1 /*
2  * Copyright (C) 2012 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_DITHER_H
18 #define ANDROID_HWUI_DITHER_H
19 
20 #include <GLES3/gl3.h>
21 
22 namespace android {
23 namespace uirenderer {
24 
25 class Caches;
26 class Extensions;
27 class Program;
28 
29 // Must be a power of two
30 #define DITHER_KERNEL_SIZE 4
31 // These must not use the .0f notation as they are used from GLSL
32 #define DITHER_KERNEL_SIZE_INV (1.0 / 4.0)
33 #define DITHER_KERNEL_SIZE_INV_SQUARE (1.0 / 16.0)
34 
35 /**
36  * Handles dithering for programs.
37  */
38 class Dither {
39 public:
40     Dither(Caches& caches);
41 
42     void clear();
43     void setupProgram(Program& program, GLuint* textureUnit);
44 
45 private:
46     void bindDitherTexture();
47 
48     Caches& mCaches;
49     bool mInitialized;
50     GLuint mDitherTexture;
51 };
52 
53 }; // namespace uirenderer
54 }; // namespace android
55 
56 #endif // ANDROID_HWUI_DITHER_H
57