SDL::Events - Bindings to the Events Category in SDL API
Core, Events
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;
...
}
}
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.
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:
Number of Events actually stored or -1 if there was an error
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.
Returns 1 if there are any pending events, or 0 if there are none available.
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.
Returns 0 on success or -1 if the event couldn't be pushed.
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.
0 if there was an error while waiting for events, 1 otherwise
Sets up a filter to process all events
my $filter = sub { if($_[0]->type == SDL_ACTIVEEVENT){ return 0} else{ return 1; }};
SDL::Events::set_event_filter($filter);
set_event_filter takes a coderef that it checks all events again. The callback gets a event in the stack
sub { my $event_to_test = shift; ...}
to filter the event return a 0, to pass the filter return a 1.
One Caveat is if you are filterign SDL_QUITEVENT the event will be filtered if it is non-intterupt call ( Window closes normally ). If it is a interrupt SDL_QUITEVENT it will be process on the next event poll.
Events pushed onto to the queue with SDL::Events::push_events or SDL::Events::peep_events do not get filtered.
This callback may run in a different thread.
Get a snapshot of the current keyboard state
my $keys_ref = SDL::Events::get_key_state(); print $keys_ref->[SDLK_RETURN]; # 1 if pressed , 0 if not pressed
Use SDL::Events::pump_events to update the state array.
This function gives you the current state after all events have been processed, so if a key or button has been pressed and released before you process events, then the pressed state will never show up in the get_key_state call.
This function doesn't take into account whether shift has been pressed or not.
Get the state of the modifier keys
Returns the current state of modifier keys
Return value is an OR'd combination of KMOD_*
SDL::Events::pump_events; #get latest mod_state in buffers my $mod_state = SDL::Events::get_mod_state(); # Check which ones are pressed with # no mod pressed? print 'no_mod' if ( $mod_state & KMOD_NONE ); # CTRL or ALT print 'ctrl alt' if ($mod_state & KMOD_CTRL || $mod_state & KMOD_ALT );
same as KMOD_LCTRL|KMOD_RCTRL
same as KMOD_LSHIFT|KMOD_RSHIFT
same as KMOD_LALT|KMOD_RALT
same as KMOD_LMETA|KMOD_RMETA
Get the state of the modifier keys
The inverse of SDL::Events::get_mod_state allows you to impose modifier key states on your application.
Simply pass your desired modifier states into $modstate. This value can be a OR'd combination of any KMOD* constant.
my $modstate = KMOD_LMETA | KMOD_LSHIFT;
Any KMOD_* constant see SDL::Events::get_mod_state for constants. SDL::Events::set_mod_state( $modstate );
Allows you to set the state of processing certain events
SDL::Events::event_state( $type, $state );
A list of $type(s) can be found in SDL::Event
The event of $type will be automatically dropper from the event queue and will not be filtered.
The event of $type will be processed normally. This is default.
The current processing state of the $type will be returned
Gets the name of the a SDL virtual keysym
my $event = SDL::Event->new();
while( SDL::Events::poll_event($event) )
{
my $key = $event->key_sym;
$key_str = SDL::Events::get_key_name($key);
}
Returns a string with the name of the key sym.
Enable/Disable UNICODE translation
my $previous_translation_mode = SDL::Events::enable_unicode( 1 ); #enable
$previous_translation_mode = SDL::Events::enable_unicode( 0 ); #disables
To obtain the character codes corresponding to received keyboard events, Unicode translation must first be turned on using this function. The translation incurs a slight overhead for each keyboard event and is therefore disabled by default. For each subsequently recieved key down event, the unicode member of the SDL::Event::key_sym provided structure will be then contain the corresponding character code, or otherwise zero.
A value of 1 for enabling, 0 for disabling and -1 for unchanged. -1 is usefull for querying the current translation mode.
Only key press events will be translated not release events.
Returns the previous translation mode as (1,0).
Sets keyboard repeat rate
my $success = SDL::Events::enable_key_repeat( $delay, $interval );
Enables or disables the keyboard repeat rate. $delay specifies how long the key must be pressed before it begins repeating, it then repleats at the speed specified by $interval. Both $delay and $interval are expressed in milliseconds.
Setting $delay to 0 disables key repeating completely. Good default values are SDL_DEFAULT_REPEAT_DELAY and SDL_DEFAULT_REPEAT_INTERVAL.
Return 0 on success and -1 on fail.
Retrives the current state of the mouse
my ($mask,$x,$y) = @{ SDL::Events::get_mouse_state( ) };
print 'Button Left pressed' if ($mask & SDL_BUTTON_LMASK);
print 'Button Right pressed' if ($mask & SDL_BUTTON_RMASK);
print 'Button Middle pressed' if ($mask & SDL_BUTTON_MMASK);
print $x.','.$y;
The current button state is returned as a button $bitmask, which can be tested using the the above constants
Retrives the current relative state of the mouse
my ($mask,$x,$y) = @{ SDL::Events::get_mouse_state( ) };
print 'Button Left pressed' if ($mask & SDL_BUTTON_LMASK);
print 'Button Right pressed' if ($mask & SDL_BUTTON_RMASK);
print 'Button Middle pressed' if ($mask & SDL_BUTTON_MMASK);
print $x.','.$y; # this is relative to the last postion of the mouse
The current button state is returned as a button $bitmask, which can be tested using the the above constants
Gets the state of the application
my $app_state = SDL::Events::get_app_state();
The $app_state is a bitwise combination of:
Application has mouse focus
warn 'mouse focus' if $app_state & SDL_APPMOUSEFOCUS
Application has keyboard focus
warn 'keyboard focus' if $app_state & SDL_APPINPUTFOCUS
Application is visible
warn 'Application Visible' if $app_state & SDL_APPACTIVE
Enable/disable joystick event polling
my $status = SDL::Events::joystick_event_state( $state );
This function is used to enable or disable joystick event processing. With joystick event processing disabled you will have to update joystick states with SDL_JoystickUpdate and read the joystick information manually. $state can be:
Joystick event handling is default. Even if joystick event processing is enabled, individual joysticks must be opened before they generate events
Warning: Calling this function may delete all events currently in SDL's event queue.
If $state is SDL_QUERY then the current state is returned, otherwise the new processing state is returned.