Expand description
Mirror a slot’s evaluator context into its RenderState.
After the per-frame equations have run, every variable they wrote
(motion params, wave params, decay, gamma, echo, q1..q32, feedback
flags, borders, motion vectors) is read back here and packed into the
slot’s RenderState. Read-only against the evaluator; every fallback
default matches the MD2 spec so a preset that omits a variable behaves
as MilkDrop would.
Takes &mut PresetSlot so it can run against either the primary slot
(current) or the outgoing one (fading_out) during a transition.