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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "Caches.h"
#include "Dither.h"
namespace android {
namespace uirenderer {
///////////////////////////////////////////////////////////////////////////////
// Lifecycle
///////////////////////////////////////////////////////////////////////////////
Dither::Dither(Caches& caches)
: mCaches(caches)
, mInitialized(false)
, mDitherTexture(0) {
}
void Dither::bindDitherTexture() {
if (!mInitialized) {
glGenTextures(1, &mDitherTexture);
mCaches.textureState().bindTexture(mDitherTexture);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
if (mCaches.extensions().hasFloatTextures()) {
// We use a R16F texture, let's remap the alpha channel to the
// red channel to avoid changing the shader sampling code on GL ES 3.0+
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_SWIZZLE_A, GL_RED);
float dither = 1.0f / (255.0f * DITHER_KERNEL_SIZE * DITHER_KERNEL_SIZE);
const GLfloat pattern[] = {
0 * dither, 8 * dither, 2 * dither, 10 * dither,
12 * dither, 4 * dither, 14 * dither, 6 * dither,
3 * dither, 11 * dither, 1 * dither, 9 * dither,
15 * dither, 7 * dither, 13 * dither, 5 * dither
};
glPixelStorei(GL_UNPACK_ALIGNMENT, sizeof(GLfloat));
glTexImage2D(GL_TEXTURE_2D, 0, GL_R16F, DITHER_KERNEL_SIZE, DITHER_KERNEL_SIZE, 0,
GL_RED, GL_FLOAT, &pattern);
} else {
const uint8_t pattern[] = {
0, 8, 2, 10,
12, 4, 14, 6,
3, 11, 1, 9,
15, 7, 13, 5
};
glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, DITHER_KERNEL_SIZE, DITHER_KERNEL_SIZE, 0,
GL_ALPHA, GL_UNSIGNED_BYTE, &pattern);
}
mInitialized = true;
} else {
mCaches.textureState().bindTexture(mDitherTexture);
}
}
void Dither::clear() {
if (mInitialized) {
mCaches.textureState().deleteTexture(mDitherTexture);
mInitialized = false;
}
}
///////////////////////////////////////////////////////////////////////////////
// Program management
///////////////////////////////////////////////////////////////////////////////
void Dither::setupProgram(Program& program, GLuint* textureUnit) {
GLuint textureSlot = (*textureUnit)++;
mCaches.textureState().activateTexture(textureSlot);
bindDitherTexture();
glUniform1i(program.getUniform("ditherSampler"), textureSlot);
}
}; // namespace uirenderer
}; // namespace android
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