nearside_sky

The sky over the Moon's nearside at the hour of sunrise: airless black, hard stars, a half-lit Earth hanging in the north, and a grazing warm glare hugging whichever horizon the sun is under.

There is no air here, so nothing in this shader scatters. The two lifts along the horizon are the regolith out to the skyline catching light and throwing it back up — cinnamon on the sun's side, earthlight opposite — and above a few degrees the sky is space.

Earth is drawn as a disc along a fixed world direction rather than as geometry: it is a real sphere shaded from its own light vector, with procedural continents, ice, cloud, an ocean glint, city light on the night side and an atmosphere rim that brightens on the lit limb. Being a sky pixel it sits at infinity, never clips, and costs no draw call.

Its earth_dir and earth_radius are driven from the live screen size by game.dawn.Dawn, which puts Earth higher and larger on a tall frame than on a wide one, so it lands in the top band of either.

sun_direction arrives as the direction the light TRAVELS, so the sun stands at the negative of it.