ambientShadow

Multiplier for shadowed-fragment colour on UNLIT receivers (terrain imagery, photogrammetry, points), where the shadow term is the only sun shading. 0.0 => fully black shadow, 1.0 => no darkening; the default 0.4 is a perceptual mid-point that reads as a directional shadow without obscuring the underlying albedo. Lit receivers ignore it - their shadow floor is the scene ambient term (see earth.worldwind.render.program.LightingGlsl).