FrameSource

Supplies frame timestamps to a GameLoop.

Pick a source

Source	Use it for
RequestAnimationFrameSource	Browsers. The GameLoop default.
AnimationLoopFrameSource	Renderers with setAnimationLoop(), such as three.js or WebXR.
ManualFrameSource	Tests and replays. You decide when frames happen.

Interface

Implement it to plug in your own frame pump.

export type FrameCallback = (
  now: number
) => void;

export interface FrameSource {
  start(
    callback: FrameCallback
  ): void;
  stop(): void;
}

Rules for an implementation:

• now is in milliseconds, on whatever timebase the source uses.
• start() may call callback synchronously.
• Calling start() again replaces the previous callback. Never leak it.

IMPORTANT

Never skip frames to cap the frame rate. Skipped frames hide their time from the scheduler, so a 30fps cap built this way runs fixed steps in pairs. Cap with maxFps instead.