/** Convert a Transformation to a float array in column major ordering, as used by OpenGL. */
 private static float[] transformationToFloat16(Matrix4f m) {
   float[] f = new float[16];
   for (int i = 0; i < 4; i++) for (int j = 0; j < 4; j++) f[j * 4 + i] = m.getElement(i, j);
   return f;
 }