I've made a system which uses the ideas from "Fix your Time Step" in order update physics. I'm having trouble finding standard methods for dealing with this when user input affects player movement outside of a time-step.
If we want to integrate player movement within the "fixed time step, variable fps" system, I guess I would have to queue up player actions somehow, when accumulation hasn't yet completed. But then how do I integrate several different player actions within said timestep? IE lets say within timestep of N milliseconds, the player executes a move forward, move right and move backwards, where there is an infinite collidable wall in front.
I could always calculate the last input, but in this case, it wouldn't be correct to do so. The player actually should be blocked by the wall, and then moving right and back would move them to the right, and back, to the right of where only processing the last input would lead.
Similarly, if all movement was accounted for together, it might result in a player having an impossible vector for the final position, but if all moves were taken independently, there might have been a valid path (ie around a corner).
If I process all inputs then the player made during the time-step, it could conceivably be costly if they made a million tiny movements (collision check at each movement), though with exact physics (as far as a fixed time step simulation is concerned).
Even if we thought the last bullet wasn't that bad, as soon as you add multiple players to the equation, it starts looking really bad, especially with a server.
Are my only options to process all actions or only process a subset of them?