Skip to content

Latest commit

 

History

History
584 lines (366 loc) · 14.1 KB

Events.pod

File metadata and controls

584 lines (366 loc) · 14.1 KB
Raw

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 ':init';
use SDL::Event;
use SDL::Events ':all';

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; 
        ...
    }
}

CONSTANTS

The constants are exported by default. You can avoid this by doing:

use SDL::Events ();

and access them directly:

SDL::Events::SDL_ACTIVEEVENT;

or by choosing the export tags below:

Export tag: ':type'

SDL_ACTIVEEVENT
SDL_KEYDOWN
SDL_KEYUP
SDL_MOUSEMOTION
SDL_MOUSEBUTTONDOWN
SDL_MOUSEBUTTONUP
SDL_JOYAXISMOTION
SDL_JOYBALLMOTION
SDL_JOYHATMOTION
SDL_JOYBUTTONDOWN
SDL_JOYBUTTONUP
SDL_QUIT
SDL_SYSWMEVENT
SDL_VIDEORESIZE
SDL_VIDEOEXPOSE
SDL_USEREVENT
SDL_NUMEVENTS

Export tag: ':mask'

SDL_EVENTMASK
SDL_ACTIVEEVENTMASK
SDL_KEYDOWNMASK
SDL_KEYUPMASK
SDL_KEYEVENTMASK
SDL_MOUSEMOTIONMASK
SDL_MOUSEBUTTONDOWNMASK
SDL_MOUSEBUTTONUPMASK
SDL_MOUSEEVENTMASK
SDL_JOYAXISMOTIONMASK
SDL_JOYBALLMOTIONMASK
SDL_JOYHATMOTIONMASK
SDL_JOYBUTTONDOWNMASK
SDL_JOYBUTTONUPMASK
SDL_JOYEVENTMASK
SDL_VIDEORESIZEMASK
SDL_VIDEOEXPOSEMASK
SDL_QUITMASK
SDL_SYSWMEVENTMASK
SDL_ALLEVENTS

Export tag: ':action'

SDL_ADDEVENT
SDL_PEEKEVENT
SDL_GETEVENT

Export tag: ':state'

SDL_QUERY
SDL_IGNORE
SDL_DISABLE / SDL_ENABLE
SDL_RELEASED / SDL_PRESSED

Export tag: ':hat'

SDL_HAT_CENTERED
SDL_HAT_UP / SDL_HAT_RIGHT / SDL_HAT_DOWN / SDL_HAT_LEFT
SDL_HAT_RIGHTUP / SDL_HAT_RIGHTDOWN / SDL_HAT_LEFTUP / SDL_HAT_LEFTDOWN

Export tag: ':app'

SDL_APPMOUSEFOCUS
SDL_APPINPUTFOCUS
SDL_APPACTIVE

Export tag: ':button'

SDL_BUTTON
SDL_BUTTON_LEFT / SDL_BUTTON_MIDDLE / SDL_BUTTON_RIGHT
SDL_BUTTON_WHEELUP / SDL_BUTTON_WHEELDOWN
SDL_BUTTON_X1 / SDL_BUTTON_X2
SDL_BUTTON_LMASK / SDL_BUTTON_MMASK / SDL_BUTTON_RMASK
SDL_BUTTON_X1MASK / SDL_BUTTON_X2MASK

Export tag: ':keysym'

SDLK_UNKNOWN
SDLK_FIRST
SDLK_BACKSPACE
SDLK_TAB
SDLK_CLEAR
SDLK_RETURN
SDLK_PAUSE
SDLK_ESCAPE
SDLK_SPACE
SDLK_EXCLAIM
SDLK_QUOTEDBL
SDLK_HASH
SDLK_DOLLAR
SDLK_AMPERSAND
SDLK_QUOTE
SDLK_LEFTPAREN / SDLK_RIGHTPAREN
SDLK_ASTERISK
SDLK_PLUS / SDLK_MINUS
SDLK_COMMA
SDLK_PERIOD
SDLK_0 .. SDLK_9
SDLK_COLON
SDLK_SEMICOLON
SDLK_LESS / SDLK_GREATER
SDLK_EQUALS
SDLK_QUESTION
SDLK_AT
SDLK_LEFTBRACKET / SDLK_RIGHTBRACKET
SDLK_SLASH / SDLK_BACKSLASH
SDLK_CARET
SDLK_UNDERSCORE
SDLK_BACKQUOTE
SDLK_a .. SDLK_z
SDLK_DELETE
SDLK_WORLD_0 .. SDLK_WORLD_95
SDLK_KP0 .. SDLK_KP9
SDLK_KP_PERIOD
SDLK_KP_DIVIDE / SDLK_KP_MULTIPLY
SDLK_KP_MINUS / SDLK_KP_PLUS
SDLK_KP_ENTER
SDLK_KP_EQUALS
SDLK_UP / SDLK_DOWN / SDLK_RIGHT / SDLK_LEFT
SDLK_INSERT
SDLK_HOME / SDLK_END
SDLK_PAGEUP / SDLK_PAGEDOWN
SDLK_F1 .. SDLK_F15
SDLK_NUMLOCK / SDLK_CAPSLOCK / SDLK_SCROLLOCK
SDLK_RSHIFT / SDLK_LSHIFT
SDLK_RCTRL  / SDLK_LCTRL
SDLK_RALT   / SDLK_LALT
SDLK_RMETA  / SDLK_LMETA
SDLK_LSUPER / SDLK_RSUPER
SDLK_MODE
SDLK_COMPOSE
SDLK_HELP
SDLK_PRINT
SDLK_SYSREQ
SDLK_BREAK
SDLK_MENU
SDLK_POWER
SDLK_EURO
SDLK_UNDO

Export tag ':keymod'

KMOD_NONE
KMOD_LSHIFT / KMOD_RSHIFT / KMOD_SHIFT
KMOD_LCTRL  / KMOD_RCTRL  / KMOD_CTRL
KMOD_LALT   / KMOD_RALT   / KMOD_ALT
KMOD_LMETA  / KMOD_RMETA  / KMOD_META
KMOD_NUM
KMOD_CAPS
KMOD_MODE
KMOD_RESERVED

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

set_event_filter

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);

PARAMETER

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 filtering SDL_QUIT the event will be filtered if it is non-intterupt call ( Window closes normally ). If it is a interrupt SDL_QUIT 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_key_state

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_mod_state

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 );

MOD VALUES

KMOD_NONE
KMOD_LSHIFT
KMOD_RSHIFT
KMOD_LCTRL
KMOD_RCTRL
KMOD_LALT
KMOD_RALT
KMOD_LMETA
KMOD_RMETA
KMOD_NUM
KMOD_CAPS
KMOD_MODE
KMOD_CTRL

same as KMOD_LCTRL|KMOD_RCTRL

KMOD_SHIFT

same as KMOD_LSHIFT|KMOD_RSHIFT

KMOD_ALT

same as KMOD_LALT|KMOD_RALT

KMOD_META

same as KMOD_LMETA|KMOD_RMETA

set_mod_state

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 );

event_state

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

STATES

SDL_IGNORE

The event of $type will be automatically dropper from the event queue and will not be filtered.

SDL_ENABLE

The event of $type will be processed normally. This is default.

SDL_QUERY

The current processing state of the $type will be returned

get_key_name

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_unicode

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).

enable_key_repeat

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.

get_mouse_state

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

get_relative_mouse_state

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

get_app_state

Gets the state of the application

my $app_state = SDL::Events::get_app_state();

The $app_state is a bitwise combination of:

SDL_APPMOUSEFOCUS

Application has mouse focus

warn 'mouse focus' if $app_state & SDL_APPMOUSEFOCUS
SDL_APPINPUTFOCUS

Application has keyboard focus

warn 'keyboard focus' if $app_state & SDL_APPINPUTFOCUS
SDL_APPACTIVE

Application is visible

warn 'Application Visible' if $app_state & SDL_APPACTIVE

joystick_event_state

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::Joystick::update and read the joystick information manually. $state can be:

SDL_QUERY
SDL_ENABLE
SDL_IGNORE

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.

SEE ALSO

SDL::Event, SDL::Video

AUTHORS

See "AUTHORS" in SDL.