emitFS(GrGLShaderBuilder* builder,
const char* outputColor,
const char* inputColor,
const TextureSamplerArray&) = 0;
virtual void emitCode(GrGLShaderBuilder* builder,
const GrCustomStage&,
StageKey,
const char* vertexCoords,
const char* outputColor,
const char* inputColor,
const TextureSamplerArray& samplers) {
this->setupVariables(builder);
this->emitVS(builder, vertexCoords);
this->emitFS(builder, outputColor, inputColor, samplers);
}
};
#endif
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