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WestSideRider35
12-10-2003, 06:58 AM
I am writing a flight animation in OpenGl and am running into some troubles when it is run on an Nvidia GeForce4 ti 64mb. When run on zero hardware acceleration the project works fine. With hardware acceleration turned on, some polygons dissappear altogether, while others get broken up into jagged two tone objects. Any ideas? I need the acceleration badly so that it will run at a more than mind numbing pace.

Thank You,

Rob

Honk
12-10-2003, 08:34 AM
One word: z-fighting

Set your desktop to 32 bit deapth and then request a pixel format with 24 bit z-buffer and 8 bit stencil, voilá!

If that dosent help try to adjust your near and far clipping planes.

WestSideRider35
12-10-2003, 12:57 PM
Pardon my ignorance, but how would I go about doing that? Thanks for the help!

Rob

WestSideRider35
12-10-2003, 01:14 PM
Ok, I have added a stencil buffer by calling:

glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_STENCIL);

This did help the z-fighting, however I still lose a large chunk of polygons , even in wireframe mode.

Rob

ZbuffeR
12-10-2003, 01:46 PM
Originally posted by WestSideRider35:
This did help the z-fighting, however I still lose a large chunk of polygons , even in wireframe mode.
You can see wireframe z-fighting ?? Well, either you have good eyes, or a very tesselated geometry. Maybe it is not z-fighting after all.

See there, same zbuffer precision problem with glut : http://www.opengl.org/discussion_boards/ubb/Forum2/HTML/014782.html

WestSideRider35
12-11-2003, 06:15 AM
Well no, what I meant is that the Z-fighting seems to be cured. The remaining problem is that one whole piece of my geometry disappears under harware acceleration. Like it can't be seen from any angle.

Rob

Honk
12-11-2003, 06:47 AM
Could be culling or your clipping planes.