al_fixhypot - Man Page
Allegro 5 API
Synopsis
#include <allegro5/allegro.h> al_fixed al_fixhypot(al_fixed x, al_fixed y)
Description
Fixed point hypotenuse (returns the square root of x*x + y*y
). This should be better than calculating the formula yourself manually, since the error is much smaller.
Info
Allegro reference manual