Re: [Algorithms] FPS Questions

[Stephen J B. <sj...@li...>]

On Wed, 2 Aug 2000, Stephen J Baker wrote:

> On Wed, 2 Aug 2000, gl wrote:
> 
> > > > executable) that perfectly demonstrate why accumlation buffer blur is
> > >
> > > you can use a accumulation buffer (or t buffer) to do proper motion
> > blur...
> > > there's nothing that prevents you from using it to do the averaging of the
> > > multiple frames for each displayed frame, and that's probibly the best way
> > > to go about it.
> > 
> > Good point.  But then of course you need to supersample the framerate.
> > Which brings us neatly back to why we need higher fps in the first place.
> 
> Well, strictly, you should still use motion blur even at 60Hz or higher
> because motion blur is really just *temporal* antialiasing.  The
> canonical example is that even on 60Hz systems, a rapidly spinning wheel
> will appear to slow down or run backwards when it revolves at speeds
> higher than 60Hz (or 60Hz divided by the rotational symmetry of the
              ^^^^^^^^^^^^^
          Ooops!  That should be 30Hz.
          *Half* the frame rate.

> wheel).  Motion blur is the way to fix that - and in theory, you always
> need it in any system that has a discreet 'frame rate'.

Steve Baker                      (817)619-2657 (Vox/Vox-Mail)
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