SkiaShader.h revision 14830948d02f768c41b97b7a8d15e1b3cab78267 
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    virtual void updateTransforms(Program* program, const mat4& modelView,
77            const Snapshot& snapshot) {
78    }
79
80    void setMatrix(SkMatrix* matrix) {
81        updateLocalMatrix(matrix);
82    }
83
84    void updateLocalMatrix(const SkMatrix* matrix) {
85        if (matrix) {
86            mat4 localMatrix(*matrix);
87            mShaderMatrix.loadInverse(localMatrix);
88        } else {
89            mShaderMatrix.loadIdentity();
90        }
91    }
92
93    void computeScreenSpaceMatrix(mat4& screenSpace, const mat4& modelView);
94
95protected:
96    inline void bindTexture(GLuint texture, GLenum wrapS, GLenum wrapT, GLuint textureUnit);
97
98    Type mType;
99    SkShader* mKey;
100    SkShader::TileMode mTileX;
101    SkShader::TileMode mTileY;
102    bool mBlend;
103
104    TextureCache* mTextureCache;
105    GradientCache* mGradientCache;
106
107    mat4 mUnitMatrix;
108    mat4 mShaderMatrix;
109}; // struct SkiaShader
110
111
112///////////////////////////////////////////////////////////////////////////////
113// Implementations
114///////////////////////////////////////////////////////////////////////////////
115
116/**
117 * A shader that draws a bitmap.
118 */
119struct SkiaBitmapShader: public SkiaShader {
120    SkiaBitmapShader(SkBitmap* bitmap, SkShader* key, SkShader::TileMode tileX,
121            SkShader::TileMode tileY, SkMatrix* matrix, bool blend);
122
123    void describe(ProgramDescription& description, const Extensions& extensions);
124    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
125            GLuint* textureUnit);
126    void updateTransforms(Program* program, const mat4& modelView, const Snapshot& snapshot);
127
128private:
129    /**
130     * This method does not work for n == 0.
131     */
132    inline bool isPowerOfTwo(unsigned int n) {
133        return !(n & (n - 1));
134    }
135
136    SkBitmap* mBitmap;
137    const Texture* mTexture;
138    GLenum mWrapS;
139    GLenum mWrapT;
140}; // struct SkiaBitmapShader
141
142/**
143 * A shader that draws a linear gradient.
144 */
145struct SkiaLinearGradientShader: public SkiaShader {
146    SkiaLinearGradientShader(float* bounds, uint32_t* colors, float* positions, int count,
147            SkShader* key, SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
148    ~SkiaLinearGradientShader();
149
150    void describe(ProgramDescription& description, const Extensions& extensions);
151    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
152            GLuint* textureUnit);
153    void updateTransforms(Program* program, const mat4& modelView, const Snapshot& snapshot);
154
155private:
156    float* mBounds;
157    uint32_t* mColors;
158    float* mPositions;
159    int mCount;
160}; // struct SkiaLinearGradientShader
161
162/**
163 * A shader that draws a sweep gradient.
164 */
165struct SkiaSweepGradientShader: public SkiaShader {
166    SkiaSweepGradientShader(float x, float y, uint32_t* colors, float* positions, int count,
167            SkShader* key, SkMatrix* matrix, bool blend);
168    ~SkiaSweepGradientShader();
169
170    virtual void describe(ProgramDescription& description, const Extensions& extensions);
171    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
172            GLuint* textureUnit);
173    void updateTransforms(Program* program, const mat4& modelView, const Snapshot& snapshot);
174
175protected:
176    SkiaSweepGradientShader(Type type, float x, float y, uint32_t* colors, float* positions,
177            int count, SkShader* key, SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
178
179    uint32_t* mColors;
180    float* mPositions;
181    int mCount;
182}; // struct SkiaSweepGradientShader
183
184/**
185 * A shader that draws a circular gradient.
186 */
187struct SkiaCircularGradientShader: public SkiaSweepGradientShader {
188    SkiaCircularGradientShader(float x, float y, float radius, uint32_t* colors, float* positions,
189            int count, SkShader* key,SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
190
191    void describe(ProgramDescription& description, const Extensions& extensions);
192}; // struct SkiaCircularGradientShader
193
194/**
195 * A shader that draws two shaders, composited with an xfermode.
196 */
197struct SkiaComposeShader: public SkiaShader {
198    SkiaComposeShader(SkiaShader* first, SkiaShader* second, SkXfermode::Mode mode, SkShader* key);
199
200    void set(TextureCache* textureCache, GradientCache* gradientCache);
201
202    void describe(ProgramDescription& description, const Extensions& extensions);
203    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
204            GLuint* textureUnit);
205
206private:
207    SkiaShader* mFirst;
208    SkiaShader* mSecond;
209    SkXfermode::Mode mMode;
210}; // struct SkiaComposeShader
211
212}; // namespace uirenderer
213}; // namespace android
214
215#endif // ANDROID_UI_SKIA_SHADER_H
216