Steve Baker (steve++at++mred.bgm.link.com)
Wed, 19 Feb 97 08:29:51 -0500
This means that polygons end up having curved edges and texture patterns also
need to be applied on a curve.
Some IG's try to kludge this by dynamically splitting polygons into smaller
chunks so that those curved edges are approximated by straight lines. This
works to some degree - but can cause problems with texture mapping.
The only way that I know to attempt distortion correction on an SGI is
to render the scene to an off-screen area, then to suck the resulting image
into texture memory and use that to texture a set of polygons that approximate
the inverse of the surface that you are trying to correct for.
This obviously takes a significant amount of time.
That approach is OK for fairly mild distortions - but for drastic ones you
can suffer from a lack of pixel resolution in some areas of the screen - and
an excess of resolution (which will cause aliasing) in others.
There are also external hardware boxes that take raw analog video and do a
similar job (with presumably similar results - but without slowing the
SGI box down).
Steve Baker 817-619-1361 (Vox-Lab)
Hughes Training Inc. 817-619-8776 (Vox-Office/Vox-Mail)
2200 Arlington Downs Road 817-619-4028 (Fax)
Arlington, Texas. TX 76005-6171 Steve++at++MrEd.bgm.link.com (eMail)
http://www.hti.com (external) http://MrEd.bgm.link.com/staff/steve (intranet)
http://web2.airmail.net/sjbaker1 (external)
"You can't destroy the Earth - that's where I keep all my stuff!" - The Tick.
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