Implementing a save feature scares me

[MediocreMetastasis]

This isn't a cry for help. I wanted to talk about how scary save features are. You can't just pause the game until the user wants to play the game again (Well I guess you can under extreme circumstances) so you have to find a way to save the current state to the hard drive. How do you do that? Save everything as a variable and write it to a text file.

For example, Half life 2 lets you save the game anywhere. Which means it needs to make the player's,enemies',all physic objects', projectile's position, rotation, velocity, torque, and ai state as well as ammo, current sound playing and it's current playback position all as variables just to write it to a text file.

[candycanearter07]

Pretty much everything IN programming is controlled by a variable... the issue is about saving ENOUGH to disk that you can get close enough to where you were before, and serializing/de serializing everything properly. Also, getting the variables OUT of the game can be frustrating if you have to get through encapsulation...

[Melooon]

I was recently working on a project that I knew would need a save state, but I didn't really plan for it from the start and ended up with too many variables to easily save. I ended up having to write a mini program that saves your general place in the world, and then every time you load a save it basically simulates everything that would have happened up to that point in order to populate all the variables correctly.

It sounds like a silly solution, but as long as the simulated gameplay matches the real gameplay - it works quite well and means the entire save state can be just a single number 

[MediocreMetastasis]

every time you load a save it basically simulates everything that would have happened up to that point in order to populate all the variables correctly.

If it works it works. If you can simulate everything that has happened the game must've been simple because I can't see how you can apply that to like a fps or especially a sandbox game.