Loop architecture

FrameScheduler turns frame timestamps into fixed steps and a render decision. GameLoop connects it to a frame source and calls the host's callbacks.

A host with its own frame pump skips FrameSource and GameLoop and calls advance() itself.

Frame sources

Sources only supply timestamps. They never cap the frame rate.

Source	Frames come from	Use for
RequestAnimationFrameSource	requestAnimationFrame	browsers, the default
AnimationLoopFrameSource	a renderer's setAnimationLoop()	renderers that own the frame pump
ManualFrameSource	step() and run() on a ManualClock	tests and replays

Utilities

None of these are required by the core.

Utility	Where it plugs in
Interpolated	push a sample after each fixedUpdate, read at(alpha) in update
FrameBudget	a deadline for optional work inside a frame, timed by a Clock
FrameRateGovernor	reads each FrameSchedule from frame, sets scheduler.maxFps
suspendWhenHidden	stops and restarts a GameLoop as its element leaves and enters view
Clock	time for FrameBudget and ManualFrameSource

One frame

Case	FrameSchedule	GameLoop
First advance()	zero delta, render: true	calls update only
Long gap	clamped: true	emits clamp
Overload	panicked: true, droppedMs	emits panic
maxFps cap	render: false	still runs fixed steps
Paused	effective timeScale is 0	keeps receiving and rendering frames

The lag policy explains why excess time is dropped.

Lifecycle

A sleeping loop stops its source until invalidate() wakes it. Pausing is a separate flag and does not change these states.

See the API section and the glossary for details.