Fixed bug and add test

src/math/bounding_box.rs

@@ -71,10 +71,10 @@ macro_rules! make_bounding_box {
             pub fn intersection(&self, other: &$name<T>) -> $name<T> {
                 let mut ret = self.clone();
                 for i in 0..$size {
-                    if ret.min()[i] > other.min()[i] {
+                    if ret.min()[i] < other.min()[i] {
                         ret.min_mut()[i] = other.min()[i];
                     }
-                    if ret.max()[i] < other.max()[i] {
+                    if ret.max()[i] > other.max()[i] {
                         ret.max_mut()[i] = other.max()[i];
                     }
                 }
@@ -101,6 +101,9 @@ mod tests {
     use math::vector::Vector2;
     use math::bounding_box::BoundingBox2;
 
+    use math::vector::Vector3;
+    use math::bounding_box::BoundingBox3;
+
     #[test]
     fn initialization() {
         use std::f64::{MIN, MAX};
@@ -121,4 +124,26 @@ mod tests {
         assert_delta!(bounding_box.max().x(), v1.x(), 0.01);
         assert_delta!(bounding_box.max().y(), v2.y(), 0.01);
     }
+
+    #[test]
+    fn intersection() {
+        let b1 = BoundingBox3::new(
+            Vector3::new(0, 0, 0),
+            Vector3::new(2, 2, 2),
+        );
+
+        let b2 = BoundingBox3::new(
+            Vector3::new(1, 1, 1),
+            Vector3::new(3, 3, 3),
+        );
+
+        let b = b1.intersection(&b2);
+        assert_eq!(b.min().x(), 1);
+        assert_eq!(b.min().y(), 1);
+        assert_eq!(b.min().z(), 1);
+
+        assert_eq!(b.max().x(), 2);
+        assert_eq!(b.max().y(), 2);
+        assert_eq!(b.max().z(), 2);
+    }
 }