renormalize world normal in pixel shader

Effects/HLSL/PBREffect.fx

@@ -162,7 +162,7 @@ float4 ComputeColor(
     float roughness
 ) {
     float3 V = normalize(EyePosition - worldPosition);
-    float3 N = worldNormal;
+    float3 N = normalize(worldNormal);
 
     float3 F0 = float3(0.04, 0.04, 0.04);
     F0 = lerp(F0, albedo, metallic);