[GRASS-dev] [bug #4493] (grass) gis.m fails to start GUI

[Glynn Clements]

Michael Barton wrote:

> I think that Glynn is fixing (or maybe has fixed) NVIZ.

Nope. All I've done to NVIZ is to update Togl to 1.7 (which is
supposed to include native Mac support, although I'm not sure whether
it's functional).

If the issues with (some versions of) Tk 8.4 and NVIZ are down to the
use threads in those versions of Tk, it may simply not be possible to
use those versions with NVIZ.

Essentially, if Tk is trying to use threads "transparently", using
OpenGL simply won't work.

OpenGL stores the GLX context in thread-specific storage, so that you
can safely use OpenGL concurrently from multiple threads. Before you
can use OpenGL from a given thread, you have to bind a GLX context in
that particular thread. If the Tcl run-time treats all threads as
equal and executes code in whichever thread it feels like, the
application will end trying to use OpenGL calls without a valid GLX
context having been bound.

-- 
Glynn Clements <glynn at gclements.plus.com>