[Bf-committers] debugging OpenGL/VBO's

[Campbell Barton]

today I was looking into a VBO bug that have a totally useless
backtrace in GDB. (crash inside the GL driver)

Using bugle - http://www.opengl.org/sdk/tools/BuGLe/
On Linux did the usual ./configure; make; make install

Copy doc/examples/filters into ~/.bugle/filters
 BUGLE_CHAIN=validate LD_PRELOAD=/usr/local/lib/libbugle.so  /b/blender.bin

Then instead of crashing it gives a useful message as to whats going
wrong, like this...
 [NOTICE] checks.error: illegal normal array caught in glDrawArrays
(unreadable memory); call will be ignored.

there are other options for debugging like showfps, trace, wireframe
... see ~/.bugle/filters for options.

With the "crash" filter I managed to get a valid backtrace from gdb too.
 BUGLE_CHAIN=crash LD_PRELOAD=/usr/local/lib/libbugle.so  gdb /b/blender.bin

- thought It might be useful for people looking into VBO bugs for the
first time.

-- 
- Campbell