And ... I'm back in the game. Took a little break over Christmas and the neglect caused Spooky Pooky to get very cross with me.

Fired it up and randomly fullscreen was running at about 30fps.

No idea why - MacBookPro retina using GLFW and OGL 3.2. Windowed still worked fine, even a window the same size as fullscreen.

So began a long and ultimately fruitless journey to try and work what the hell was happening. Over Christmas I'd done two things that I thought could be relevant. The first was that I played quite a bit of Elite Dangerous, in full screen. The second was that I plugged my laptop into my Sony TV via HDMI.

Still not understanding the problem I switched the window + context creation code to use SFML (since I was planning to do that anyway) with no discernible difference. Finally I switched vsync off and suddenly it was running at full speed again (actually ridiculous speed, since I'd artificially set delta times to 1/60s to help with debug pauses, so it was blasting along at 7 billion fps).

Anyway, none the wiser really.

Since then I've bypassed the SFML fullscreen mode when running on macs to make the game compatible with OS X fullscreen stuff, meaning I don't have to deal with context recreation (a pain since context sharing doesn't work on OS X with the OGL version I use).

Brilliant. Anyway, mapping the input over to use SFML was trivial so the game is back to running how it should and I can get on with fixing the room transition code.

Originally the game was being written as a level-based thingy - now it's a metroidvania. So levels have become rooms, and it lets you randomly wander between them. It's been fairly easy to transition the game to this. Each room is a Tiled map and I cache them in memory, preserving entity state as you wander between them.

Rooms can be grouped into sections so I may flush whole sections out of memory when you cross the boundary - either way it's a fairly lazy system.