Kenneth B Russell (kbrussel++at++media.mit.edu)
Tue, 7 Apr 1998 16:05:16 GMT
We'd love to use shadowed lights in our Performer 2.2
application. However, just trying out the "shadows" example in
/usr/share/Performer/src/pguide/libpf/C/shadows.c verbatim, we
run into two problems:
1. Moire effects at polygon edges
2. Glitches in the shadow itself (only seems to happen with
certain pieces of geometry)
I thought the first of these effects might be the "self
shadowing" problem mentioned in the man pages; however, playing
with the PFLS_SHADOW_DISPLACE_SCALE and
PFLS_SHADOW_DISPLACE_OFFSET parameters results in something that
looks wrong (the part of the shadow which should appear on the
geometry seems to "slide off"), and the moire is still visible.
I've illustrated these problems in the following images:
http://www.media.mit.edu/~kbrussel/shadow0.jpg
http://www.media.mit.edu/~kbrussel/shadow1.jpg
http://www.media.mit.edu/~kbrussel/shadow2.jpg
Could someone who is using shadowed lights please take a quick
look and tell me whether or not this is normal behavior?
This is on an Onyx2 with iR graphics, but not the latest patch
set; the latest graphics patch we have is 2326. It doesn't look
like graphics rollup #4 addressed this, though.
Thanks very much,
-Ken
__________________________________________________________________________
Kenneth B. Russell Synthetic Characters Group, MIT Media Lab
kbrussel++at++media.mit.edu http://www.media.mit.edu/~kbrussel
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