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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 GrGLShaderBuilder_DEFINED
#define GrGLShaderBuilder_DEFINED
#include "GrAllocator.h"
#include "GrCustomStage.h"
#include "gl/GrGLShaderVar.h"
#include "gl/GrGLSL.h"
#include "gl/GrGLUniformManager.h"
class GrGLContextInfo;
/**
Contains all the incremental state of a shader as it is being built,as well as helpers to
manipulate that state.
*/
class GrGLShaderBuilder {
public:
enum ShaderType {
kVertex_ShaderType = 0x1,
kGeometry_ShaderType = 0x2,
kFragment_ShaderType = 0x4,
};
GrGLShaderBuilder(const GrGLContextInfo&, GrGLUniformManager&);
void computeSwizzle(uint32_t configFlags);
void computeModulate(const char* fsInColor);
// TODO: needs a better name
enum SamplerMode {
kDefault_SamplerMode,
kProj_SamplerMode,
kExplicitDivide_SamplerMode // must do an explicit divide
};
/** Determines whether we should use texture2D() or texture2Dproj(), and if an explicit divide
is required for the sample coordinates, creates the new variable and emits the code to
initialize it. */
void setupTextureAccess(int stageNum);
/** texture2D(samplerName, coordName), with projection if necessary; if coordName is not
specified, uses fSampleCoords. */
void emitTextureLookup(const char* samplerName,
const char* coordName = NULL);
/** sets outColor to results of texture lookup, with swizzle, and/or modulate as necessary */
void emitDefaultFetch(const char* outColor,
const char* samplerName);
/** Emits a texture lookup to the shader code with the form:
texture2D{Proj}(samplerName, coordName).swizzle
The routine selects the type of texturing based on samplerMode.
The generated swizzle state is built based on the format of the texture and the requested
swizzle access pattern. */
void emitCustomTextureLookup(SamplerMode samplerMode,
const GrTextureAccess& textureAccess,
const char* samplerName,
const char* coordName);
/** Emits a helper function outside of main(). Currently ShaderType must be
kFragment_ShaderType. */
void emitFunction(ShaderType shader,
GrSLType returnType,
const char* name,
int argCnt,
const GrGLShaderVar* args,
const char* body,
SkString* outName);
/** Generates a StageKey for the shader code based on the texture access parameters and the
capabilities of the GL context. This is useful for keying the shader programs that may
have multiple representations, based on the type/format of textures used. */
static GrCustomStage::StageKey KeyForTextureAccess(const GrTextureAccess& access,
const GrGLCaps& caps);
/** Add a uniform variable to the current program, that has visibilty in one or more shaders.
visibility is a bitfield of ShaderType values indicating from which shaders the uniform
should be accessible. At least one bit must be set. Geometry shader uniforms are not
supported at this time. The actual uniform name will be mangled. If outName is not NULL then
it will refer to the final uniform name after return. Use the addUniformArray variant to add
an array of uniforms.
*/
GrGLUniformManager::UniformHandle addUniform(uint32_t visibility,
GrSLType type,
const char* name,
const char** outName = NULL) {
return this->addUniformArray(visibility, type, name, GrGLShaderVar::kNonArray, outName);
}
GrGLUniformManager::UniformHandle addUniformArray(uint32_t visibility,
GrSLType type,
const char* name,
int arrayCount,
const char** outName = NULL);
const GrGLShaderVar& getUniformVariable(GrGLUniformManager::UniformHandle) const;
/**
* Shorcut for getUniformVariable(u).c_str()
*/
const char* getUniformCStr(GrGLUniformManager::UniformHandle u) const {
return this->getUniformVariable(u).c_str();
}
/** Add a varying variable to the current program to pass values between vertex and fragment
shaders. If the last two parameters are non-NULL, they are filled in with the name
generated. */
void addVarying(GrSLType type,
const char* name,
const char** vsOutName = NULL,
const char** fsInName = NULL);
/** Called after building is complete to get the final shader string. */
void getShader(ShaderType, SkString*) const;
/**
* TODO: Make this do all the compiling, linking, etc. Hide from the custom stages
*/
void finished(GrGLuint programID);
/**
* Sets the current stage (used to make variable names unique).
* TODO: Hide from the custom stages
*/
void setCurrentStage(int stage) { fCurrentStage = stage; }
void setNonStage() { fCurrentStage = kNonStageIdx; }
private:
typedef GrTAllocator<GrGLShaderVar> VarArray;
void appendDecls(const VarArray&, SkString*) const;
void appendUniformDecls(ShaderType, SkString*) const;
typedef GrGLUniformManager::BuilderUniform BuilderUniform;
GrGLUniformManager::BuilderUniformArray fUniforms;
// TODO: Everything below here private.
public:
SkString fHeader; // VS+FS, GLSL version, etc
VarArray fVSAttrs;
VarArray fVSOutputs;
VarArray fGSInputs;
VarArray fGSOutputs;
VarArray fFSInputs;
SkString fGSHeader; // layout qualifiers specific to GS
VarArray fFSOutputs;
SkString fVSCode;
SkString fGSCode;
SkString fFSCode;
bool fUsesGS;
/// Per-stage settings - only valid while we're inside GrGLProgram::genStageCode().
//@{
int fVaryingDims;
static const int fCoordDims = 2;
/// True if fSampleCoords is an expression; false if it's a bare
/// variable name
bool fComplexCoord;
SkString fSampleCoords;
SkString fSwizzle;
SkString fModulate;
SkString fTexFunc;
//@}
private:
enum {
kNonStageIdx = -1,
};
const GrGLContextInfo& fContext;
GrGLUniformManager& fUniformManager;
int fCurrentStage;
SkString fFSFunctions;
};
#endif
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