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SAPER

1 PAUSE user

Kartik Thakore
and 1 contributors

NAME

SDL::Events - Bindings to the Events Category in SDL API

CATEGORY

Core, Events

SYNOPSIS

Most likely you just want to know how to get events for you app. use SDL; use SDL::Event; use SDL::Events;

  SDL::init(SDL_INIT_VIDEO); # Event can only be grabbed in the same thread as this 

  ...
 
  my $event = SDL::Event->new(); # notices 'Event' ne 'Events'

  while( 1 )
        {
          SDL::Events::pump_events();    
         while(  SDL::Events::poll_event($event) )
         {
                #check by event type
                on_active() if $event->type == SDL_ACTIVEEVENT; 
                ...
         }
        }

DESCRIPTION

METHODS

pump_events

Pumps the event loop, gathering events from the input devices.

        pump_events();

pump_events gathers all the pending input information from devices and places it on the event queue. Without calls to pump_events no events would ever be placed on the queue. Often the need for calls to pump_events is hidden from the user since poll_event and wait_event implicitly call pump_events. However, if you are not polling or waiting for events (e.g. you are filtering them), then you must call pump_events to force an event queue update.

peep_events (event, num_events, action, mask)

Checks the event queue for messages and optionally returns them.

        my $num_peep_events = SDL::Events::peep_events($event, 127, SDL_PEEKEVENT, SDL_ALLEVENTS);

If action is SDL_ADDEVENT, up to numevents events will be added to the back of the event queue.

If action is SDL_PEEKEVENT, up to numevents events at the front of the event queue, matching mask, will be returned and will not be removed from the queue.

If action is SDL_GETEVENT, up to numevents events at the front of the event queue, matching mask, will be returned and will be removed from the queue.

The mask parameter is a bitwise OR of SDL::Events::SDL_EVENTMASK(event_type), for all event types you are interested in

This function is thread-safe.

You may have to call pump_events before calling this function. Otherwise, the events may not be ready to be filtered when you call peep_events.

Examples of mask:

SDL_EVENTMASK (SDL_KEYUP)
(SDL_EVENTMASK (SDL_MOUSEBUTTONDOWN) | SDL_EVENTMASK (SDL_MOUSEBUTTONUP))
SDL_ALLEVENTS
SDL_KEYUPMASK
SDL_ALLEVENTS ^ SDL_QUITMASK

RETURN

Number of Events actually stored or -1 if there was an error

poll_event($event)

Polls for currently pending events.

If $event is not NULL, the next event is removed from the queue and stored in the SDL::Event structure pointed to by $event.

As this function implicitly calls pump_events, you can only call this function in the thread that set the video mode with SDL::Video::set_video_mode.

RETURN

Returns 1 if there are any pending events, or 0 if there are none available.

push_event($event)

Pushes an event onto the event queue

The event queue can actually be used as a two way communication channel. Not only can events be read from the queue, but the user can also push their own events onto it. event is a pointer to the event structure you wish to push onto the queue. The event is copied into the queue, and the caller may dispose of the memory pointed to after push_event returns.

Note: Pushing device input events onto the queue doesn't modify the state of the device within SDL.

This function is thread safe, and can be called from other threads safely.

RETURN

Returns 0 on success or -1 if the event couldn't be pushed.

wait_event($event)

Waits indefinitely for the next available $event, returning 0 if there was an error while waiting for events, 1 otherwise.

If $event is not NULL, the next event is removed from the queue and stored in $event.

As this function implicitly calls SDL_PumpEvents, you can only call this function in the thread that SDL::Video::set_video_mode.

RETURN

0 if there was an error while waiting for events, 1 otherwise

SEE ALSO

SDL::Event, SDL::Video