CSE 615, Fall 2002

Homework 3: Occlusion based Culling

1. Build a scene with densly packed spheres.

The spheres are composed of k polygons and there are n spheres.  Spheres may have
different radii.

Fix your viewpoint somewhere in front of the group of spheres as shown above.

(a) From the viewpoint, implement a simple algorithm to choose a good occluder set.

(b) Use the occlusion map and depth estimation buffer technique to cull away the occluded spheres
(make a decision not to draw certain spheres at object level).  Note that computing the closest
point of the sphere to the viewpoint, the projected size of the sphere on the image plane (which
would be a circle), and overlap test is simpler compared to the general case.

(c) Due to the overhead, the culling approach may not work with interactive frame rate.  
Vary the number of spheres (n) and polygons per spheres (k) to see the effect of the trade off.