From: Steve Fuhrman (sfuhrman++at++covad.net)
Date: 03/07/2002 09:15:44
Hi,
I'm trying to finish up a train simulator and ran into an issue with
headlights that has me baffled.
The headlight works as expected for about 56 out of 60 miles of a database
which was auto-generated from "fake" data and then tweaked with Creator.
Nothing is unique about the small section in the middle of the database
that exhibits the problem.
What is so confusing is that from one direction (trains go in forward or
reverse on the tracks) the headlight works fine, but at the same location from
the other direction the light looks "burned out".
Here's an excerpt from a webpage I put up so you could view the problem
as I would rather show 4 pictures than ramble on for 4000 more words ;-)
See http://maxoutinc.bwcsoft.com and click on "Headlight Issues" to see
the related pictures. Warning: The pictures are full-screen so those without
fast bandwidth connections should either be patient or avoid entirely.
Background information
* No flat shaded tri-strips (using PFDBLDR_MESH_LOCAL_LIGHTING)
* pfuTraversal functions already written to look for and fix "unusual"
geometry or geostates (i.e. missing material, bad/missing normals, emissive
components, etc.)
* Headlight based on libpf/C++/projective.C example
* Database built with Creator and then converted to pfb
* flt files exhibit exact same behavior as pfb files
* Database broken into "tiles" and headlight issues cross two tile
boundaries.
Hw/Sw Information
* Performer 2.5
* nVidia 2313 driver
* GeForce 3
* RedHat Linux 7.2
* 1.4 Ghz Athlon
* 1 Gb RAM
Clues, Experiments, Questions
* Copying a "good" polygon that is lit by the headlight into a portion of
the database that isn't lit by the headlight, causes that polygon to also not
be lit.
* I'm assuming that because of the above experiment and the fact that the
problem is direction based that it has something to do with the hierarchy and
the cull/draw traversal instead of a basic problem with the geosets.
* All suggestions welcome. Please send them to sfuhrman++at++maxoutinc.com
* Thanks in advance for any help.
I'll summarize and post private replies.
pfThanks,
-- ========================================================================== Steve Fuhrman ========================================================================== -- George Bernard Shaw Do not do unto others as you would that they should do unto you. Their tastes may not be the same.
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