al_set_mouse_wheel_precision(1) Allegro 5 API


#include <allegro5/allegro.h>
void al_set_mouse_wheel_precision(int precision)


Sets the precision of the mouse wheel (the z and w coordinates). This precision manifests itself as a multiplier on the dz and dw fields in mouse events. It also affects the z and w fields of events and ALLEGRO_MOUSE_STATE(3alleg5), but not in a simple way if you alter the precision often, so it is suggested to reset those axes to 0 when you change precision. Setting this to a high value allows you to detect small changes in those two axes for some high precision mice. A flexible way of using this precision is to set it to a high value (120 is likely sufficient for most, if not all, mice) and use a floating point dz and dw like so:

al_wait_for_event(event_queue, &event);
if (event.type == ALLEGRO_EVENT_MOUSE_AXES) {
  double dz = (double) / al_get_mouse_wheel_precision();
  /* Use dz in some way... */

Precision is set to 1 by default. It is impossible to set it to a lower precision than that.