@clockwork2/engine

The simulation kernel behind Clockwork 2: a fixed-step loop, deterministic maths, seeded randomness and recordings that replay to the same bits on V8, JavaScriptCore and SpiderMonkey.

It has no runtime dependencies and imports no DOM types. Everything it needs is vendored, with attribution in the repository's NOTICE.

import { Prng, runSession } from "@clockwork2/engine"
import * as dmath from "@clockwork2/engine/dmath"

A game implements eight methods and no base class: init, tick, view, snapshot, restore, score, isOver, effects. tick() takes no time delta, so a simulation cannot depend on the player's frame rate.

Math.sin, Math.pow and the rest of the transcendentals are implementation-defined, and they really do differ: Math.cos(0.1) is 0x3FEFD712F9A817C1 on JavaScriptCore and 0x3FEFD712F9A817C0 on V8. dmath ships the same function names, transcribed from fdlibm using only operations ECMAScript specifies exactly.

docs/engine.md in the repository explains the whole design from first principles.

MIT.