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 
28 package org.webrtc;
29 
30 import 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.
38 public 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    */
GlTextureFrameBuffer(int pixelFormat)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    */
setSize(int width, int height)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 
getWidth()116   public int getWidth() {
117     return width;
118   }
119 
getHeight()120   public int getHeight() {
121     return height;
122   }
123 
getFrameBufferId()124   public int getFrameBufferId() {
125     return frameBufferId;
126   }
127 
getTextureId()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    */
release()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