I’ve run into what looks like a bug with recent nvidia drivers. I have some vbos that are occasionally updated (with glReadPixels, using the pbo extension). Under windows, with driver versions 66.93 and 67.02(beta), and under linux with version 66.29, the vbos are only updated correctly if the usage flag given during creation is gl_stream_draw_arb. gl_[static|dynamic]_draw_arb cause varying weirdness, though the best I can tell is that they zero out the areas that should be updated. Under linux with version 61.77 drivers, my code works with any usage hint; only the speed is affected.
The vbo spec says “<usage> is provided as a performance hint only. The specified usage value does not constrain the actual usage pattern of the data store.” The pbo extension doesn’t mention the usage hints at all.
Has anyone else run into this?
Also, does anyone know how I can report this to NVidia without being a registered dev? I tried to register a few months ago, but I guess I wasn’t cool enough to join their club.