twilight

# firstlight.sky.twilight The band of twilight over the southern horizon of a polar night, painted on a dome round the station. A surface shader that emits its own light and adds to the sky behind it: where the band is nothing it adds nothing, so the dome is invisible outside it. Every value is a function of the view direction, so the band stands at the same place in the sky from anywhere on the plain and the dome is only a canvas. | Property | Meaning | |---|---| | `sun_dir` | Unit vector toward the sun. The band stands over its azimuth; the glow round it arrives as it nears the horizon. | | `twilight` | 0..1, how open the noon window is. Sets the band's height, width, brightness and how far violet and rose reach into it. | | `intensity` | Overall gain. | | `blue` / `violet` / `rose` | The band's colours from its top to its foot. | Wear it with `render: { type: additive, depth_write: false, cull: none }` on a dome inside the camera's far plane; `firstlight.sky` builds that dome and drives these properties from the game clock.