fx: always true comparison

src/camera.rs

@@ -224,7 +224,7 @@ impl Camera {
     }
 
     fn ray_colour(&self, hittables: &Vec<Arc<dyn Hittable>>, r: &Ray, depth: u32) -> Colour {
-        if depth <= 0 {
+        if depth == 0 {
             return Colour::default();
         }