SETLIGHT properties

Sets how POLYVIEW illuminates polygons. The properties input is a list of two numbers ranging from 0.0 to 1.0, the amount of ambient and diffuse light. The ambient component defines how much background light there is; the larger the number the brighter the light. The diffusion component is not a property of light source, but a property of how smooth the surface is (how much it scatters light). A higher value means the objects are smoother and reflective (like marble) a low value means the objects are rough (like chalk).

To position the light use SETTURTLE -3.

SETLIGHT is designed to run in PERSPECTIVE mode. While it does run in 2D modes, the effect is not noticable without POLYVIEW.

; simple usage
SETLIGHT [0.3 0.6]
SHOW LIGHT
[0.3 0.6]

; a lightshow
TO SQUARE
  POLYSTART
  REPEAT 4 [FORWARD 100 RIGHT 90]
  POLYEND
END

PERSPECTIVE
REPEAT 72 [SQUARE RIGHTROLL 5]
POLYVIEW

REPEAT 10 [
  SETLIGHT (LIST (RANDOM 100)/100 (RANDOM 100)/100)
  SHOW LIGHT
  WAIT 60
]