02/04/2003
15-462 Graphics I
8
Types of Light Sources
•Ambient light: no identifiable source or
direction
•Point source: given only by point
•Distant light: given only by direction
•Spotlight: from source in direction
–Cut-off
angle defines a cone of light
–Attenuation
function (brighter in center)
•Light
source described by a luminance
–Each
color is described separately
–I = [Ir Ig
Ib]T (I for
intensity)
–Sometimes
calculate generically (applies to r, g, b)