lightDirection

World-space (Cartesian) unit vector pointing toward the light source. Resolved by earth.worldwind.WorldWind each frame before any layer renders: the sun position when WorldWind.time is set, a custom WorldWind.lightDirectionProvider direction, or the surface normal at the camera's geographic position (a "light from above the user's foot point") as the default. Shape lighting, shadows and atmospheric scattering all read the same vector.