C SDL Keyboard Events SDL_KEYUP Triggering When Key Is Down - c

Question

I am using SDL in C, and I'm trying to make a character move on the screen when a key is pressed, and stop when it is released, but it seems as if the KEYUP event is triggering when the key is still being held down. If I remove the KEYUP section in pressed(), the characters will slide across the screen, but obviously won't stop on their own. If I leave the KEYUP section in, I have to press the key repeatedly to move them across the screen.
Any idea what I'm doing wrong?
Here's what I have:
...
int done = 0;
while (done==0)
{
pressed();
if (kenter == 1)
{
state = 1;
subscreen();
}
if (kescape == 1)
{
done = 1;
}
if (kup == 1)
{
playery += -2;
}
if (kdown == 1)
{
playery += 2;
}
if (kright == 1)
{
playerx += 2;
}
if (kleft == 1)
{
playerx += - 2;
}
...
int pressed ()
{
SDL_Event keyevent;
while (SDL_PollEvent(&keyevent))
{
switch(keyevent.type)
{
case SDL_KEYDOWN:
switch(keyevent.key.keysym.sym)
{
case SDLK_RETURN:
{
kenter = 1;
break;
}
case SDLK_ESCAPE:
{
kescape = 1;
break;
}
case SDLK_a:
{
ka = 1;
break;
}
case SDLK_s:
{
ks = 1;
break;
}
case SDLK_UP:
{
kup = 1;
break;
}
case SDLK_DOWN:
{
kdown = 1;
break;
}
case SDLK_RIGHT:
{
kright = 1;
break;
}
case SDLK_LEFT:
{
kleft = 1;
break;
}
default:
break;
}
}
switch(keyevent.type)
{
case SDL_KEYUP:
switch(keyevent.key.keysym.sym)
{
case SDLK_RETURN:
{
kenter = 0;
break;
}
case SDLK_ESCAPE:
{
kescape = 0;
break;
}
case SDLK_a:
{
ka = 0;
break;
}
case SDLK_s:
{
ks = 0;
break;
}
case SDLK_UP:
{
kup = 0;
break;
}
case SDLK_DOWN:
{
kdown = 0;
break;
}
case SDLK_RIGHT:
{
kright = 0;
break;
}
case SDLK_LEFT:
{
kleft = 0;
break;
}
default:
break;
}
}
}
return 0;
}

Answer 1

I think your switch statements are broken.
Use this less confusing way
int pressed ()
{
SDL_Event event;
while(SDL_PollEvent(&event) )
{
if(event.type == SDLK_KEYDOWN)
{
switch(event.key.keysym.sym)
{
case SDLK_RETURN:
doStuff = 1
break;
default:
break;
}
}
if(event.type == SDLK_KEYUP)
{
switch(event.key.keysym.sym)
{
case SDLK_RETURN:
doStuff = 0;
break;
default:
break;
}
}
}
}
Also important:
SDL Tutorials: Practical Keyboard Input
Oh and avoid using global variables!

Answer 2

Your use of two switch statements is odd and confusing, you should probably fix that.
The issues you're seeing are likely due to keyboard repeat, see the SDL_EnableKeyRepeat() call for how to disable it.

Answer 3

don't use switch. I experienced same thing, but I resolved into using 'if' like this. Maybe switch has 'else if'.
if(event.type == SDL_KEYDOWN){
....
}
if(event.type == SDL_KEYUP){
....
}