//?[header]
//?A?very?basic?raytracer?example.
//?[/header]

//?This?program?is?free?software:?you?can?redistribute?it?and/or?modify
//?it?under?the?terms?of?the?GNU?General?Public?License?as?published?by
//?the?Free?Software?Foundation?either?version?3?of?the?License?or
//?（at?your?option）?any?later?version.
//
//?This?program?is?distributed?in?the?hope?that?it?will?be?useful
//?but?WITHOUT?ANY?WARRANTY;?without?even?the?implied?warranty?of
//?MERCHANTABILITY?or?FITNESS?FOR?A?PARTICULAR?PURPOSE.??See?the
//?GNU?General?Public?License?for?more?details.
//
//?You?should?have?received?a?copy?of?the?GNU?General?Public?License
//?along?with?this?program.??If?not?see?.


#include?
#include?
#include?
#include?