From: "Eric Botcazou" <ebotcazou AT libertysurf DOT fr>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: [OT] Allegro keyboard handling
Date: Mon, 28 May 2001 13:49:53 +0200
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> if (keypressed()) {
>    if (key[KEY_LEFT])  --mycircle.x;/*move it left*/
>    ...
>    if (key[KEY_ESC]) break;/*exit from loop*/
> }

The problem lies in this loop that begins with keypressed().
keypressed() returns TRUE if keypresses are waiting in the buffer and it can
of course detect autorepeat.
But: autorepeat works with the *last* pressed key only. That is, when the
first key is being held down, Allegro generates autorepeat for it hence
keypressed() return TRUE and it works. Now, if you press another key then
release it, Allegro doesn't generate autorepeat for the first key any
longer, because it is not the last pressed key, and keypressed() return
FALSE.

The solution is to get rid of keypressed():

while (!key[KEY_ESC]) {
   if (circle_has_moved)
      circlefill(screen,mycircle.x,mycircle.y,mycircle.r,mycircle.c);
   if (key[KEY_LEFT])  --mycircle.x;/*move it left*/
   if (key[KEY_RIGHT]) ++mycircle.x;/*move it right*/
   if (key[KEY_UP])    --mycircle.y;/*move it up*/
   if (key[KEY_DOWN])  ++mycircle.y;/*move it down*/
   if (key[KEY_EQUALS])++mycircle.r;/*plus sign makes it bigger*/
   if (key[KEY_MINUS]) --mycircle.r;/*minus sign... makes it smaller*/
   if (key[KEY_ENTER]) ++mycircle.c;/*enter changes color*/
}

As a general rule, try to avoid mixing buffered key input (keypressed(),
readkey(), clear_keybuf) and the key[] array in a loop.

--
Eric Botcazou
ebotcazou AT multimania DOT com