Sky and clouds

• Sun and moon clock (SkyClock): date, time and place point the sun and moon lights, with moon phases (Meeus); the sun is within 0.0004 degrees of the ephemeris and sunrise within half a minute of the almanac (docs/bench/sky --test).
• Cloud layer (cloud_base_height, cloud_thickness, cloud_density): shaped from the weather map’s cover, cloud type and storms; drawn by WeatherSkyMaterial and seen by path traced rays (pathtracing_sky_shader_enabled).
• Clouds that never repeat (always on): shape noise read at two scales with an irrational ratio.
• Cloud reprojection (WeatherSkyMaterial.cloud_reprojection, on by default): clouds draw a sixteenth of their pixels each frame and reproject the rest (Nubis), still full resolution.
• Cloud shadows (sun_light): the clouds’ shadow is baked into the sun’s projector, matching in raster and path tracing.
• Sun projector: light_projector works on DirectionalLight3D (projector_size, projector_offset), raster and path traced.

Images#

Clouds: the layer seen from the ground, with its shadows on the field, raster and path traced.

Clouds that never repeat: seen from above over 24 km, the 3 km grid is gone.

Cloud shadows: dark patches on the ground under the clouds.