# 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{"fill"=>"yellow","opacity"=>1} o1 = Light{Blur => .3 } cache => CacheTable{} Center => | 0 | | 0 | | 0 | | 1 | Radius => 10 Specular => 64 Static => true style => MutableHashTable{...3...} 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(0..3,i->Polygon{f#i,"fill"=>c#i,"stroke"=>"none"}), Light{[110,0,0],Radius=>10,"opacity"=>"1"},ViewPort=>{vector{-110,-100},vector{110,100}}, Size=>40,TransformMatrix=>rotation(-1.5,[4,1,0])) o5 = tetra o5 : GraphicsList

## Caveat

Do not use the same Light object multiple times within the same GraphicsObject.

## For the programmer

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