SkiaShader.h revision 6c07daf86c0d3824e1cd88fea455e2dd7b88cbcd 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef ANDROID_UI_SKIA_SHADER_H
18#define ANDROID_UI_SKIA_SHADER_H
19
20#include <SkShader.h>
21#include <SkXfermode.h>
22
23#include <GLES2/gl2.h>
24
25#include "Extensions.h"
26#include "ProgramCache.h"
27#include "TextureCache.h"
28#include "GradientCache.h"
29#include "Snapshot.h"
30
31namespace android {
32namespace uirenderer {
33
34///////////////////////////////////////////////////////////////////////////////
35// Base shader
36///////////////////////////////////////////////////////////////////////////////
37
38/**
39 * Represents a Skia shader. A shader will modify the GL context and active
40 * program to recreate the original effect.
41 */
42struct SkiaShader {
43    /**
44     * Type of Skia shader in use.
45     */
46    enum Type {
47        kNone,
48        kBitmap,
49        kLinearGradient,
50        kCircularGradient,
51        kSweepGradient,
52        kCompose
53    };
54
55    SkiaShader(Type type, SkShader* key, SkShader::TileMode tileX, SkShader::TileMode tileY,
56            SkMatrix* matrix, bool blend);
57    virtual ~SkiaShader();
58
59    virtual void describe(ProgramDescription& description, const Extensions& extensions);
60    virtual void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
61            GLuint* textureUnit);
62
63    inline bool blend() const {
64        return mBlend;
65    }
66
67    Type type() const {
68        return mType;
69    }
70
71    virtual void set(TextureCache* textureCache, GradientCache* gradientCache) {
72        mTextureCache = textureCache;
73        mGradientCache = gradientCache;
74    }
75
76    void setMatrix(SkMatrix* matrix) {
77        mMatrix = matrix;
78    }
79
80protected:
81    inline void bindTexture(GLuint texture, GLenum wrapS, GLenum wrapT, GLuint textureUnit);
82
83    Type mType;
84    SkShader* mKey;
85    SkShader::TileMode mTileX;
86    SkShader::TileMode mTileY;
87    SkMatrix* mMatrix;
88    bool mBlend;
89
90    TextureCache* mTextureCache;
91    GradientCache* mGradientCache;
92}; // struct SkiaShader
93
94
95///////////////////////////////////////////////////////////////////////////////
96// Implementations
97///////////////////////////////////////////////////////////////////////////////
98
99/**
100 * A shader that draws a bitmap.
101 */
102struct SkiaBitmapShader: public SkiaShader {
103    SkiaBitmapShader(SkBitmap* bitmap, SkShader* key, SkShader::TileMode tileX,
104            SkShader::TileMode tileY, SkMatrix* matrix, bool blend);
105
106    void describe(ProgramDescription& description, const Extensions& extensions);
107    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
108            GLuint* textureUnit);
109
110private:
111    /**
112     * This method does not work for n == 0.
113     */
114    inline bool isPowerOfTwo(unsigned int n) {
115        return !(n & (n - 1));
116    }
117
118    SkBitmap* mBitmap;
119}; // struct SkiaBitmapShader
120
121/**
122 * A shader that draws a linear gradient.
123 */
124struct SkiaLinearGradientShader: public SkiaShader {
125    SkiaLinearGradientShader(float* bounds, uint32_t* colors, float* positions, int count,
126            SkShader* key, SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
127    ~SkiaLinearGradientShader();
128
129    void describe(ProgramDescription& description, const Extensions& extensions);
130    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
131            GLuint* textureUnit);
132
133private:
134    float* mBounds;
135    uint32_t* mColors;
136    float* mPositions;
137    int mCount;
138}; // struct SkiaLinearGradientShader
139
140/**
141 * A shader that draws two shaders, composited with an xfermode.
142 */
143struct SkiaComposeShader: public SkiaShader {
144    SkiaComposeShader(SkiaShader* first, SkiaShader* second, SkXfermode::Mode mode, SkShader* key);
145
146    void set(TextureCache* textureCache, GradientCache* gradientCache);
147
148    void describe(ProgramDescription& description, const Extensions& extensions);
149    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
150            GLuint* textureUnit);
151
152private:
153    SkiaShader* mFirst;
154    SkiaShader* mSecond;
155    SkXfermode::Mode mMode;
156}; // struct SkiaComposeShader
157
158}; // namespace uirenderer
159}; // namespace android
160
161#endif // ANDROID_UI_SKIA_SHADER_H
162