Game crashes sporadically when selecting a different world about supertux

[Brockengespenst]

This seems to be related to the amount of update steps that are done between drawing a frame. I played around with the steps variable in void ScreenManager::loop_iter(). If hardcoded set to 1, I was not able to reproduce the crash. Another test with step = 16; it crashed on the first try.

[tobbi]

Potentially having get_sector() return a pointer to a sector instead of a reference could fix this issue but then we'd have to add null checks to every function calling that.

Does anyone have a better idea?

[Vankata453]

I think we should just make sure a sector is always available, since initialization. It's not supposed to not have a current sector set.

[Brockengespenst]

Maybe I found a solution. The worldmap camera is a member of WorldMapSector, so it belongs to a specific worldmap sector. When WorldMapSector::update() invokes m_camera->update(), Camera::update() calls Camera::get_camera_pos_for_tux() which uses WorldMapSector::current() that refers to the newly created WorldMap with m_sector being nullptr. Instead we could pass the WorldMapSector as argument to Camera's constructor, store it as member (reference) and replace the calls to WorldMapSector::current() with the member.
A first quick and dirty test seems to work.

But in general I agree to @Vankata453 , that having always a valid current sector would be preferrable.

[Vankata453]

@Brockengespenst Thanks for checking this out! Would you like to create a PR for this?

[Brockengespenst]

Sure, no problem. Please check #2921.