1 files changed, 2 insertions, 2 deletions
diff --git a/src/sphere.rs b/src/sphere.rs
index 9ea9081..f1c88b6 100644
--- a/src/sphere.rs
+++ b/src/sphere.rs
@@ -8,11 +8,11 @@ use crate::ray::Ray;
 pub struct Sphere {
     center: Vector3<f64>,
     radius: f64,
-    material: Box<dyn Material>
+    material: Box<dyn Material + std::marker::Sync>
 }
 
 impl Sphere {
-    pub fn new(center: Vector3<f64>, radius: f64, material: Box<dyn Material>) -> Sphere {
+    pub fn new(center: Vector3<f64>, radius: f64, material: Box<dyn Material + std::marker::Sync>) -> Sphere {
         Sphere { center, radius, material }
     }
 }