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/*
* Copyright 2013 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 <GLES/gl.h>
#include <cutils/compiler.h>
#include "GLES10RenderEngine.h"
// ---------------------------------------------------------------------------
namespace android {
// ---------------------------------------------------------------------------
GLES10RenderEngine::~GLES10RenderEngine() {
}
void GLES10RenderEngine::setupLayerBlending(
bool premultipliedAlpha, bool opaque, int alpha) {
// OpenGL ES 1.0 doesn't support texture combiners.
// This path doesn't properly handle opaque layers that have non-opaque
// alpha values. The alpha channel will be copied into the framebuffer or
// screenshot, so if the framebuffer or screenshot is blended on top of
// something else, whatever is below the window will incorrectly show
// through.
if (CC_UNLIKELY(alpha < 0xFF)) {
GLfloat floatAlpha = alpha * (1.0f / 255.0f);
if (premultipliedAlpha) {
glColor4f(floatAlpha, floatAlpha, floatAlpha, floatAlpha);
} else {
glColor4f(1.0f, 1.0f, 1.0f, floatAlpha);
}
glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
} else {
glTexEnvx(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
}
if (alpha < 0xFF || !opaque) {
glEnable(GL_BLEND);
glBlendFunc(premultipliedAlpha ? GL_ONE : GL_SRC_ALPHA,
GL_ONE_MINUS_SRC_ALPHA);
} else {
glDisable(GL_BLEND);
}
}
// ---------------------------------------------------------------------------
}; // namespace android
// ---------------------------------------------------------------------------
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