From: Dick Rous (dick++at++sgi.com)
Date: 09/03/2000 06:16:01
If your framerate is less than the refresh rate of your dispay (e.g. 30 vs.
60 Hz.),
the what you see are so calledmultiple images. These occur when objects have
a substantial angular velocity with respect to the eye. It is a visual
"deceiption", caused
by the snowflakes being twice rendered in the same spot, then shift to the
next position in
time, where again they are rendered twice.
You will notice the same effect when your simulation moves the eyepoint
along a road.
Thin vertical objects alongside the road seem to "double" when the angular
velocity increases.
The solution is to make your framerate equal to the refresh rate. (by
optimising your
database or/and adding gfx hardware) .:-)
Cheers,
Dick.
__________________________________________________________
Dick Rous SGI - European Technical
Support
email: dick++at++sgi.com
phone: +31-35-6423160 fax: +31-35-6423162 VNET: 955-6868
__________________________________________________________
-----Original Message-----
From: Hui Li [mailto:huili++at++mail.sc.cninfo.net]
Sent: 02 September 2000 15:02
To: info-performer++at++sgi.com
Subject: Is it because of Phase lock?
I try to simulate snow flakes on a 2 cpu onyx2.
what I do is draw the snow flakes at the draw call back. However, what i saw
on the screen
the flakes becomes doubled, each flakes seems be draw twice on it's drop
pass, when i slow
down the speed or freeze simulation, it looks
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