From: christopher.g.dorosky++at++lmco.com
Date: 03/15/2000 08:10:15
Sorry for the repeat post, but I am still having trouble.
In my scene, there is a terrain node which has all of the terrain data.
There are also various 3D models.
The source data for the terrain is greyscale. The source for the models is
color.
I can apply a color LUT to the terrain data, and get good results. I do not
want to apply the LUT to the models, because colorizing a color model has
bad results.
A solution, on a single pipe system, is to set up a color-LUT, and
selectively enable and disable it.
Since all terrain is under one node, applying a pre-draw and post-draw
callback that glEnables and glDisables GL_TEXTURE_COLOR_TABLE_SGI works
fine. The idea is that before terrain is drawn, the table is turned on, and
when terrain is done, the LUT is turned off. This works great on a one pipe
system.
On a two pipe system, I have not figured out how to make the system
understand the pipe context for the LUT's.
On a previous query, I got the response: "
> Each pipe should do this in a draw callback and it will just work. The
> pipes and contexts have separate state information, the draw processes
> and callbacks will operate on the current context on each pipe. "
>
However, what I see when running on two pipes, is intermittent color-to-grey
flashing of the terrain.
The pre and post draw callbacks appear to be running on both pipes.
If I place
if (!glIsEnabled(GL_TEXTURE_COLOR_TABLE_SGI)) { printf("table was already
off!!\n"); fflush(stdout); }
in the post draw callback, I get printouts at each flash (can happen several
times a second, but usually once every several seconds).
I have not successfully told the two pipes how to use or not use the LUT
without shutting it off for the other pipe.
Has anybody else run into this?
Christopher Dorosky
Senior Electronic Systems Engineer - Real Time Simulation
Lockheed Martin Missiles and Fire Control - Dallas
christopher.g.dorosky++at++lmco.com
972-603-2349
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