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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 GrGLEffectMatrix_DEFINED
#define GrGLEffectMatrix_DEFINED
#include "GrGLEffect.h"
#include "SkMatrix.h"
class GrTexture;
/**
* This is a helper to implement a texture matrix in a GrGLEffect.
*/
class GrGLEffectMatrix {
public:
typedef GrGLEffect::EffectKey EffectKey;
/**
* The matrix uses kKeyBits of the effect's EffectKey. A GrGLEffect may place these bits at an
* arbitrary shift in its final key. However, when GrGLEffectMatrix::emitCode*() code is called
* the relevant bits must be in the lower kKeyBits of the key parameter.
*/
enum {
kKeyBits = 2,
kKeyMask = (1 << kKeyBits) - 1,
};
GrGLEffectMatrix() : fUni(GrGLUniformManager::kInvalidUniformHandle) {
fPrevMatrix = SkMatrix::InvalidMatrix();
}
/**
* Generates the key for the portion of the code emitted by this class's emitCode() function.
* Pass a texture to make GrGLEffectMatrix automatically adjust for the texture's origin. Pass
* NULL when not using the EffectMatrix for a texture lookups, or if the GrGLEffect subclass
* wants to handle origin adjustments in some other manner. coordChangeMatrix is the matrix
* from GrEffectStage.
*/
static EffectKey GenKey(const SkMatrix& effectMatrix,
const SkMatrix& coordChangeMatrix,
const GrTexture*);
/**
* Emits code to implement the matrix in the VS. A varying is added as an output of the VS and
* input to the FS. The varying may be either a vec2f or vec3f depending upon whether
* perspective interpolation is required or not. The names of the varying in the VS and FS are
* are returned as output parameters and the type of the varying is the return value. The suffix
* is an optional parameter that can be used to make all variables emitted by the object
* unique within a stage. It is only necessary if multiple GrGLEffectMatrix objects are used by
* a GrGLEffect.
*/
GrSLType emitCode(GrGLShaderBuilder*,
EffectKey,
const char* vertexCoords,
const char** fsCoordName, /* optional */
const char** vsCoordName = NULL,
const char* suffix = NULL);
/**
* This is similar to emitCode except that it performs perspective division in the FS if the
* texture coordinates have a w coordinate. The fsCoordName always refers to a vec2f.
*/
void emitCodeMakeFSCoords2D(GrGLShaderBuilder*,
EffectKey,
const char* vertexCoords,
const char** fsCoordName, /* optional */
const char** vsVaryingName = NULL,
GrSLType* vsVaryingType = NULL,
const char* suffix = NULL);
/**
* Call from a GrGLEffect's subclass to update the texture matrix. The matrix,
* coordChangeMatrix, and texture params should match those used with GenKey.
*/
void setData(const GrGLUniformManager& uniformManager,
const SkMatrix& effectMatrix,
const SkMatrix& coordChangeMatrix,
const GrTexture*);
private:
enum {
kIdentity_Key = 0,
kTrans_Key = 1,
kNoPersp_Key = 2,
kGeneral_Key = 3,
};
GrGLUniformManager::UniformHandle fUni;
GrSLType fUniType;
SkMatrix fPrevMatrix;
};
#endif
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