b3d-elevator

A platform that goes up and down, and carries you with it. Three ways to ask it to move — it just runs, you stand on it, or you throw a switch — which are the three an arena needs and the three that behave differently when something goes wrong.

Riding is free, and that is worth knowing

There is no code here that carries a passenger. b3d-biped already snaps its feet to whatever is under them each frame, within STEP_UP (0.5m) and STEP_DOWN (0.6m) — so a platform moving at a plausible speed moves perhaps 0.02m between frames and the character simply stays on it, going up or down.

That is the whole reason this element is small. A lift that grabs its riders has to decide what a rider IS, what happens when one jumps, and how to hand them back — and every one of those decisions is a bug waiting for an edge case. Not answering the question at all turned out to be available.

⚠️ It stops being free if the platform outruns the snap: faster than about STEP_DOWN per frame (roughly 36 m/s at 60fps) a descending platform drops out from under you and you fall after it. That is a fine speed for a trap and a bad one for a lift.

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