/**
 * convert hex colors to the normalized webgl colors [0, 1]
 */
export const hexToNormalized = (hex: string) => {

  // expand shorthand form (e.g. "03F") to full form (e.g. "0033FF")
  const shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
  hex = hex.replace(shorthandRegex, (_m, r, g, b) => {
    return r + r + g + g + b + b;
  });

  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  return result ? [
    parseInt(result[1], 16) / 255,
    parseInt(result[2], 16) / 255,
    parseInt(result[3], 16) / 255
  ] : [];
};