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microscope-cockpit / cockpit

Cockpit is a microscope graphical user interface. It is a flexible and easy to extend platform aimed at life scientists using bespoke microscopes.
https://microscope-cockpit.org
GNU General Public License v3.0
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Fix texture issues #788

Closed thomasmfish closed 2 years ago

thomasmfish commented 2 years ago

This is the call that is causing the issues with the mosaic, though I'm not clear about why.

From what I can tell, there's no need to use glDeleteTextures on window close as textures that are exclusive to a context are automatically deleted with the context anyway. I'm assuming the frequent (but inconsistent) mosaic issues are due to timing often causing duplicate calls to glDeleteTextures, causing some break in OpenGL. As the mosaic would be the next obvious OpenGL update, that's where I noticed an issue. That could also explain why it often worked better the first time I ran Cockpit after checking out a different commit, as the pycache wouldn't have been updated, slowing down the call.

Closes #787

thomasmfish commented 2 years ago

One other option that may be preferable is to change all Destroys to Close(True)s, then capture EVT_CLOSE instead of EVT_WINDOW_DESTROY, as EVT_CLOSE is before the window is destroyed, so should avoid any timing issues when it comes to deleting GL textures. Would that be preferable to allowing PyOpenGL to handle the deletion automatically?

iandobbie commented 2 years ago

Another option is using the run in main thread decorator (sorry I can't remember exactly what it is called) which a lot of the openGL stuff actually uses to prevent thread classes, although if the destroy isn't needed then definitely a better plan to remove it.

thomasmfish commented 2 years ago

From what I can see, when the context is deleted, anything that's exclusively assigned to it is also deleted. That does rely on Python to garbage collect though, so it's no bad thing to manually do it (unless there is a conflict like this). I can give the main thread a go and see if that fixes it.

thomasmfish commented 2 years ago

That doesn't fix it, not sure what is going on in that case. Using EVT_CLOSE also doesn't help. For whatever reason, glDeleteTextures in freetype.py just breaks things.

iandobbie commented 2 years ago

Just played with this with the the simulation mode on my mac and it seems to solve the issues. Does this work for you and should I just pull it?