A thread import problem

Dieter Maurer dieter at handshake.de
Sat Jul 21 10:32:09 CEST 2012

Bruce Sherwood <bruce.sherwood at gmail.com> writes:
> ...
> from visual import box, rate
> b = box()
> while True:
>     rate(100) # no more than 100 iterations per second
>     b.pos.x += .01
> This works because a GUI environment is invoked by the visual module
> in a secondary thread (written mainly in C++, connected to Python by
> Boost). The OpenGL rendering of the box in its current position is
> driven by a 30-millisecond timer. This works fine with any environment
> other than Mac Cocoa.
> However, the Mac Cocoa GUI environment and interact loop are required
> to be the primary thread, so the challenge is to have the visual
> module set up the Cocoa environment, with the user's program running
> in a secondary thread. Any ideas?

The usual approach to this situation is to invoke the user code via
a callback from the UI main loop or invoke it explicitely
after the UI system has been set up immediately before its main loop
is called. Might look somehow like this:

main thread:

from thread import start_new_thread
from visual import setup_gui, start_main_loop
setup_gui() # sets up the GUI subsystem
start_new_thread(lambda: __import__(<your module>), ())

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