// effect routine

last_letter = numletters - 1;
if (last_letter){
 if (sub_order < 2){
  letter_perc = letter / last_letter;
  if (sub_order == 1) letter_perc = 1 - letter_perc;
 } else if (sub_order < 4){
  my_letter = 2 * letter;
  if (my_letter >= numletters) my_letter = 2 * numletters - my_letter - 2;
  letter_perc = my_letter / last_letter;
  if (sub_order == 3) letter_perc = 1 - letter_perc;
 } else {
  letter_perc = frame / lastsubframe;
 }
 perc = Math.min(1, Math.max(0, 2 * frame / lastsubframe - letter_perc));
} else perc = frame / lastsubframe;
if (reverse_sub_effect == true) perc = 1 - perc;
xrotate = perc * 360 * x_rotations;
zrotate = perc * 360 * z_rotations;
tx = -Math.sin(perc * 2 * deg90) * max_delta;
ty = -Math.sin(perc * 2 * deg90) * max_delta;
tz = -Math.sin(perc * 2 * deg90) * max_delta;
