Scene Runtime Schedule And Frame Budget

Scene runtime scheduling orders scene systems and decides which phases must finish every frame versus which can be budgeted, deferred, or caught up over several frames.

Purpose

Use this page when adding a new scene runtime system, debugging stutter, or investigating why a subsystem ran later than expected.

Phase Registry

SceneRuntimePhase defines ordered phases such as load, trigger, actors, cutscene, environment, audio, graph, navigation, and persistence. Descriptor records identify each contributor and its phase.

Must-Finish Versus Budgeted Work

Some phases must finish this frame because later systems depend on them. Others can be budgeted with work units. Budgeted work may defer under frame pressure, but it must report debt so the runtime can recover.

Debt And Deferral

Frame-budget state tracks allowed phases, deferred phases, debt units, and consecutive deferrals. A system that is always deferred should reduce work, move lanes, or expose a stronger invalidation signal.

Critical Invalidations

Scene changes, cutscene actor resolution, asset reloads, and authority transitions can force normally budgeted work to run. Use critical invalidations sparingly; they are a correctness tool, not a performance escape hatch.

Telemetry And Debugging

Runtime performance telemetry should name slow contributor phases and deferred phases. Debug overlays should show whether a missing update is a schedule issue or a system logic issue.

Integration Checklist

Choose a phase, decide budget policy, register a descriptor, add tests for ordering, add telemetry labels, and document whether the system may defer under pressure.