Circular property

Implementation

static Map<ETTypes,num Function(num,[num?])> Circular = {
  ETTypes.In:(amount,[power]) {
    return 1 - math.sqrt(1 - amount * amount);
  },
  ETTypes.Out:(amount,[power]) {
    return math.sqrt(1 - --amount * amount);
  },
  ETTypes.InOut:(amount,[power]) {
    if ((amount *= 2) < 1) {
      return -0.5 * (math.sqrt(1 - amount * amount) - 1);
    }
    return 0.5 * (math.sqrt(1 - (amount -= 2) * amount) + 1);
  },
};