# film The shared constants and the film clock for DEADLIGHT. Every slice of the demo reads this module and nothing restates its numbers. It holds three things: - The timing spine — the 14 shots, their durations and their windows. `Film.SHOTS`, `Film.shotAt(t)`, `Film.window(n)`, `Film.movementAt(t)`. Durations live here and nowhere else. - The world contract — the shared coordinate frame (`Film.WORLD`), the named entities each slice owns (`Film.NAMES`), the submersible's contracted path (`Film.SUB_PATH` / `Film.subPoseAt(t)`), the anchor fallbacks that let the film play while it is still being built (`Film.ANCHORS`), the palette (`Film.PALETTE`) and the water's optics (`Film.WATER`). - The clock — a fixed 1/24 s step advanced once per RENDERED frame by `deadlight.FilmDirector`, never from wall time. 2,256 rendered frames is exactly the 94-second film, every time. ```luau local Film = require("deadlight.film") Film.restart() -- t := 0, every slice resets, playing := true Film.seek(48.0) -- deterministic scrub to a moment Film.status() -- where the film is and who has joined it Film.register("abyss", { -- join from your own component's awake() reset = function() end, tick = function(t, dt) end, shot = function(n, tLocal) end, }) ``` Handlers run inside `pcall`, so one slice erroring cannot stop the film for the others. Registering a name twice replaces its handlers.

# water_extinction The medium DEADLIGHT swims in, as one full-screen pass. Every pixel is re-lit for the water standing between it and the lens: what the surface sent toward the camera is attenuated by per-channel Beer-Lambert extinction over the real distance, and what the water itself scatters into the eye path is added over it. Red dies at 0.19 per metre against 0.032 for blue, which is why rust reads brown at two metres and blue-grey at twelve, and why nothing past the lamps' reach is visible at all. The black at the edge of frame is absence, not fog — with no light in the water there is nothing to scatter in, which is what `inscatter` falling to `void_color` says. Distance is unprojected from the depth buffer through the frame's own inverse view-projection, so every camera measures its own water rather than inheriting the main camera's near and far planes. A pixel with no surface behind it is measured to the far plane, so an empty direction — straight up included — fills with the same water and the frame never shows a sky. `inscatter`, `void_color`, `surface_y` and `column_falloff` are written once per film frame from `Film.depthAt(t)`: one number carries the descent from cobalt through prussian to void.