Index: shaders/ship.frag
===================================================================
--- shaders/ship.frag	(revision 5a1ace07fab99988e1cc16659663dd54921b15f4)
+++ shaders/ship.frag	(revision a52ba8741a9a401499b6ca8a1b53d3da6a461384)
@@ -57,4 +57,4 @@
    vec3 Is2 = Ls * Ks * specular_factor2;
 
-   frag_color = vec4((Is + Id + Ia + Is2 + Id2 + Ia2)/2, 1.0);
+   frag_color = vec4((Is + Id + Ia + Is2 + Id2 + Ia2) / 2.0, 1.0);
 }