1/*
2 * libjingle
3 * Copyright 2015 Google Inc.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are met:
7 *
8 *  1. Redistributions of source code must retain the above copyright notice,
9 *     this list of conditions and the following disclaimer.
10 *  2. Redistributions in binary form must reproduce the above copyright notice,
11 *     this list of conditions and the following disclaimer in the documentation
12 *     and/or other materials provided with the distribution.
13 *  3. The name of the author may not be used to endorse or promote products
14 *     derived from this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28package org.webrtc;
29
30import android.opengl.GLES20;
31
32/**
33 * Helper class for handling OpenGL framebuffer with only color attachment and no depth or stencil
34 * buffer. Intended for simple tasks such as texture copy, texture downscaling, and texture color
35 * conversion.
36 */
37// TODO(magjed): Add unittests for this class.
38public class GlTextureFrameBuffer {
39  private final int frameBufferId;
40  private final int textureId;
41  private final int pixelFormat;
42  private int width;
43  private int height;
44
45  /**
46   * Generate texture and framebuffer resources. An EGLContext must be bound on the current thread
47   * when calling this function. The framebuffer is not complete until setSize() is called.
48   */
49  public GlTextureFrameBuffer(int pixelFormat) {
50    switch (pixelFormat) {
51      case GLES20.GL_LUMINANCE:
52      case GLES20.GL_RGB:
53      case GLES20.GL_RGBA:
54        this.pixelFormat = pixelFormat;
55        break;
56      default:
57        throw new IllegalArgumentException("Invalid pixel format: " + pixelFormat);
58    }
59
60    textureId = GlUtil.generateTexture(GLES20.GL_TEXTURE_2D);
61    this.width = 0;
62    this.height = 0;
63
64    // Create framebuffer object and bind it.
65    final int frameBuffers[] = new int[1];
66    GLES20.glGenFramebuffers(1, frameBuffers, 0);
67    frameBufferId = frameBuffers[0];
68    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, frameBufferId);
69    GlUtil.checkNoGLES2Error("Generate framebuffer");
70
71    // Attach the texture to the framebuffer as color attachment.
72    GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0,
73        GLES20.GL_TEXTURE_2D, textureId, 0);
74    GlUtil.checkNoGLES2Error("Attach texture to framebuffer");
75
76    // Restore normal framebuffer.
77    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
78  }
79
80  /**
81   * (Re)allocate texture. Will do nothing if the requested size equals the current size. An
82   * EGLContext must be bound on the current thread when calling this function. Must be called at
83   * least once before using the framebuffer. May be called multiple times to change size.
84   */
85  public void setSize(int width, int height) {
86    if (width == 0 || height == 0) {
87      throw new IllegalArgumentException("Invalid size: " + width + "x" + height);
88    }
89    if (width == this.width && height == this.height) {
90      return;
91    }
92    this.width = width;
93    this.height = height;
94
95    // Bind our framebuffer.
96    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, frameBufferId);
97    GlUtil.checkNoGLES2Error("glBindFramebuffer");
98
99    // Allocate texture.
100    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
101    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId);
102    GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, pixelFormat, width, height, 0, pixelFormat,
103        GLES20.GL_UNSIGNED_BYTE, null);
104
105    // Check that the framebuffer is in a good state.
106    final int status = GLES20.glCheckFramebufferStatus(GLES20.GL_FRAMEBUFFER);
107    if (status != GLES20.GL_FRAMEBUFFER_COMPLETE) {
108      throw new IllegalStateException("Framebuffer not complete, status: " + status);
109    }
110
111    // Restore normal framebuffer.
112    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
113    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
114  }
115
116  public int getWidth() {
117    return width;
118  }
119
120  public int getHeight() {
121    return height;
122  }
123
124  public int getFrameBufferId() {
125    return frameBufferId;
126  }
127
128  public int getTextureId() {
129    return textureId;
130  }
131
132  /**
133   * Release texture and framebuffer. An EGLContext must be bound on the current thread when calling
134   * this function. This object should not be used after this call.
135   */
136  public void release() {
137    GLES20.glDeleteTextures(1, new int[] {textureId}, 0);
138    GLES20.glDeleteFramebuffers(1, new int[] {frameBufferId}, 0);
139    width = 0;
140    height = 0;
141  }
142}
143