Re: [hatari-devel] OS X performance problem

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

On perjantai 30 toukokuu 2014, Thomas Huth wrote:
> Hmmm, ... and according to the man-page of SDL_UpdateRects:
> 
>  It  is  adviced to call this function only once per frame, since
>  each call has some processing overhead. This is  no  restriction
>  since you can pass any number of rectangles each time.

SDL_UpdateRect() doesn't mention that:
	http://sdl.beuc.net/sdl.wiki/SDL_UpdateRect

Any idea whether OSX backend of that also does Vsync?


> So this is likely not only a problem on Mac OS X. I think we should
> somehow rework the code so that SDL_UpdateRects is only called once per
> frame. I see two possibilities:
> 
> 1) Statusbar_Update does not do the update on its own but passes a
> rectangle list to the caller so the caller can do an SDL_UpdateRects
> with all areas.
> 
> 2) Statusbar_Update does not do the update on its own but passes a flag
> to the caller whether the statusbar has been changed. If it has been
> changed, the caller simply updates the whole window instead of only
> updating the ST screen area.
> 
> Eero, what do you think? Could you maybe implement such a solution? (or
> shall I have a try?)

Sure, I can do that. It will actually simplify statusbar.c code.

Statusbar update is called from quite many places though, and some
of them don't (currently) do any screen activity themselves:
$ grep '\bStatusbar_Update\b' *.c */*.c
main.c:          Statusbar_Update(sdlscrn);
main.c:          Statusbar_Update(sdlscrn);
screen.c:                Statusbar_Update(sdlscrn);
debug/debugui.c: Statusbar_Update(sdlscrn);
falcon/hostscreen.c:     Statusbar_Update(sdlscrn);
gui-sdl/dlgScreen.c:                             Statusbar_Update(sdlscrn);
gui-sdl/dlgScreen.c:                             Statusbar_Update(sdlscrn);

So it can uglify code by spreading screen update stuff around
a bit.  Or the update function needs also an arg flag for
whether it should do the update itself.  Let's see which
looks better.


	- Eero