SkiaShader.h revision e3095e0c1e2a4a4f34f741aa386eae56536ca5aa 
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    virtual void setMatrix(SkMatrix* matrix) {
81        mMatrix = matrix;
82    }
83
84protected:
85    inline void bindTexture(GLuint texture, GLenum wrapS, GLenum wrapT, GLuint textureUnit);
86
87    Type mType;
88    SkShader* mKey;
89    SkShader::TileMode mTileX;
90    SkShader::TileMode mTileY;
91    SkMatrix* mMatrix;
92    bool mBlend;
93
94    TextureCache* mTextureCache;
95    GradientCache* mGradientCache;
96}; // struct SkiaShader
97
98
99///////////////////////////////////////////////////////////////////////////////
100// Implementations
101///////////////////////////////////////////////////////////////////////////////
102
103/**
104 * A shader that draws a bitmap.
105 */
106struct SkiaBitmapShader: public SkiaShader {
107    SkiaBitmapShader(SkBitmap* bitmap, SkShader* key, SkShader::TileMode tileX,
108            SkShader::TileMode tileY, SkMatrix* matrix, bool blend);
109
110    void describe(ProgramDescription& description, const Extensions& extensions);
111    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
112            GLuint* textureUnit);
113    void updateTransforms(Program* program, const mat4& modelView, const Snapshot& snapshot);
114
115private:
116    /**
117     * This method does not work for n == 0.
118     */
119    inline bool isPowerOfTwo(unsigned int n) {
120        return !(n & (n - 1));
121    }
122
123    SkBitmap* mBitmap;
124    const Texture* mTexture;
125    GLenum mWrapS;
126    GLenum mWrapT;
127}; // struct SkiaBitmapShader
128
129/**
130 * A shader that draws a linear gradient.
131 */
132struct SkiaLinearGradientShader: public SkiaShader {
133    SkiaLinearGradientShader(float* bounds, uint32_t* colors, float* positions, int count,
134            SkShader* key, SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
135    ~SkiaLinearGradientShader();
136
137    void describe(ProgramDescription& description, const Extensions& extensions);
138    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
139            GLuint* textureUnit);
140    void updateTransforms(Program* program, const mat4& modelView, const Snapshot& snapshot);
141
142    void setMatrix(SkMatrix* matrix);
143
144private:
145    void updateLocalMatrix(const SkMatrix* matrix);
146    void computeScreenSpaceMatrix(mat4& screenSpace, const mat4& modelView);
147
148    mat4 mUnitMatrix;
149    mat4 mShaderMatrix;
150
151    float* mBounds;
152    uint32_t* mColors;
153    float* mPositions;
154    int mCount;
155}; // struct SkiaLinearGradientShader
156
157/**
158 * A shader that draws a sweep gradient.
159 */
160struct SkiaSweepGradientShader: public SkiaShader {
161    SkiaSweepGradientShader(float x, float y, uint32_t* colors, float* positions, int count,
162            SkShader* key, SkMatrix* matrix, bool blend);
163    ~SkiaSweepGradientShader();
164
165    virtual void describe(ProgramDescription& description, const Extensions& extensions);
166    virtual void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
167            GLuint* textureUnit);
168    void updateTransforms(Program* program, const mat4& modelView, const Snapshot& snapshot);
169
170protected:
171    SkiaSweepGradientShader(Type type, float x, float y, uint32_t* colors, float* positions,
172            int count, SkShader* key, SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
173
174    float mX, mY;
175    uint32_t* mColors;
176    float* mPositions;
177    int mCount;
178}; // struct SkiaSweepGradientShader
179
180/**
181 * A shader that draws a circular gradient.
182 */
183struct SkiaCircularGradientShader: public SkiaSweepGradientShader {
184    SkiaCircularGradientShader(float x, float y, float radius, uint32_t* colors, float* positions,
185            int count, SkShader* key,SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
186
187    void describe(ProgramDescription& description, const Extensions& extensions);
188    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
189            GLuint* textureUnit);
190
191private:
192    float mRadius;
193}; // struct SkiaCircularGradientShader
194
195/**
196 * A shader that draws two shaders, composited with an xfermode.
197 */
198struct SkiaComposeShader: public SkiaShader {
199    SkiaComposeShader(SkiaShader* first, SkiaShader* second, SkXfermode::Mode mode, SkShader* key);
200
201    void set(TextureCache* textureCache, GradientCache* gradientCache);
202
203    void describe(ProgramDescription& description, const Extensions& extensions);
204    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
205            GLuint* textureUnit);
206
207private:
208    SkiaShader* mFirst;
209    SkiaShader* mSecond;
210    SkXfermode::Mode mMode;
211}; // struct SkiaComposeShader
212
213}; // namespace uirenderer
214}; // namespace android
215
216#endif // ANDROID_UI_SKIA_SHADER_H
217