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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 src/gpu/GrCustomStage.h. All the functions emit
GLSL shader code and OpenGL calls.
These objects are created by a factory function on the
GrCustomStage.
TODO: lifetime management.
*/
class GrGLProgramStage {
public:
typedef GrCustomStage::StageKey StageKey;
enum {
// the number of bits in StageKey available to GenKey
kProgramStageKeyBits = GrProgramStageFactory::kProgramStageKeyBits,
};
GrGLProgramStage(const GrProgramStageFactory&);
virtual ~GrGLProgramStage();
/** Create any uniforms or varyings the vertex shader requires. */
virtual void setupVariables(GrGLShaderBuilder* builder);
/** Appends vertex code to the appropriate SkString
on the state.
The code will be inside an otherwise-empty block.
Vertex shader input is a vec2 of coordinates, which may
be altered.
The code will be inside an otherwise-empty block. */
virtual void emitVS(GrGLShaderBuilder* builder,
const char* vertexCoords) = 0;
/** Appends fragment code to the appropriate SkString
on the state.
The code will be inside an otherwise-empty block.
Fragment shader inputs are a vec2 of coordinates, one texture,
and a color; output is a color. The input color may be NULL which
indicates that the input color is solid white. 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.
*/
/* TODO: don't give them the samplerName, just a handle; then give
a function here for them to call into that'll apply any texture
domain - but do we force them to be honest about texture domain
parameters? */
virtual void emitFS(GrGLShaderBuilder* builder,
const char* outputColor,
const char* inputColor,
const char* samplerName) = 0;
/** A GrGLCustomStage 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 emit*(). */
virtual void setData(const GrGLUniformManager&,
const GrCustomStage& stage,
const GrRenderTarget* renderTarget,
int stageNum);
const char* name() const { return fFactory.name(); }
static StageKey GenTextureKey(const GrCustomStage&, const GrGLCaps&);
protected:
const GrProgramStageFactory& fFactory;
};
#endif
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