API reference

classDeathModule

Per-particle hook invoked exactly once after a particle expires, carrying its state at the moment it died. Use for sub-emitters (spawn child particles where this one died), event dispatch (trigger an audio cue, a score event), or trail termination. The callback receives a snapshot rather than a slot, and for a reason: on the GPU path the simulation runs on the device and a death is reported once its state has been read back, by which time the slot may already hold a different particle. The snapshot is therefore the same on both backends, while a slot would not be. Delivery is exactly once per expired particle, but not necessarily in the frame the particle expired: a GPU-simulated death arrives as soon as its readback lands, typically the next frame. Deaths from one readback are delivered in slot order, and readbacks in the order they were submitted. Exactly-once holds while the deaths waiting on a readback fit the system's capacity. Beyond that the excess is dropped rather than stalling the frame loop, and a development build reports it once per system. Reaching that point takes a device that falls many frames behind while slots are recycled and die again, so a system sized for its emission rate does not see it. Implementation pattern: ```ts onDeath(system, death) { this._childSystem.burstAt(death.x, death.y, 8); } ```