Debugging Tips
Normally Mesa (and OpenGL) records but does not notify the user of
errors. It is up to the application to call
glGetError
to check for errors. Mesa supports an
environment variable, MESA_DEBUG, to help with debugging. If
MESA_DEBUG is defined, a message will be printed to stdout whenever
an error occurs.
More extensive error checking is done in DEBUG builds
(--buildtype debug
for meson, build=debug
for scons).
In your debugger you can set a breakpoint in _mesa_error() to trap Mesa errors.
There is a display list printing/debugging facility. See the end of src/dlist.c for details.