Abstract
A method for simulations that must agree bit for bit on every machine. Time is a signed 64-bit count of 1/480-second steps from a fixed UTC instant, plus an 11-bit fraction for drawing at the display's predicted time, and is never accumulated from frame times. Every periodic motion has a whole number of cycles in a period of 2^21 steps, so its phase is a single wrapping 32-bit multiplication that is exact on every CPU and GPU. Sine, cosine, exponentials, logarithms and square roots use fixed-point arithmetic and tables from one integer-only generator, with CPU and GPU implementations tested for identical bits. A network mode sends a motion law's kind, parameters, start step and seed once, so every machine evaluates the same bits instead of receiving streamed states; non-player characters travel as intents and breaks as commands. Results are sorted into three determinism layers (gameplay, shared integer forms, cosmetic), and a world stores laws, seeds, recipes and causes instead of sampled states.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Kimberlin, Kyle, "Exact Integer Time, Whole-Number Phases and a Network Mode that Sends Laws of Motion", Technical Disclosure Commons, ()
https://www.tdcommons.org/dpubs_series/12435