Illumination 2

More on lighting!

what 3 things are a light source modelled by

its location in the world, the direction of emission and energy intensity at each wavelength

distributed light source

large surface, radiate from the entire surface

ambient light

provide the same amount of light to every point in the room

point source

a sufficiently distant light source which radiates light equally in all directions

issue with point source

they create very sharp, unnatural shadows

how can we solve point source issue?

distributed sources create softer transitions. or ambient light can also soften the shadows

spotlight

characterised by a narrow range of angles, can be approximated by a point source and a cone that limits the allowed angle of light

distant light sources

when light is very distant, the angle of incidence is parallel anywhere on an illuminated surface

phong reflection vector 1

n - normal at point P

phong reflection vector 2

v - points at the viewer (COP)

phong reflection vector 3

l - points at light source

phong reflection vector 4

r - direction of perfect reflection of l

what two matrices does the phong reflection model use

illumination representing light and reflection representing the material