Re: [AL] bug hunting

[Fabio S. <fab...@ne...>]

At 13:30 27/11/2003 +0100, you wrote:
>Fabio Stange wrote:
>
> > {
> >    /* Now all you did to that memory bitmap goes into the
> >       screen all at once, no noise, no flicker */
> >    blit (...) // my_screen -> screen
> >    my_screen =3D screen;
> >    destroy_bitmap (my_screen);
> > }
>
>Err, if I understand correctly you just did a
>"destroy_bitmap(screen)", effectively. That's definitely not good
>practice: screen is a video bitmap, and you're not supposed to touch
>it! You just draw to it. (Correct me if I'm wrong.)

Ops. You are right.
I didn=B4t have my own code to post here, so this popped out of my head and=
=20
went wrong.
But that could be easilly corrected with:
{
    BITMAP *tmp;
    /* Now all you did to that memory bitmap goes into the
      screen all at once, no noise, no flicker */
    blit (...) // my_screen -> screen
    tmp =3D my_screen
    my_screen =3D screen;
    destroy_bitmap (tmp);
}
And the idea remains the same.
I like to use these functions because it seems to simplify a lot to me. All=
=20
my other functions remain untouched, and I don=B4t need to worry where I=B4m=
=20
writing to.


>The standard practice would be to
>
>BITMAP *buffer =3D create_bitmap(SCREEN_W, SCREEN_H); (or smaller, if
>                                                      you have a large
>                                                      virtual screen)
>while (1)   // gameloop
>{
>         clear_to_color(buffer, makecol(0,0,0));
>
>         // draw something on buffer
>
>         blit(buffer, screen, ...);  // blit buffer to screen
>}
>
>
>That way you don't have to touch the screen bitmap at all.
>
>Hein Zelle
>
>
> >-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=
=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-<
>  Unix is user friendly. It's just very particular about who
>  it's friends are.
>
>  Hein Zelle                     he...@ic...
>                                 http://www.icce.rug.nl/~hein
> >-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=
=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-=3D-<
>
>
>-------------------------------------------------------
>This SF.net email is sponsored by: SF.net Giveback Program.
>Does SourceForge.net help you be more productive?  Does it
>help you create better code?  SHARE THE LOVE, and help us help
>YOU!  Click Here: http://sourceforge.net/donate/
>--
>https://lists.sourceforge.net/lists/listinfo/alleg-main