Crash on exit about libfive

[mkeeter]

Can you see if 48f58c5 helps?

[nickodell]

Fix confirmed.

[mkeeter]

Did this just start happening in that revision? If you go back to 9d57a23, does it still crash?

Does this only happen when rendering is still in progress when you quit?

This was to fix a crash that I was noticing where if you quit while a render task was still in progress, it would hold off on deleting the Shape until after the OpenGL context was destroyed, so it would crash when it tried to delete the buffers, etc.

[nickodell]

9d57a2 still crashes, with both kinds of errors. I think it segfaults more.

[nickodell]

There is definitely a connection between rendering and the crash. It crashed 5 out of 5 times when I interrupted the render, and 0 out of 5 when I didn't.

Opening and closing an empty file doesn't trigger it either.