# Light -- A source of light

## Description

A source of light for a 3d SVG picture. This corresponds to the SVG "specular" lighting, use the property Specular. The location is given by Center. By default a Light is invisible (it has opacity 0) and is unaffected by matrix transformations outside it (Static true).

 i1 : Light{Radius=>10,"opacity"=>"1","fill"=>"yellow"} o1 = Light{Blur => .3 } cache => CacheTable{} Center => | 0 | | 0 | | 0 | | 1 | fill => yellow Is3d => true opacity => 1 Radius => 10 Specular => 64 Static => true stroke => none o1 : Light i2 : v={(74.5571, 52.0137, -41.6631),(27.2634, -29.9211, 91.4409),(-81.3041, 57.8325, 6.71156),(-20.5165, -79.9251, -56.4894)}; i3 : f={{v#2,v#1,v#0},{v#0,v#1,v#3},{v#0,v#3,v#2},{v#1,v#2,v#3}}; i4 : c={"red","green","blue","yellow"}; i5 : tetra=gList(apply(4,i->Polygon{f#i,"fill"=>c#i,"stroke"=>"none"}), Light{(110,0,0),Radius=>10,"opacity"=>"1"},ViewPort=>{(-110,-100),(110,100)}, SizeY=>30,TransformMatrix=>rotation(-1.5,(4,1,0))) o5 = tetra o5 : GraphicsList

## Caveat

Do not use the same Light object multiple times in a given GraphicsList.

## For the programmer

The object Light is an instance of the type GraphicsType, with ancestor classes Circle < GraphicsObject < HashTable < Thing.