pointer-field-craft

pointer-field-craft

Build the emitter when trail density must follow hand speed.

Emit by distance, not time (the core mechanism)

E.acc += moved;
let guard = 0;
while (E.acc >= STEP && guard++ < 14) {
  E.acc -= STEP;
  spawn(/* … */);
}

Timer emission makes spacing ∝ speed — flicks scatter; resting hands pile motes. Cap the loop so teleports / tab restores cannot spawn thousands in one frame.

Place each mote where it is owed

Lay along the segment (t = guard * STEP / moved), not all at the current tip.

Ring-buffer: take the slot before advancing

const i = E.i; E.i = (i + 1) % N; // correct — advance after write

Advancing first makes every mote appear one step behind.

Lag the emitter behind the pointer

Damp toward the pointer so flicks keep slack instead of welding the trail to the cursor.

Also learn

• Idle breath when distance emission would go silent
• Coast instead of hard stop
• Touch + prefers-reduced-motion → disable or static
• Pause when document.hidden or section not intersecting
• Prefer canvas overlay; moving emitter solely to raise z-index rarely pays off

Tell constraints

• Default product UI: off (distracts from proof stages)
• Allowed as opt-in on art-directed studio heroes with reduced-motion off and content contrast intact
• Never attach listeners per mote; one pointer listener on the field root