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/*
* Copyright 2015 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
package org.webrtc;
import android.opengl.GLES20;
/**
* Helper class for handling OpenGL framebuffer with only color attachment and no depth or stencil
* buffer. Intended for simple tasks such as texture copy, texture downscaling, and texture color
* conversion. This class is not thread safe and must be used by a thread with an active GL context.
*/
// TODO(magjed): Add unittests for this class.
public class GlTextureFrameBuffer {
private final int pixelFormat;
private int frameBufferId;
private int textureId;
private int width;
private int height;
/**
* Generate texture and framebuffer resources. An EGLContext must be bound on the current thread
* when calling this function. The framebuffer is not complete until setSize() is called.
*/
public GlTextureFrameBuffer(int pixelFormat) {
switch (pixelFormat) {
case GLES20.GL_LUMINANCE:
case GLES20.GL_RGB:
case GLES20.GL_RGBA:
this.pixelFormat = pixelFormat;
break;
default:
throw new IllegalArgumentException("Invalid pixel format: " + pixelFormat);
}
this.width = 0;
this.height = 0;
}
/**
* (Re)allocate texture. Will do nothing if the requested size equals the current size. An
* EGLContext must be bound on the current thread when calling this function. Must be called at
* least once before using the framebuffer. May be called multiple times to change size.
*/
public void setSize(int width, int height) {
if (width <= 0 || height <= 0) {
throw new IllegalArgumentException("Invalid size: " + width + "x" + height);
}
if (width == this.width && height == this.height) {
return;
}
this.width = width;
this.height = height;
// Lazy allocation the first time setSize() is called.
if (textureId == 0) {
textureId = GlUtil.generateTexture(GLES20.GL_TEXTURE_2D);
}
if (frameBufferId == 0) {
final int frameBuffers[] = new int[1];
GLES20.glGenFramebuffers(1, frameBuffers, 0);
frameBufferId = frameBuffers[0];
}
// Allocate texture.
GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId);
GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, pixelFormat, width, height, 0, pixelFormat,
GLES20.GL_UNSIGNED_BYTE, null);
GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
GlUtil.checkNoGLES2Error("GlTextureFrameBuffer setSize");
// Attach the texture to the framebuffer as color attachment.
GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, frameBufferId);
GLES20.glFramebufferTexture2D(
GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0, GLES20.GL_TEXTURE_2D, textureId, 0);
// Check that the framebuffer is in a good state.
final int status = GLES20.glCheckFramebufferStatus(GLES20.GL_FRAMEBUFFER);
if (status != GLES20.GL_FRAMEBUFFER_COMPLETE) {
throw new IllegalStateException("Framebuffer not complete, status: " + status);
}
GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
}
public int getWidth() {
return width;
}
public int getHeight() {
return height;
}
/** Gets the OpenGL frame buffer id. This value is only valid after setSize() has been called. */
public int getFrameBufferId() {
return frameBufferId;
}
/** Gets the OpenGL texture id. This value is only valid after setSize() has been called. */
public int getTextureId() {
return textureId;
}
/**
* Release texture and framebuffer. An EGLContext must be bound on the current thread when calling
* this function. This object should not be used after this call.
*/
public void release() {
GLES20.glDeleteTextures(1, new int[] {textureId}, 0);
textureId = 0;
GLES20.glDeleteFramebuffers(1, new int[] {frameBufferId}, 0);
frameBufferId = 0;
width = 0;
height = 0;
}
}
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