@Override
	public void onSurfaceCreated(GL10 glUnused, EGLConfig config) 
	{
		// Set the background clear color to gray.
		GLES20.glClearColor(0.5f, 0.5f, 0.5f, 0.5f);
	
		// Position the eye behind the origin.
		final float eyeX = 0.0f;
		final float eyeY = 0.0f;
		final float eyeZ = 1.5f;

		// We are looking toward the distance
		final float lookX = 0.0f;
		final float lookY = 0.0f;
		final float lookZ = -5.0f;

		// Set our up vector. This is where our head would be pointing were we holding the camera.
		final float upX = 0.0f;
		final float upY = 1.0f;
		final float upZ = 0.0f;

		/* Set the view matrix. This matrix can be said to represent the camera position.
		 NOTE: In OpenGL 1, a ModelView matrix is used, which is a 
                 combination of a model and view matrix. In OpenGL 2, we can keep track of these 
                 matrices separately if we choose.
                */
		Matrix.setLookAtM(mViewMatrix, 0, eyeX, eyeY, eyeZ, lookX, lookY, lookZ, upX, upY, upZ);

		final String vertexShader =
			"uniform mat4 u_MVPMatrix;      \n" // A constant representing the 
                                                            //combined model/view/projection matrix.
			
		  + "attribute vec4 a_Position;     \n"	// Per-vertex position information we will pass in.
		  + "attribute vec4 a_Color;        \n" // Per-vertex color information we will pass in.			  
		  
		  + "varying vec4 v_Color;          \n"	 // This will be passed into the fragment shader.
		  
		  + "void main()                    \n"	 // The entry point for our vertex shader.
		  + "{                              \n"
		  + "   v_Color = a_Color;          \n"	 // Pass the color through to the fragment shader. 
		  					 // It will be interpolated across the triangle.
		  + "   gl_Position = u_MVPMatrix   \n"  // gl_Position is a special variable used to 
                                                         //store the final position.
		  + "               * a_Position;   \n"  // Multiply the vertex by the matrix to get the final point in 			                                            			 
		  + "}                              \n";  // normalized screen coordinates.
		
		final String fragmentShader =
			"precision mediump float;       \n" // Set the default precision to medium. We don't need as high of a 
						            // precision in the fragment shader.				
		  + "varying vec4 v_Color;          \n"	 // This is the color from the vertex shader interpolated across the 
		  					 // triangle per fragment.			  
		  + "void main()                    \n"	 // The entry point for our fragment shader.
		  + "{                              \n"
		  + "   gl_FragColor = v_Color;     \n"	 // Pass the color directly through the pipeline.		  
		  + "}                              \n";												
		

		// Load in the vertex shader.
		int vertexShaderHandle = GLES20.glCreateShader(GLES20.GL_VERTEX_SHADER);

		if (vertexShaderHandle != 0) 
		{
			// Pass in the shader source.
			GLES20.glShaderSource(vertexShaderHandle, vertexShader);

			// Compile the shader.
			GLES20.glCompileShader(vertexShaderHandle);

			// Get the compilation status.
			final int[] compileStatus = new int[1];
			GLES20.glGetShaderiv(vertexShaderHandle, 
                            GLES20.GL_COMPILE_STATUS, compileStatus, 0);

			// If the compilation failed, delete the shader.
			if (compileStatus[0] == 0) 
			{				
				GLES20.glDeleteShader(vertexShaderHandle);
				vertexShaderHandle = 0;
			}
		}

		if (vertexShaderHandle == 0)
		{
			throw new RuntimeException("Error creating vertex shader.");
		}
		
		// Load in the fragment shader shader.
		int fragmentShaderHandle = GLES20.glCreateShader(
                     GLES20.GL_FRAGMENT_SHADER);

		if (fragmentShaderHandle != 0) 
		{
			// Pass in the shader source.
			GLES20.glShaderSource(fragmentShaderHandle, fragmentShader);

			// Compile the shader.
			GLES20.glCompileShader(fragmentShaderHandle);

			// Get the compilation status.
			final int[] compileStatus = new int[1];
			GLES20.glGetShaderiv(fragmentShaderHandle,
                            GLES20.GL_COMPILE_STATUS, compileStatus, 0);

			// If the compilation failed, delete the shader.
			if (compileStatus[0] == 0) 
			{				
				GLES20.glDeleteShader(fragmentShaderHandle);
				fragmentShaderHandle = 0;
			}
		}

		if (fragmentShaderHandle == 0)
		{
			throw new RuntimeException("Error creating fragment shader.");
		}
		
		// Create a program object and store the handle to it.
		int programHandle = GLES20.glCreateProgram();
		
		if (programHandle != 0) 
		{
			// Bind the vertex shader to the program.
			GLES20.glAttachShader(programHandle, vertexShaderHandle);			

			// Bind the fragment shader to the program.
			GLES20.glAttachShader(programHandle, fragmentShaderHandle);
			
			// Bind attributes
			GLES20.glBindAttribLocation(programHandle, 0, "a_Position");
			GLES20.glBindAttribLocation(programHandle, 1, "a_Color");
			
			// Link the two shaders together into a program.
			GLES20.glLinkProgram(programHandle);

			// Get the link status.
			final int[] linkStatus = new int[1];
			GLES20.glGetProgramiv(programHandle, GLES20.GL_LINK_STATUS, linkStatus, 0);

			// If the link failed, delete the program.
			if (linkStatus[0] == 0) 
			{				
				GLES20.glDeleteProgram(programHandle);
				programHandle = 0;
			}
		}
		
		if (programHandle == 0)
		{
			throw new RuntimeException("Error creating program.");
		}
        
        // Set program handles. These will later be used to pass in values to the program.
        mMVPMatrixHandle = GLES20.glGetUniformLocation(programHandle, "u_MVPMatrix");        
        mPositionHandle = GLES20.glGetAttribLocation(programHandle, "a_Position");
        mColorHandle = GLES20.glGetAttribLocation(programHandle, "a_Color");        
        
        // Tell OpenGL to use this program when rendering.
        GLES20.glUseProgram(programHandle);        
	}