Fleshed out Ray a bit more.

src/ray.rs

@@ -1,11 +1,15 @@
 #![allow(dead_code)]
 
+use std;
+
 use math::{Vector, Point, Matrix4x4};
 
 #[derive(Debug, Copy, Clone)]
 pub struct Ray {
     pub orig: Point,
     pub dir: Vector,
+    pub max_t: f32,
+    pub time: f32,
 }
 
 impl Ray {
@@ -13,6 +17,8 @@ impl Ray {
         Ray {
             orig: orig,
             dir: dir,
+            max_t: std::f32::INFINITY,
+            time: 0.0,
         }
     }