From: ihawkes2++at++csc.com.au
Date: 04/25/2001 16:06:07
Hi,
I am doing some work involving projected textures and I have noticed that
at certain eyepoint positions, the second pass fails to draw anything
except lightpoints. The vast majority of eyepoint positions work fine, but
the problem occurs reliably at certain spots. There doesn't seem to be
anything unusual in the scene at these spots that might be causing the
strange behaviour. Moving the eyepoint fractionally away from the problem
spots causes the problem to go away.
In an effort to isolate the problem, I disabled my projected texture code
and put the following code into the draw callback:
pfDraw();
glClearDepth( 1.0 );
glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
glClear( GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT );
pfDrawScene();
This resulted in the same problem occurring at the same eyepoint positions
(ie no geometry except light points appearing in the scene at the problem
spots). Using ogldebug32, it is apparent that the scene gets rendered
normally on the first pass and then the display list is empty except for
light points on the second pass.
The problem goes away if PFCULL_VIEW is not set (ie no culling). The
problem also goes away if I disable cliptextures (a virtual cliptexture
with pre-cull callbacks to set cliptexture tile parameters and
PFN_CULL_SORT_CONTAINED set).
Can anyone think of any reason that the display list might be getting
cleared (or draw bins getting emptied??) after the first pass?
I am using Irix 6.5.8f and Performer 2.4 on an Onyx2 IR.
Thanks,
Ian Hawkes
CSC Australia
This archive was generated by hypermail 2b29 : Wed Apr 25 2001 - 17:16:37 PDT