Michal Iwanicki

*received* power per unit area from uniform dome light source Int(Li * cos(theta))=Li*pi

but specifying *emitted* power/area non-intuitive for domes - not what light meters measure

light meters use lumisphere vs lumidisc for this purpose

i.e. give same illuminance regardless of the source direction

so no cos weighting, which maked sense since why would you weight rel. arbitrary plane normal

because that's what "illuminance" is - it's flux per area arriving at a surface - so with cos

cos assumes that area is plane facing up, which is not the case with lumisphere

For use in gfx u want a measure at sth resembling differential area: lumidisc/retracted sphere