LightSources is an option for Graphics3D and related functions that specifies the properties of point light sources for simulated illumination.
The basic form is LightSources
, ... , where the are the specifications for each light source. Each has the form
. The direction is specified as
, where the components are with respect to the final display area. The and are horizontal and vertical in the plane of the display; is orthogonal to the display. Positive is in front. Only the relative magnitude of the components is relevant; the overall normalization of the vector is ignored. The color can be specified by GrayLevel, Hue or RGBColor.
Simulated illumination determines the shading of polygons in three-dimensional pictures.
The shading of a particular polygon is computed as a sum of contributions from point light sources, plus a contribution from ambient light.
Surface properties of polygons are specified by SurfaceColor directives.
Light reflection properties assumed for polygons are described in the notes for SurfaceColor.