GrDrawEffect.h revision c78188896e28a4ae49e406a7422b345ae177dafe 
1
2#ifndef GrDrawEffect_DEFINED
3#define GrDrawEffect_DEFINED
4
5#include "GrEffectStage.h"
6
7/**
8 * This class is used to communicate the particular GrEffect used in a draw to the backend-specific
9 * effect subclass (e.g. GrGLEffect). It is used to by the backend-specific class to generate a
10 * cache key for the effect, generate code on a program cache miss, and to upload uniform values to
11 * the program.
12 * In addition to the effect, it also communicates any changes between the relationship between
13 * the view matrix and local coordinate system since the effect was installed in its GrDrawState.
14 * The typical use case is that sometime after an effect was installed a decision was made to draw
15 * in device coordinates (i.e. use an identity view-matrix). In such a case the GrDrawEffect's
16 * coord-change-matrix would be the inverse of the view matrix that was set when the effect was
17 * installed. GrGLEffectMatrix is a handy class that implements a local coordinate matrix that
18 * automatically accounts for the coord-change matrix.
19 */
20class GrDrawEffect {
21public:
22    GrDrawEffect(const GrEffectStage& stage, bool explicitLocalCoords)
23        : fEffectStage(&stage)
24        , fExplicitLocalCoords(explicitLocalCoords) {
25        GrAssert(NULL != fEffectStage);
26        GrAssert(NULL != fEffectStage->getEffect());
27    }
28    const GrEffectRef* effect() const { return fEffectStage->getEffect(); }
29
30    template <typename T>
31    const T& castEffect() const { return *static_cast<const T*>(this->effect()->get()); }
32
33    const SkMatrix& getCoordChangeMatrix() const {
34        if (fExplicitLocalCoords) {
35            return SkMatrix::I();
36        } else {
37            return fEffectStage->getCoordChangeMatrix();
38        }
39    }
40
41    bool programHasExplicitLocalCoords() const { return fExplicitLocalCoords; }
42
43    const int* getVertexAttribIndices() const { return fEffectStage->getVertexAttribIndices(); }
44    int getVertexAttribIndexCount() const { return fEffectStage->getVertexAttribIndexCount(); }
45
46private:
47    const GrEffectStage*    fEffectStage;
48    bool                    fExplicitLocalCoords;
49};
50
51#endif
52