f(!isWebGL2) {
            document.getElementById('info').innerHTML = 'WebGL 2 is not available.  See <a href="https://www.khronos.org/webgl/wiki/Getting_a_WebGL_Implementation">How to get a WebGL 2 implementation</a>';
            return;
        }

        // -- Init program
        var program = createProgram(gl, getShaderSource('vs'), getShaderSource('fs'));
        var mvpLocation = gl.getUniformLocation(program, 'MVP');
        var diffuseLocation = gl.getUniformLocation(program, 'diffuse');

       