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View Full Version : List/strips disappear when rendering to BMP



John Bunk
04-19-2001, 10:55 AM
I'm going nuts trying to solve this problem. I render polygons, spheres, lines, as well as glNewList's of triangle strips (terrain) with textures. When I render to the screen, everything shows up. When I render to an offscreen bitmap, everything renders EXCEPT for the display list / triangle strips! At first, I thought this was a lighting problem, and have tweeked the material / lighting parameters (including emissions!), yet nothing. Oh yes, I'm using Win98(original) and have a nVidia GForce2 MX card. Any ideas?

Thanks
John

Deiussum
04-19-2001, 11:08 AM
When you render to the bitmap when do you create the display list you are trying to render? Before or after you initialise an OpenGL context? Sounds like it may be getting done before OpenGL is initialised, which will cause it not to be created since you cannot succesfully use OpenGL commands before it is initialised.

Korval
04-19-2001, 11:56 AM
If I understand correctly, you are creating a new rendering context for drawing to bitmaps, but the display lists were setup in the old RC. Since RCs do not normally share display lists, you will need to use the function wglShareLists to share display lists between the RCs.

John Bunk
04-19-2001, 04:09 PM
To all,
Thanks for the input, as this was the problem! For the moment, I just took the cheap / low road and regenerated the lists after the wglMakeCurrent and right before rendering on the internal bitmap. Bingo, the lists appeared on the BMP file! I'll try the wglShareLists later so things will speed up a bit I hope.

Thank you!
John