SDL_GetKeyboardState bug ? Key stuck after window moved

SDL Development
1

I noticed a strange thing and wondered if it’s a SDL bug : when my app have the focus, I press a key, then while keeping this key pressend, I move the window. Now, the state for this key is always stuck to 1, and I didnt found a way to stop it.
My event code isn’t special, I just do :

int keystate = SDL_GetKeyboardState(NULL);

at the game initialization, then i retrieve the key state with keystate[code]…

2

the bug is 100% reproductible, when you keep pressing a key while moving the window, release it BEFORE you release the mouse button

3

What operating system?On Mon, Sep 12, 2016 at 2:24 PM, sgrsgsrg wrote:

the bug is 100% reproductible, when you keep pressing a key while moving
the window, release it BEFORE you release the mouse button

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4

Windows 10.

SDL2.0.4, compiled under Visual Studio 2013

I currently tested only with the left & right keys. (SDL_SCANCODE_LEFT, SDL_SCANCODE_RIGHT)

To reproduce the problem :

  • press a key
  • while keeping this key pressed, move the window with your mouse
  • release the key
  • release the mouse click to stop moving the window
    -> the key state for this key will be stuck forever

If you release the key after you stopped moving the window, the problem does not occurs

5

Some news.

The only way i found to reset a stuck key is to make the window lose then gain its focus.

This code will force focus change if a key was pressed while the window was moved, thus correcting the stucked key glitch

Code:

while (SDL_PollEvent(&e)) {
switch (e.type){
if (e.window.event == SDL_WINDOWEVENT_MOVED) {
// check if a key was already pressed
int sdl_bug = 0;
for (int i = 0; i < 7; i++){ // the 7 keyboard keys i use in my game
if (keys[i]){
sdl_bug = 1;
}
}
if (sdl_bug){ // hack
SDL_MinimizeWindow(window);
SDL_RestoreWindow(window);
}
}
}
}

Hacks are ugly, it’d be nice if some investigation could be done