Function normalize

docs/demo/spritejs.js:5161–5176

* Normalize a vec3 * * @param {vec3} out the receiving vector * @param {ReadonlyVec3} a vector to normalize * @returns {vec3} out

(out, a)

 */

function normalize(out, a) {
  var x = a[0];
  var y = a[1];
  var z = a[2];
  var len = x * x + y * y + z * z;

  if (len > 0) {
    //TODO: evaluate use of glm_invsqrt here?
    len = 1 / Math.sqrt(len);
  }

  out[0] = a[0] * len;
  out[1] = a[1] * len;
  out[2] = a[2] * len;
  return out;
}
/**
 * Calculates the dot product of two vec3's
 *