content: /*
   * Copyright (C) 2014 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.
   */
  
  package com.example.android.mediaeffects;
  
  import android.opengl.GLES20;
  
  public class GLToolbox {
  
      public static int loadShader(int shaderType, String source) {
          int shader = GLES20.glCreateShader(shaderType);
          if (shader != 0) {
              GLES20.glShaderSource(shader, source);
              GLES20.glCompileShader(shader);
              int[] compiled = new int[1];
              GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, compiled, 0);
              if (compiled[0] == 0) {
                  String info = GLES20.glGetShaderInfoLog(shader);
                  GLES20.glDeleteShader(shader);
                  throw new RuntimeException("Could not compile shader " + shaderType + ":" + info);
              }
          }
          return shader;
      }
  
      public static int createProgram(String vertexSource, String fragmentSource) {
          int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexSource);
          if (vertexShader == 0) {
              return 0;
          }
          int pixelShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentSource);
          if (pixelShader == 0) {
              return 0;
          }
  
          int program = GLES20.glCreateProgram();
          if (program != 0) {
              GLES20.glAttachShader(program, vertexShader);
              checkGlError("glAttachShader");
              GLES20.glAttachShader(program, pixelShader);
              checkGlError("glAttachShader");
              GLES20.glLinkProgram(program);
              int[] linkStatus = new int[1];
              GLES20.glGetProgramiv(program, GLES20.GL_LINK_STATUS, linkStatus,
                      0);
              if (linkStatus[0] != GLES20.GL_TRUE) {
                  String info = GLES20.glGetProgramInfoLog(program);
                  GLES20.glDeleteProgram(program);
                  throw new RuntimeException("Could not link program: " + info);
              }
          }
          return program;
      }
  
      public static void checkGlError(String op) {
          int error = GLES20.glGetError();
          if (error != GLES20.GL_NO_ERROR) {
              throw new RuntimeException(op + ": glError " + error);
          }
      }
  
      public static void initTexParams() {
          GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                  GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
          GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D,
                  GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);
          GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S,
                  GLES20.GL_CLAMP_TO_EDGE);
          GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T,
                  GLES20.GL_CLAMP_TO_EDGE);
      }
  
  }
  