Ray Tracing

Goddamn all of these homework threads. Let's talk about something interesting.

I'm starting work on a ray-tracer for shits, /proggles/ Any tips on speed improvements? It's being written in C.
I know the show stopper (usually) is having to check each element in the scene and see if it has been intersected by a casted ray. Any ideas on improvements in that area?

>>48
"Ray tracer" that use printf as display device and output lines?
also the sphere coords are hardcoded into tracer:
 "1111886:6:??AAFFHHMMOO55557799@@>>>BBBGGIIKK"[b]-64;
 "C@=::C@@==@=:C@=:C@=:C531/513/5131/31/531/53"[b]-64;