Renders each emitter instance's particles as a single continuous, camera-facing
strip — the particles are the spine, in spawn order (spec 01, Stage 4). One
strip per emitterInstanceId, so every child-emitter trail is its own ribbon.
Rebuilt each onSystemUpdate from the live particles the renderer is tracking;
width tapers with particle scale, colour/alpha come from the particle. Handles
the degenerate cases: a group of fewer than two points is hidden, and
zero-length segments reuse the previous orientation rather than emit NaNs.
Renders each emitter instance's particles as a single continuous, camera-facing strip — the particles are the spine, in spawn order (spec 01, Stage 4). One strip per
emitterInstanceId, so every child-emitter trail is its own ribbon.Rebuilt each
onSystemUpdatefrom the live particles the renderer is tracking; width tapers with particle scale, colour/alpha come from the particle. Handles the degenerate cases: a group of fewer than two points is hidden, and zero-length segments reuse the previous orientation rather than emit NaNs.