Classical Ray Tracing

1
Classical Ray Tracing

• Object/Ray intersection after Haines course notes.

2
Representation of Ray

• Parametric
• where R0 is origin of ray
• t is distance along ray

3
Sphere

• Implicit eqn. for sphere.
• Sc is center, Sr is radius.
• Surface points on sphere are Xs Ys Zs
• where

4
Ray/Sphere Intersection

• Substitute equation for ray into that for sphere
  to get
• and solve for t to figure out where hit along the
  ray.
• Assuming ray direction Rd is normalized, we get
  (derivation in Haines)

5
Solution for t

• where

(compute world-space location from value of t)