ShipEffects: skip heavy Initialize for debris vessels#52
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JonnyOThan merged 3 commits intoMay 8, 2026
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Adds an early-exit for vesselType Debris/SpaceObject/DroppedPart in Initialize. Avoids ~150-200ms main-thread hitch on every multi-part separation in vacuum (5 new vessels x 33 sound layers each). Subscribes to GameEvents.onVesselTypeChange so debris that promotes to a real vessel (kerbal boarding a stranded vessel etc.) gets a clean reinit.
Removed the re-init handler. Promoted debris (kerbal boarding a stranded vessel) will stay silent until vessel reload - accepted as edge case. Matches existing single-part asteroid behavior, which also doesn't reinit on promotion.
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Hi,
Was profiling KSP with dotTrace and found a ~150-200ms main-thread hitch every time a part is destroyed or separated in vacuum. Tracked it down to ShipEffects.
When a Separator or any decoupler-style event fires in vacuum, KSP creates a new Vessel for each separated subassembly. On a typical multi-stage rocket that's 3-5 new Vessels in one frame. Each new Vessel instantiates ShipEffects (VesselModule, order 999), and on first OnLoadVessel runs the full Initialize - parses every SoundLayer config, calls GameDatabase.GetAudioClip for each clip, allocates new GameObject for audioParent. Around 33 sound layers per vessel times 5 vessels per separation event = ~150-200ms main thread stall.
The thing is, debris vessels don't need this. They have no engines, no command modules, no useful sound source. A drifting decoupler in space should not be running an audio engine init.
ShipEffects already has an early-exit for single-part vessels (asteroid/EVA fast path) but multi-part debris falls through.
dotTrace stack attached below.
Fix adds a debris check after the single-part exit in Initialize, plus a VesselTypeChange handler so debris that promotes to a real vessel, kerbal boarding a stranded vessel for example, gets a clean reinit. Mirrors the existing single-part asteroid/EVA fast path - sets ignoreVessel=true and returns early. Both FixedUpdate and LateUpdate already short-circuit on ignoreVessel, so debris stay silent the same way asteroids do today (the
if (ignoreVessel && controlGroup != PhysicsControl.SONICBOOM)line in the parsing loop has no runtime effect anyway since LateUpdate exits on ignoreVessel before reaching the SonicBoom code).Tested locally with a Harmony prefix doing the same thing - separation hitch is gone, normal vessels still init as before.
Thanks!