make variable readonly

zhuxingwei · zhuxingwei · commit 8ef99a0a98c1 · 2019-05-14T16:21:34.000+08:00
diff --git a/Runtime/rendering/layer.cs b/Runtime/rendering/layer.cs
@@ -950,7 +950,7 @@ public FollowerLayer(
         Offset _lastOffset;
         Matrix3 _lastTransform;
 
-        Matrix3 _invertedTransform = Matrix3.I();
+        readonly Matrix3 _invertedTransform = Matrix3.I();
         bool _inverseDirty = true;
 
         internal override S find<S>(Offset regionOffset) {
