Timer

ALLEGRO_TIMER

typedef struct ALLEGRO_TIMER ALLEGRO_TIMER;

This is an abstract data type representing a timer object. A timer object can act as an event source so can be casted to ALLEGRO_EVENT_SOURCE*.

ALLEGRO_USECS_TO_SECS

#define ALLEGRO_USECS_TO_SECS(x)      (x / 1000000.0)

Convert microseconds to seconds.

ALLEGRO_MSECS_TO_SECS

#define ALLEGRO_MSECS_TO_SECS(x)      (x / 1000.0)

Convert milliseconds to seconds.

ALLEGRO_BPS_TO_SECS

#define ALLEGRO_BPS_TO_SECS(x)        (1.0 / x)

Convert beats per second to seconds.

ALLEGRO_BPM_TO_SECS

#define ALLEGRO_BPM_TO_SECS(x)        (60.0 / x)

Convert beats per minute to seconds.

al_get_timer_count

long al_get_timer_count(const ALLEGRO_TIMER *timer)

Return the timer's counter value. The timer can be started or stopped.

al_get_timer_speed

double al_get_timer_speed(const ALLEGRO_TIMER *timer)

Return the timer's speed, in seconds.

al_install_timer

ALLEGRO_TIMER* al_install_timer(double speed_secs)

Install a new timer. If successful, a pointer to a new timer object is returned, otherwise NULL is returned. speed_secs is in seconds per "tick", and must be positive. The new timer is initially stopped.

The system driver must be installed before this function can be called.

Usage note: typical granularity is on the order of microseconds, but with some drivers might only be milliseconds.

al_set_timer_count

void al_set_timer_count(ALLEGRO_TIMER *timer, long new_count)

Change a timer's counter value. The timer can be started or stopped. COUNT value may be positive or negative, but will always be incremented by +1.

al_set_timer_speed

void al_set_timer_speed(ALLEGRO_TIMER *timer, double new_speed_secs)

Set the timer's speed, i.e. the rate at which its counter will be incremented when it is started. This can be done when the timer is started or stopped. If the timer is currently running, it is made to look as though the speed change occured precisely at the last tick.

speed_secs has exactly the same meaning as with al_install_timer.

al_start_timer

void al_start_timer(ALLEGRO_TIMER *timer)

Start the timer specified. From then, the timer's counter will increment at a constant rate, and it will begin generating events. Starting a timer that is already started does nothing.

al_stop_timer

void al_stop_timer(ALLEGRO_TIMER *timer)

Stop the timer specified. The timer's counter will stop incrementing and it will stop generating events. Stopping a timer that is already stopped does nothing.

al_timer_is_started

bool al_timer_is_started(const ALLEGRO_TIMER *timer)

Return true if the timer specified is currently started.

al_uninstall_timer

void al_uninstall_timer(ALLEGRO_TIMER *timer)

Uninstall the timer specified. If the timer is started, it will automatically be stopped before uninstallation. It will also automatically unregister the timer with any event queues.

Does nothing if passed the NULL pointer.