Feedback trails — trails

Routes the composited frame through a fade-and-accumulate feedback (max-decay), so moving shapes leave light trails. trails = 0 (default) is off; 0 < trails < 1 sets the decay (higher = longer trails). Best on a scene with real motion (a spinning curve, a drifting swarm).

trails is retention per 1/60 s, not per frame. The stage raises it to the dt-relative power, so a trails = 0.9 tail lasts the same wall-clock time on a 48 Hz laptop and a 144 Hz monitor — applied once per frame instead, the same preset’s trails would be a third as long at 144 Hz. Captures are unaffected: the harness steps a fixed 1/60 s, where the exponent is exactly 1.