4 ms·
> This is perfectly appropriate in many settings, but _especially_ video games where such deterministic results are completely irrelevant. I'm not sure I'd agr
by aw1621107 2y ago
> This is perfectly appropriate in many settings, but _especially_ video games where such deterministic results are completely irrelevant.
I'm not sure I'd agree. Off the top of my head, a potentially significant benefit to deterministic floating-point is allowing you to send updates/inputs instead of world state in multiplayer games, which could be a substantial improvement in network traffic demand. It would also allow for smaller/simpler cross-machine/platform replays, though I don't know how much that feature is desired in comparison.
- comex 2y agoIndeed, but this isn't hypothetical. A large fraction of multiplayer games operate by sending inputs and requiring the simulation to be deterministic. (Some of those are single-platform or lack cross-play support, and thus only need consistency between different machines running the same build. That makes compiler optimizations less of an issue. However, some do support cross-play, and thus need consistency between different builds – using different compilers – of the same source code.)
- nickelpro 2y agoThe existence of situations where the optimization is not appropriate, such as multiplayer input replay, does not invalidate the many situations where it is appropriate.
- aw1621107 2y agoSure, but I'm not sure anyone is trying to argue that -ffast-math is never appropriate. I was just trying to point out that your original claim that deterministic floating point is "completely irrelevant" to games was too strong.