[SDL] sensible optimization [was re: tile based _junk_]

ben.campbell at cyberlife.co.uk ben.campbell at cyberlife.co.uk
Fri Aug 20 08:39:49 PDT 1999

> > It certainly makes more sense saying 20 fps is playable 
> framerate than declaring engine
> > to be able to run at anything >30 fps, without mentioning 
> that >30 framerates are
> > unnoticable by human eye (like most game companies do these 
> days....). In fact even 15fps
> > is good enough if it is *consistent* framerate. Most videos 
> are encoded at 15fps and are
> > smooth enough.
> > Vasek
> Well, Movies run at 24 frames per second or so and you can't 
> even tell the difference
> between them and real life, so I would say that 20 is 
> entirely playabe. I guess I come from
> programming databases then huh.  Well I guess George Lucas, 
> Steven Speilberg, James Cameron
> and the like all come from database work too.

As much as I didn't want to get drawn into this debate :-) I have to say I
think this is wrong. Games running at the full refresh rate of the display
generally _do_ look a lot smoother. The old
"but-the-human-eye-only-needs-12-frames-per-second" argument just isn't

Ideally, you want to have the display redraw rate decoupled from your game
logic. The game logic should try and run at constant speed on any machine,
but the display should increase its rate to go as fast as the processor
power will allow.
Of course you set a limited at the video hardware refresh rate - no point
drawing frames the user will never see.

We had the NVidia games-company-liason guy for the UK visit us a while back,
and he recommended that you should be aiming at high-end of 100Hz (!) as
that is the sort of refresh rate the new generation of video cards (eg TNT3)
support. Personally, I think that 100Hz is somewhat overkill (although he
claimed he was running his desktop at the rate), but on the other hand I
think that limiting your games to 24 fps is selling yourself way short.

Sorry - nothing about SDL in this post :-(

Ben Campbell (Antipodean Straggler)
Programmer, CyberLife Technology Ltd
ben.campbell at cyberlife.co.uk

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