tributeLocation, size, type, normalize, stride, offset);


  function radToDeg(r) {
    return r * 180 / Math.PI;
  }

  function degToRad(d) {
    return d * Math.PI / 180;
  }

  var fieldOfViewRadians = degToRad(60);
  var fRotationRadians = 0;
  var shininess = 150;
  var lightRotationX = 0;
  var lightRotationY = 0;
  var lightDirection = [0, 0, 1];  // this is computed in updateScene
  var innerLimit = degToRad(10);
  var outerLimit = degToRad(20);

  drawScene();

  // Setup a ui.
  webglLessonsUI.se