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Sequencer Event Tracks

timeline frame, time seconds, payload tag, payload text, payload float, fire-once flag, and authority flag.

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This document records the TODOS.phase-72.72.15.1.7 cinematic sequencer event track contract. Event tracks bind gameplay event triggers to timeline frames so cinematics can trigger explosion cues, open doors, start rain, and dispatch other scripted gameplay events.

Runtime Ownership#

  • Runtime module: V2Cinematics
  • Event trigger spec: FV2SequencerEventTriggerSpec
  • Event invocation row: FV2SequencerEventInvocation
  • Track evaluation: FV2SequencerEventTrackEvaluation
  • Issue enum: EV2SequencerEventTrackIssueType
  • Issue struct: FV2SequencerEventTrackIssue
  • Automation: V2.Cinematics.Sequencer.EventTracks
  • CI checker: V2/ue/Tools/check-v2-sequencer-event-tracks.py

Trigger Model#

FV2SequencerEventTriggerSpec stores a stable event id, gameplay event name, timeline frame, time seconds, payload tag, payload text, payload float, fire-once flag, and authority flag. It exposes helpers for validation and frame-crossing dispatch, so large timeline jumps still fire events whose timestamps were crossed.

FV2SequencerTrackSpec now carries EventTriggers for EV2SequencerTrackType::Event tracks. This keeps dedicated gameplay events in the same sequencer track model while preserving the older keyframe-based event fixture used by data-model and interpolation tests.

Default Fixture#

BuildDefaultSequencerEventTrack creates Track.Event.CouncilTrial.StageControl, bound to Binding.Global.Cinematic. The track contains:

  • Event.CouncilTrial.TriggerExplosion at frame 45, dispatching GameplayEvent.Cinematic.TriggerExplosion with Payload.Arena.LeftPyro.
  • Event.CouncilTrial.OpenCouncilDoor at frame 90, dispatching GameplayEvent.Cinematic.OpenDoor with Payload.Door.CouncilChamber.
  • Event.CouncilTrial.StartRain at frame 135, dispatching GameplayEvent.Cinematic.StartRain with Payload.Weather.Rain and payload float 0.65.

Evaluation#

EvaluateSequencerEventTrack validates event-track type, binding id, trigger inventory, event ids, gameplay event names, non-negative timestamps, and duplicate event ids. At a frame it returns triggered event invocation rows when the timeline lands on or crosses an event frame. Each invocation carries the event id, gameplay event name, payload fields, trigger frame, fire-once flag, and authority flag.

Verification#

Run:

bash
python3 V2/ue/Tools/check-v2-sequencer-event-tracks.py

Adjacent verification should include python3 V2/ue/Tools/check-v2-sequencer-audio-tracks.py, python3 V2/ue/Tools/check-v2-sequencer-animation-clip-tracks.py, python3 V2/ue/Tools/check-v2-sequencer-property-tracks.py, python3 V2/ue/Tools/check-v2-sequencer-keyframe-interpolation.py, python3 V2/ue/Tools/check-v2-sequencer-timeline-playback.py, python3 V2/ue/Tools/check-v2-sequencer-data-model.py, and python3 V2/ue/Tools/check-v2-cinematics-module.py.