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 #include "Caches.h" 18 #include "Dither.h" 19 20 namespace android { 21 namespace uirenderer { 22 23 /////////////////////////////////////////////////////////////////////////////// 24 // Lifecycle 25 /////////////////////////////////////////////////////////////////////////////// 26 27 void Dither::bindDitherTexture() { 28 if (!mInitialized) { 29 bool useFloatTexture = Extensions::getInstance().getMajorGlVersion() >= 3; 30 31 glGenTextures(1, &mDitherTexture); 32 glBindTexture(GL_TEXTURE_2D, mDitherTexture); 33 34 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST); 35 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST); 36 37 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); 38 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); 39 40 if (useFloatTexture) { 41 // We use a R16F texture, let's remap the alpha channel to the 42 // red channel to avoid changing the shader sampling code on GL ES 3.0+ 43 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_A, GL_RED); 44 45 float dither = 1.0f / (255.0f * DITHER_KERNEL_SIZE * DITHER_KERNEL_SIZE); 46 const GLfloat pattern[] = { 47 0 * dither, 8 * dither, 2 * dither, 10 * dither, 48 12 * dither, 4 * dither, 14 * dither, 6 * dither, 49 3 * dither, 11 * dither, 1 * dither, 9 * dither, 50 15 * dither, 7 * dither, 13 * dither, 5 * dither 51 }; 52 53 glPixelStorei(GL_UNPACK_ALIGNMENT, sizeof(GLfloat)); 54 glTexImage2D(GL_TEXTURE_2D, 0, GL_R16F, DITHER_KERNEL_SIZE, DITHER_KERNEL_SIZE, 0, 55 GL_RED, GL_FLOAT, &pattern); 56 } else { 57 const uint8_t pattern[] = { 58 0, 8, 2, 10, 59 12, 4, 14, 6, 60 3, 11, 1, 9, 61 15, 7, 13, 5 62 }; 63 64 glPixelStorei(GL_UNPACK_ALIGNMENT, 1); 65 glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, DITHER_KERNEL_SIZE, DITHER_KERNEL_SIZE, 0, 66 GL_ALPHA, GL_UNSIGNED_BYTE, &pattern); 67 } 68 69 mInitialized = true; 70 } else { 71 glBindTexture(GL_TEXTURE_2D, mDitherTexture); 72 } 73 } 74 75 void Dither::clear() { 76 if (mInitialized) { 77 glDeleteTextures(1, &mDitherTexture); 78 mInitialized = false; 79 } 80 } 81 82 /////////////////////////////////////////////////////////////////////////////// 83 // Program management 84 /////////////////////////////////////////////////////////////////////////////// 85 86 void Dither::setupProgram(Program* program, GLuint* textureUnit) { 87 GLuint textureSlot = (*textureUnit)++; 88 Caches::getInstance().activeTexture(textureSlot); 89 90 bindDitherTexture(); 91 92 glUniform1i(program->getUniform("ditherSampler"), textureSlot); 93 } 94 95 }; // namespace uirenderer 96 }; // namespace android 97
