b488004289
Float textures offer better precision for dithering. In addition this change removes two uniforms from gradient shaders. These uniforms were used to dither gradients but their value is a build time constant. Instead we hardcode the value directly in the shader source at compile time. Change-Id: I05e9fd3eef93771843bbd91b453274452dfaefee
92 lines
3.1 KiB
C++
92 lines
3.1 KiB
C++
/*
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* Copyright (C) 2012 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "Caches.h"
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#include "Dither.h"
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namespace android {
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namespace uirenderer {
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///////////////////////////////////////////////////////////////////////////////
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// Lifecycle
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///////////////////////////////////////////////////////////////////////////////
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void Dither::bindDitherTexture() {
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if (!mInitialized) {
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bool useFloatTexture = Extensions::getInstance().getMajorGlVersion() >= 3;
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glGenTextures(1, &mDitherTexture);
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glBindTexture(GL_TEXTURE_2D, mDitherTexture);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
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if (useFloatTexture) {
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float dither = 1.0f / (255.0f * DITHER_KERNEL_SIZE * DITHER_KERNEL_SIZE);
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const GLfloat pattern[] = {
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0 * dither, 8 * dither, 2 * dither, 10 * dither,
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12 * dither, 4 * dither, 14 * dither, 6 * dither,
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3 * dither, 11 * dither, 1 * dither, 9 * dither,
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15 * dither, 7 * dither, 13 * dither, 5 * dither
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};
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glPixelStorei(GL_UNPACK_ALIGNMENT, sizeof(GLfloat));
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glTexImage2D(GL_TEXTURE_2D, 0, GL_R16F, DITHER_KERNEL_SIZE, DITHER_KERNEL_SIZE, 0,
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GL_RED, GL_FLOAT, &pattern);
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} else {
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const uint8_t pattern[] = {
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0, 8, 2, 10,
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12, 4, 14, 6,
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3, 11, 1, 9,
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15, 7, 13, 5
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};
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glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
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glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, DITHER_KERNEL_SIZE, DITHER_KERNEL_SIZE, 0,
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GL_ALPHA, GL_UNSIGNED_BYTE, &pattern);
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}
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mInitialized = true;
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} else {
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glBindTexture(GL_TEXTURE_2D, mDitherTexture);
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}
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}
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void Dither::clear() {
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if (mInitialized) {
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glDeleteTextures(1, &mDitherTexture);
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}
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}
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///////////////////////////////////////////////////////////////////////////////
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// Program management
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///////////////////////////////////////////////////////////////////////////////
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void Dither::setupProgram(Program* program, GLuint* textureUnit) {
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GLuint textureSlot = (*textureUnit)++;
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Caches::getInstance().activeTexture(textureSlot);
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bindDitherTexture();
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glUniform1i(program->getUniform("ditherSampler"), textureSlot);
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}
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}; // namespace uirenderer
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}; // namespace android
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