Fighting Game · Guides & deep dives

V2 Cross-Fade Transition Effects

CrossFadeTransitionEffects_V2_Contract.json

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Source Of Truth#

  • Task: TODOS.phase-72.72.22.1.8
  • Contract: CrossFadeTransitionEffects_V2_Contract.json
  • Core types: EV2CrossFadeCurve, FV2CrossFadeTransitionEffectRule, FV2CrossFadeTransitionEffectRequest, FV2ResolvedCrossFadeTransitionEffect, and FV2CrossFadeTransitionEffectCatalog
  • Builder: UV2AudioBlueprintLibrary::BuildDefaultCrossFadeTransitionEffectCatalog
  • Validator: UV2AudioBlueprintLibrary::ValidateCrossFadeTransitionEffectCatalog
  • Resolver: UV2AudioBlueprintLibrary::ResolveCrossFadeTransitionEffect
  • Registrar: UV2AudioSubsystem::RegisterCrossFadeTransitionEffectCatalog
  • Scheduler: UV2AudioSubsystem::ScheduleCrossFadeTransitionEffect

Curve And Duration Coverage#

The default CrossFadeTransitionEffects.V2 catalog is authored with all launch fade curve classes and transition ids:

  • Linear
  • EqualPower
  • EaseInOut
  • Music.TransitionEffect.ExplorationVerseToChorus
  • Music.TransitionEffect.TensionVerseToChorus
  • Music.TransitionEffect.CombatMainToDefeatKO
  • Music.Section.Exploration.Verse->Music.Section.Exploration.Chorus
  • Music.Section.Tension.Verse->Music.Section.Tension.Chorus
  • Music.State.Combat.Main->Music.State.Defeat.KO

Each FV2CrossFadeTransitionEffectRule carries configurable FadeOutSeconds, FadeInSeconds, OverlapSeconds, EV2CrossFadeCurve, and an AudioMod.CrossFadeTransition.* modulation control. Rules must expose configurable fade durations and curves, use positive overlap inside both fade windows, and remain rollback-cosmetic.

Runtime Behavior#

FV2CrossFadeTransitionEffectCatalog::ResolveTransitionEffect looks up the authored source and target segment pair, applies optional request-level fade and overlap overrides, clamps overlap to the active fade windows, and returns the incoming start and outgoing end times. Accepted results set bUsesSmoothOverlap, carry the selected curve, and report a stable Audio.CrossFadeTransition.Accepted.* reason tag.

UV2AudioConfigAsset owns the default transition-effect catalog. UV2AudioSubsystem::RegisterAudioConfig registers it before beat-synchronized transition rules so a higher-level music conductor can pair beat timing with smooth fade envelopes. Runtime snapshots expose the rule count, configurable duration and curve flags, smooth-overlap coverage, and the last scheduled transition effect id, target segment, and overlap duration.

Validation Commands#

bash
python3 V2/ue/Tools/check-v2-cross-fade-transition-effects.py
python3 V2/ue/Tools/check-v2-beat-synchronized-transitions.py
python3 V2/ue/Tools/check-v2-audio-module.py
python3 V2/tools/validate-v2-docs.py
python3 -m json.tool V2/ue/Content/V2/Audio/CrossFadeTransitionEffects_V2_Contract.json