how would i do something a key is lifted in SDL?

[jimi_hendrix]

tell me if you want my source but lets say i read the key input and then go to a switch statement where i read the event and then do something per key...how would i do something until that key is lifted...

[Lux Perpetua]

The relevant information is here:

http://www.libsdl.org/cgi/docwiki.cgi/Introduction_to_Events
http://www.libsdl.org/cgi/docwiki.cgi/SDL_KeyboardEvent

You can check for SDL_KEYUP to figure out if the key has been lifted.

By the way, SDL has great documentation:

http://www.libsdl.org/cgi/docwiki.cgi/SDL_API

[jimi_hendrix]

thanks

[jimi_hendrix]

ok that stuff didnt really help but why is this code wrong
void handleInput()
{
bool keepGoing = true;
while (keepGoing == true)
{
keepGoing = false;

//get the keystate and begin checking for keydowns
Uint8* Keys = SDL_GetKeyState(NULL);

if(Keys[SDLK_LEFT])
{
x -= velX;
keepGoing = true;
}

if(Keys[SDLK_RIGHT])
{
x += velX;
keepGoing = true;
}
}
}

[jimi_hendrix]

it just hangs

[jimi_hendrix]

bump

[raf_kig]

SDL_GetKeyState:
Gets a snapshot of the current keyboard state. The current state is returned as a pointer to an array. The size of this array is stored in numkeys. The array is indexed by the SDLK_* symbols (see SDLKey). A value of 1 means that the key is pressed and a value of 0 means that it is not. The pointer returned is a pointer to an internal SDL array. It will be valid for the whole lifetime of the application and should not be freed by the caller.

Note: Use SDL_PumpEvents to update the state array.
I suggest reading http://www.libsdl.org/cgi/docwiki.cgi/SDL_GetKeyState before using the function ;-)

Regards

raf

[jimi_hendrix]

ill try it later and tell if it works

[slavik]

oldie but goodie? those were the days ...

http://ubuntuforums.org/showthread.php?t=490914

[jimi_hendrix]

looked at the code where you handled input and couldnt figure out how you did it...but i have a break coming up so i will have plenty of time to figure this out

[slavik]

yeah, that's the bad part of the code :(

the idea is that the keysym returns an array where 1 is the key is pressed and 0 the key being unpressed (the key is an index in the array). what you want to do is act while the key is pressed. grabbing the keysym happens every iteration.

[jimi_hendrix]

right...i can make my ship move when the player hits a key...but if they hold the key down it stands still until they pick their finger up and press the key again...i want it to keep on moving

[slavik]

my code does that, compile it ;)
look carefully at the bodies of the if statements.

[jimi_hendrix]

i know...im trying to figure out how it does that ;)