public void calcEndDiffs() {
if(prev != null) {
Vector3 prevdiffnorm = prev.diff.copy().normalize();
Vector3 thisdiffnorm = diff.copy().normalize();
prevdiff = thisdiffnorm.copy().add(prevdiffnorm).normalize();
sinprev = (float) Math.sin(thisdiffnorm.angle(prevdiffnorm.multiply(-1)) / 2);
} else {
prevdiff = diff.copy().normalize();
sinprev = 1;
}