Jfgeyelin's dev blog

I wanted to write this post for a while. It describes a C++ technique to implement rollback in the context of multiplayer games that I feel is quite interesting and useful. The tl;dr is: don't bother serializing individual objects, just rollback all the memory. Rollback-based multiplayer I've been working on a multiplayer version of PewPew, and for reasons that are outside of the scope of this post, I chose to implement multiplayer with deterministic lockstep and rollback. The basic idea behind rollback-based multiplayer is that the inputs of players are replicated to all the players. Whenever a player receives the inputs of another player, the state of the game is rolled back to the point where the input happened and fast-forwarded back to the present so that the state shown to a player takes into account the inputs of the other players. Because history is being re-computed, some events get undone. For example, it's possible a player saw themselves taking a bonus, but aft...