ManualFrameSource

FrameSource that emits frames only when you ask.

Use it when testing or replaying frame timings. No timers involved.

import {
  GameLoop,
  ManualFrameSource,
} from "@jolly-pixel/loop";

const source = new ManualFrameSource();
const loop = new GameLoop({ source });

loop.start({
  fixedUpdate,
  update,
});
source.step(16);              // one 16ms frame
source.run([100, 16, 16]);    // one hitch, then two normal frames

Constructor

new ManualFrameSource(clock?: ManualClock);

Creates its own ManualClock when none is given.

Members

Member	Meaning
clock	Read-only. The ManualClock it advances.
running	Read-only. A callback is registered.
start(callback)	Registers callback and emits one frame right away, at the current clock time.
stop()	Drops the callback.
step(deltaMs = 0): number	Advances the clock, emits one frame, returns the new time. Throws Error when stopped.
run(tape): void	Calls step() for each delta. Accepts number[] or a FrameTape.

FrameTape

A named list of frame deltas, with the scheduler options it was written for.

export interface FrameTape {
  name: string;
  description: string;
  options: FrameSchedulerOptions;
  deltas: number[];  // raw frame deltas, in ms
}

The package ships no tapes. This repo's tests and demos share theirs in fixtures/scenarios.ts.

Gotchas

• start() emits a frame immediately, and the scheduler's first frame always has a zero delta. That frame renders but runs no fixed step. Count it when asserting on update calls.