fixed rotate and translate unit test

Author: Jannik-Hm

tests/MeshTypes/mesh_test.go

@@ -85,6 +85,18 @@ func TestRotateAndTranslate(t *testing.T) {
 		triangle.V0.Position = translationMatrix.MulPosition(triangle.V0.Position) // safe to use as func is tested in another place
 		triangle.V1.Position = translationMatrix.MulPosition(triangle.V1.Position)
 		triangle.V2.Position = translationMatrix.MulPosition(triangle.V2.Position)
+		if triangle.V0.Normal != nil {
+			n0 := translationMatrix.MulDirection(*triangle.V0.Normal)
+			triangle.V0.Normal = &n0
+		}
+		if triangle.V1.Normal != nil {
+			n1 := translationMatrix.MulDirection(*triangle.V1.Normal)
+			triangle.V1.Normal = &n1
+		}
+		if triangle.V2.Normal != nil {
+			n2 := translationMatrix.MulDirection(*triangle.V2.Normal)
+			triangle.V2.Normal = &n2
+		}
 	}
 	if !reflect.DeepEqual(result, want) {
 		t.Errorf("Mesh RotateAndTranslate() Output does not match expected")