Re: suggestion: replay backward/forward
Posted: 27 Jan 2019, 04:15
heh, I was still thinking RNGs were made by requesting the last digits of clock time.PicassoCT wrote: ↑20 Jan 2019, 09:43There are no real random numbers in computation? unless you have external sensors too non deterministic real world data. And as the sim has to be sync aka the same after all input steps on all computers, random has to be the same for machines. Spring uses the Mersene Twiste for random, and although the results are slightly biased due to luas number range skewing the outcome its overall a very good random.
No, why does spring not have backwards replay ability and why do lots of other commercial engine do not have that as well or just some approximation like jump to replaysafe point at fixed time XY (like Halo 1 Engine).
Because the replay does not contain what happened in the game. It only contains all input.
Your replay for a deterministic simulation engine only contains all inputs, be it chat, mouse movements and keyboard inputs. If used with the same engine and the same game, the input can replay the game. Replay as in fast forward all input steps and simulation to the point in time the player wants. To speed that up, you can create subsavegames, as in points in time from where to start from. But let's say you want to actually reverse the flow of time. How to do that? Because that would make it necessary to really save all that happened since last input and then inversing them chronological.
And that one is hard.
Real hard as in a lot of game engines for money don't do that, cause so little is gained by it. Sometimes people don't do simple stuff not because they are lazy or evil. They don't do it because you demand water to flow up the river.