Re: [Tuxnes-devel] Speed?

[Jim U. <ji...@3e...>]

The list is alive!  Thought I got unsubscribed.

At 11:18am on 2001 June 27, Jon Niehof did write:
> I'm running a K6-2 500, and Final Fantasy III feels subjectively slow--
> pans are slow, etc. etc. It seems to be sustaining about 40 fps. Using
> the differential renderer, top reports 85% CPU in TuxNES and 15% in X.
> The standard X11-based renderer runs more of a 50/50 split.
On my celeron 366, with xfree86 3.3.6, it runs at about 40-50 fps, and usually
a solid 60fps using DGA.  Though I haven't tried FF3.
 
> I'm presuming, since the core engine is quite fast, that the renderer is
> the slow point here. Is this correct? And do other people sense that
> TuxNES feels slow? Would perhaps an automatic frame-skip to keep up at
> 60fps help? Or is that a hidden option somewhere?
The renderer is not the fastest thing ever.  Plus you have the overhead of
X...  I think it is possible to use DGA with X, if it is not then try
loading the ggi libraries and playing in DGA mode.  This works well for me.

I have been working on a modification to the renderer, basically to make it
playable on my dreamcast, which is also not the fastest thing ever.  The major
changes are (1) render 8 horizontal pixels per inner render loop (rather
than 1 per loop), and (2) render one line at a time, rather than partial
lines.  We lose the ability to support the color emphasis and monochrome
bits, but gain a lot of speed.  These changes, along with some modifications
to sprite rendering, have increased my speed from 20 fps to 55.  I'm
at the point where the actual CPU emulation (not using the dyn-rec engine)
uses >50% of the time, so it's worth optimizing that now.  I may backport
pixels.h to the x86 version of TuxNES to check on the speedup.

BTW, TuxNES already has an automatic frame skip.  
Look in the UpdateDisplay*() functions.

Have you tried disabling sound?  It plays jerky if I leave it on...

-- 
"There is a very hollow echo of a gaur in the birth of that animal to a cow
in Iowa.  To say that is a gaur is to disrespect all gaurs in all the places
where gaurs live.  That animal will never live its life in true gaurdom, to
wander in the forests of India and frolic with other gaurs and die and let
teak trees grow out of it.  That's the gaur I'm working to save." -K. Redford
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