diff --git a/src/graphics/shader.wgsl b/src/graphics/shader.wgsl
index 89588cf98..cdd201ad4 100644
--- a/src/graphics/shader.wgsl
+++ b/src/graphics/shader.wgsl
@@ -35,7 +35,7 @@ let pi: f32 = 3.14159265359;
 fn frag_model(in: VertexOutput) -> [[location(0)]] vec4<f32> {
     let light = vec3<f32>(0.0, 0.0, -1.0);
 
-    let angle = acos(dot(light, -in.normal));
+    let angle = acos(abs(dot(light, -in.normal)));
     let f_angle = angle / (pi / 2.0);
 
     let f_normal = max(1.0 - f_angle, 0.0);