intersections: implement a PartialEq that handles floats.

rtchallenge/src/intersections.rs

@@ -7,11 +7,16 @@ use crate::{
     Float, EPSILON,
 };
 
-#[derive(Debug, Clone, PartialEq)]
+#[derive(Debug, Clone)]
 pub struct Intersection<'i> {
     pub t: Float,
     pub object: &'i Shape,
 }
+impl<'i> PartialEq for Intersection<'i> {
+    fn eq(&self, rhs: &Intersection) -> bool {
+        ((self.t - rhs.t).abs() < EPSILON) && (self.object == rhs.object)
+    }
+}
 
 impl<'i> Intersection<'i> {
     /// Create new `Intersection` at the given `t` that hits the given `object`.