SLICE: light — the sun, the coloured projection, and the look. Owns: the sun and the sky, every light in the hall, the shadows, the mechanism that throws the WINDOW'S COLOURED IMAGE into the room, the PostProcess chain, exposure, and the four act grades. HOW THE WINDOW THROWS ITS PICTURE A spot light reads `zero_feature_texture(uv, cookieLayer)` at every shaded point, with `uv` taken from that point's position in the light's own clip space. So one layer of the shared feature-texture array IS the light's image. `window_gobo.computeShader` paints that layer every frame: for each texel it takes the ray that texel stands for, walks it to the plane of the glass, and evaluates the leaded grid, the rosette, the cobalt band and the missing pane where the ray lands. Nothing is resampled, so the leads stay sharp at any throw, and the image is drawn under the obliquity the sun actually has, which is what makes the projection correctly foreshortened rather than a rubber-stamped rectangle. The projector stands 140 m out along the sun's own ray with a cone just wide enough to hold the window, so its rays are within a degree of parallel across the whole 19 m hall — sunlight, not a lamp. It casts shadows, so the counter, the teller grille, the vault door and the mezzanine cut the beam. TWO THINGS THIS SLICE HAD TO DECIDE FOR ITSELF 1. `Film.sunDirection(t)` disagrees with the convention its own comment states: it builds the horizontal from `-cos(azimuth)` where "+Z north, azimuth 180 = due south" wants `+cos(azimuth)`, so at solar noon it sends the light SOUTHWARD, out through the window instead of into the room. `demo.film` belongs to the plan and is read-only here, so this module derives the direction from `Film.sun(t).elevation/.azimuth` — the shared numbers — and publishes the corrected vector as `Light.sunDirection(t)` for any slice that wants it. 2. The bank does not sit square to the compass: its front is `WINDOW_AZIMUTH - 180` degrees east of south. Dead square, `Film.sun`'s azimuth sweep (68 deg to 292 deg) would put the first light in the room at t = 10 and take the last out at t = 89.6, and the shot list wants the first gold edge at t = 6 and the last direct sun held to t = 86. Eight and a half degrees of skew — ordinary for a plains bank platted off a section line — lands both ends where the film asks for them. The hall is a sealed brick cube, so the scene's directional sun is held at zero inside it: a second, uncoloured copy of the sun coming through the same aperture would double the light on the patch and wash the glass's colour straight out of it. Everything in the room is the projector, the skylight through the window, the bounce off the lit patch, and the sky's ambient.