al_set_mouse_wheel_precision - Allegro 5 API
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#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(3), 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:
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al_set_mouse_wheel_precision(120);
ALLEGRO_EVENT event;
al_wait_for_event(event_queue, &event);
if (event.type == ALLEGRO_EVENT_MOUSE_AXES) {
double dz = (double)event.mouse.dz / 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.
al_get_mouse_wheel_precision(3)