deadlight.abyss.motes

Everything suspended in the water, as six GPU emitters stepped by exactly Film.DT once per rendered frame from the film's own clock.

• snow — marine snow, a box the camera lives inside. World-static and sinking at four centimetres a second, so what makes it stream is the camera's own travel through it. It is the only readout that the submersible is falling.
• wake — snow the vehicle drags with it, thrown along its travel, killed by drag in about a second, then drifting back up. That is what "the snow inverts direction as it passes" is made of.
• silt — the slow roll ahead of the downwash, the curtain hanging in the beams over the deck, the curl out of an open porthole.
• bloom — the same sediment thrown hard instead of lifted: the thruster jet that blanks the frame, and the cloud the take-off kicks up.
• amphipods — the scavengers that boil out of the sediment the moment a light hits it.
• flakes — corrosion the thrusters shake off the plating. It falls rather than billows.

Each disturbance names the window it runs in and where it comes from, and rises, holds and falls across it — a disturbance rather than a switch. Every one is a function of Film.t and of nothing else.

tick(t, dt, stepped) takes stepped = false while the clock is being scrubbed through many film frames inside one rendered frame, and leaves the emitters alone; the driver catches them up afterwards over a bounded run.

A mote is visible at its own colour whether a lamp reaches it or not. The sprite program adds a point-light pickup on top of the particle's colour and lightInfluence reaches no shader (#10085), so what keeps the void empty is the colour itself: dark enough to disappear into the water, brought up several times over by a flood that actually reaches it.