SkiaShader.h revision 01d065795794fa56be660d6346e4830eb7e90a41 
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_HWUI_SKIA_SHADER_H
18#define ANDROID_HWUI_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 SkShader *getSkShader() {
64        return mKey;
65    }
66
67    inline bool blend() const {
68        return mBlend;
69    }
70
71    Type type() const {
72        return mType;
73    }
74
75    virtual void set(TextureCache* textureCache, GradientCache* gradientCache) {
76        mTextureCache = textureCache;
77        mGradientCache = gradientCache;
78    }
79
80    virtual void updateTransforms(Program* program, const mat4& modelView,
81            const Snapshot& snapshot) {
82    }
83
84    void setMatrix(SkMatrix* matrix) {
85        updateLocalMatrix(matrix);
86    }
87
88    void updateLocalMatrix(const SkMatrix* matrix) {
89        if (matrix) {
90            mat4 localMatrix(*matrix);
91            mShaderMatrix.loadInverse(localMatrix);
92        } else {
93            mShaderMatrix.loadIdentity();
94        }
95    }
96
97    void computeScreenSpaceMatrix(mat4& screenSpace, const mat4& modelView);
98
99protected:
100    /**
101     * The appropriate texture unit must have been activated prior to invoking
102     * this method.
103     */
104    inline void bindTexture(Texture* texture, GLenum wrapS, GLenum wrapT);
105
106    Type mType;
107    SkShader* mKey;
108    SkShader::TileMode mTileX;
109    SkShader::TileMode mTileY;
110    bool mBlend;
111
112    TextureCache* mTextureCache;
113    GradientCache* mGradientCache;
114
115    mat4 mUnitMatrix;
116    mat4 mShaderMatrix;
117}; // struct SkiaShader
118
119
120///////////////////////////////////////////////////////////////////////////////
121// Implementations
122///////////////////////////////////////////////////////////////////////////////
123
124/**
125 * A shader that draws a bitmap.
126 */
127struct SkiaBitmapShader: public SkiaShader {
128    SkiaBitmapShader(SkBitmap* bitmap, SkShader* key, SkShader::TileMode tileX,
129            SkShader::TileMode tileY, SkMatrix* matrix, bool blend);
130
131    void describe(ProgramDescription& description, const Extensions& extensions);
132    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
133            GLuint* textureUnit);
134    void updateTransforms(Program* program, const mat4& modelView, const Snapshot& snapshot);
135
136private:
137    /**
138     * This method does not work for n == 0.
139     */
140    inline bool isPowerOfTwo(unsigned int n) {
141        return !(n & (n - 1));
142    }
143
144    SkBitmap* mBitmap;
145    Texture* mTexture;
146    GLenum mWrapS;
147    GLenum mWrapT;
148}; // struct SkiaBitmapShader
149
150/**
151 * A shader that draws a linear gradient.
152 */
153struct SkiaLinearGradientShader: public SkiaShader {
154    SkiaLinearGradientShader(float* bounds, uint32_t* colors, float* positions, int count,
155            SkShader* key, SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
156    ~SkiaLinearGradientShader();
157
158    void describe(ProgramDescription& description, const Extensions& extensions);
159    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
160            GLuint* textureUnit);
161    void updateTransforms(Program* program, const mat4& modelView, const Snapshot& snapshot);
162
163private:
164    float* mBounds;
165    uint32_t* mColors;
166    float* mPositions;
167    int mCount;
168}; // struct SkiaLinearGradientShader
169
170/**
171 * A shader that draws a sweep gradient.
172 */
173struct SkiaSweepGradientShader: public SkiaShader {
174    SkiaSweepGradientShader(float x, float y, uint32_t* colors, float* positions, int count,
175            SkShader* key, SkMatrix* matrix, bool blend);
176    ~SkiaSweepGradientShader();
177
178    virtual void describe(ProgramDescription& description, const Extensions& extensions);
179    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
180            GLuint* textureUnit);
181    void updateTransforms(Program* program, const mat4& modelView, const Snapshot& snapshot);
182
183protected:
184    SkiaSweepGradientShader(Type type, float x, float y, uint32_t* colors, float* positions,
185            int count, SkShader* key, SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
186
187    uint32_t* mColors;
188    float* mPositions;
189    int mCount;
190}; // struct SkiaSweepGradientShader
191
192/**
193 * A shader that draws a circular gradient.
194 */
195struct SkiaCircularGradientShader: public SkiaSweepGradientShader {
196    SkiaCircularGradientShader(float x, float y, float radius, uint32_t* colors, float* positions,
197            int count, SkShader* key,SkShader::TileMode tileMode, SkMatrix* matrix, bool blend);
198
199    void describe(ProgramDescription& description, const Extensions& extensions);
200}; // struct SkiaCircularGradientShader
201
202/**
203 * A shader that draws two shaders, composited with an xfermode.
204 */
205struct SkiaComposeShader: public SkiaShader {
206    SkiaComposeShader(SkiaShader* first, SkiaShader* second, SkXfermode::Mode mode, SkShader* key);
207
208    void set(TextureCache* textureCache, GradientCache* gradientCache);
209
210    void describe(ProgramDescription& description, const Extensions& extensions);
211    void setupProgram(Program* program, const mat4& modelView, const Snapshot& snapshot,
212            GLuint* textureUnit);
213
214private:
215    SkiaShader* mFirst;
216    SkiaShader* mSecond;
217    SkXfermode::Mode mMode;
218}; // struct SkiaComposeShader
219
220}; // namespace uirenderer
221}; // namespace android
222
223#endif // ANDROID_HWUI_SKIA_SHADER_H
224