remoting/android/java/src/org/chromium/chromoting/ShaderHelper.java

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 package org.chromium.chromoting;
   6
   7 import android.opengl.GLES20;
   8
   9 import org.chromium.base.Log;
  10
  11 /**
  12  * Helper class for working with OpenGL shaders and programs.
  13  */
  14 public class ShaderHelper {
  15     private static final String TAG = "cr.ShaderHelper";
  16
  17     /**
  18      * Compile a shader.
  19      *
  20      * @param shaderType The shader type.
  21      * @param shaderSource The shader source code.
  22      * @return An OpenGL handle to the shader.
  23      */
  24     public static int compileShader(int shaderType, String shaderSource) {
  25         int shaderHandle = GLES20.glCreateShader(shaderType);
  26
  27         if (shaderHandle != 0) {
  28             // Pass in the shader source.
  29             GLES20.glShaderSource(shaderHandle, shaderSource);
  30
  31             // Compile the shader.
  32             GLES20.glCompileShader(shaderHandle);
  33
  34             // Get the compilation status.
  35             int[] compileStatus = new int[1];
  36             GLES20.glGetShaderiv(shaderHandle, GLES20.GL_COMPILE_STATUS, compileStatus, 0);
  37
  38             // If the compilation failed, delete the shader.
  39             if (compileStatus[0] == 0) {
  40                 Log.e(TAG, "Error compiling shader: " + GLES20.glGetShaderInfoLog(shaderHandle));
  41                 GLES20.glDeleteShader(shaderHandle);
  42                 shaderHandle = 0;
  43             }
  44         }
  45
  46         if (shaderHandle == 0) {
  47             // TODO(shichengfeng): Handle Exception gracefully.
  48             throw new RuntimeException("Error creating shader.");
  49         }
  50
  51         return shaderHandle;
  52     }
  53
  54     /**
  55      * Compile and link a program.
  56      *
  57      * @param vertexShaderHandle An OpenGL handle to an already-compiled vertex shader.
  58      * @param fragmentShaderHandle An OpenGL handle to an already-compiled fragment shader.
  59      * @param attributes Attributes that need to be bound to the program.
  60      * @return An OpenGL handle to the program.
  61      */
  62     public static int createAndLinkProgram(int vertexShaderHandle,
  63             int fragmentShaderHandle, String[] attributes) {
  64         int programHandle = GLES20.glCreateProgram();
  65
  66         if (programHandle != 0) {
  67             // Bind the vertex shader to the program.
  68             GLES20.glAttachShader(programHandle, vertexShaderHandle);
  69
  70             // Bind the fragment shader to the program.
  71             GLES20.glAttachShader(programHandle, fragmentShaderHandle);
  72
  73             // Bind attributes
  74             if (attributes != null) {
  75                 int size = attributes.length;
  76                 for (int i = 0; i < size; i++) {
  77                     GLES20.glBindAttribLocation(programHandle, i, attributes[i]);
  78                 }
  79             }
  80
  81             // Link the two shaders together into a program.
  82             GLES20.glLinkProgram(programHandle);
  83
  84             // Get the link status.
  85             int[] linkStatus = new int[1];
  86             GLES20.glGetProgramiv(programHandle, GLES20.GL_LINK_STATUS, linkStatus, 0);
  87
  88             // If the link failed, delete the program.
  89             if (linkStatus[0] == 0) {
  90                 Log.e(TAG, "Error compiling program: " + GLES20.glGetProgramInfoLog(programHandle));
  91                 GLES20.glDeleteProgram(programHandle);
  92                 programHandle = 0;
  93             }
  94         }
  95
  96         if (programHandle == 0) {
  97             // TODO(shichengfeng): Handle Exception gracefully.
  98             throw new RuntimeException("Error creating program.");
  99         }
 100
 101         return programHandle;
 102     }
 103 }