title: OpenGL shader cant bind attribute
body: <p>i've got three glsl attributes in my vertex shader</p>
  
  <pre><code>attribute highp   vec4  Position;
  attribute mediump vec4  UV;
  attribute mediump vec3  Normal;
  </code></pre>
  
  <p>that im binding using</p>
  
  <pre><code>glBindAttribLocation(program, 0, "Position");
  glBindAttribLocation(program, 1, "Normal");
  glBindAttribLocation(program, 2, "UV");
  </code></pre>
  
  <p>However, i'm getting an error</p>
  
  <p><em>Could not find vertex shader attribute 'Normal' to match BindAttributeLocation request.</em></p>
  
  <p>Why can it find the Position and UV attributes but not the Normal attribute. </p>
  
  <p>Any help would be highly appreciated as i'm pretty confused.</p>
  
  <p>Cheers</p>
  
  <p>Edit:
  I have the same issue on Android OpenGLES20. 
  I'll add sample code : the rest of the class is the official GLSurfaceView tutorial</p>
  
  <pre><code>public void onSurfaceCreated(GL10 glUnused, EGLConfig config) {
  
      String mVertexShader =  "uniform mat4 uMVPMatrix;\n " +
              "attribute vec4 aPosition;\n " +
              "attribute vec4 aNormal; \n " + //this is the line I added
              "attribute vec2 aTextureCoord;\n " +
              "varying vec2 vTextureCoord;\n " +
              "void main() {\n " +
              "gl_Position = uMVPMatrix * aPosition;\n" +
              "  vTextureCoord = aTextureCoord;\n" +
              "}\n";
  
      mProgram = createProgram(mVertexShader, mFragmentShader); // cf tutorial
      if (mProgram == 0) {
          return;
      }
      initShaderHandles(); //initializes the rest of the handles (cf tutorial)
  
       // my little additional code
      int maNormalHandle = GLES20.glGetAttribLocation(mProgram, "aNormal");
      Log.d("ATTRIB LOCATION Normal: ", maNormalHandle + "");
      checkGlError("glGetAttribLocation normal");
      if (maNormalHandle == -1) {
          throw new RuntimeException(
                  "Could not get attrib location for normal");
      }
      // ...and we crash.
  
  }
  </code></pre>