将Spline移出Plugin，以调整SplineRenderer的OnWillCameraRender

Assets/Dreamteck/Utilities/PrivateSingleton.cs

@@ -0,0 +1,52 @@
+namespace Dreamteck
+{
+    using System.Linq;
+    using UnityEngine;
+
+    public class PrivateSingleton<T> : MonoBehaviour where T : Component
+    {
+        [SerializeField] protected bool _dontDestryOnLoad = true;
+        [SerializeField] protected bool _overrideInstance = false;
+
+        protected static T _instance;
+
+        protected virtual void Awake()
+        {
+            if (_instance != null && _instance != this)
+            {
+                if (_overrideInstance)
+                {
+                    Destroy(_instance.gameObject);
+                    _instance = this as T;
+                    Init();
+                }
+                else
+                {
+                    Destroy(this.gameObject);
+                }
+            }
+            else
+            {
+                _instance = this as T;
+
+                if (_dontDestryOnLoad)
+                {
+                    DontDestroyOnLoad(gameObject);
+                }
+                Init();
+            }
+        }
+
+        protected virtual void Init()
+        {
+        }
+
+        protected virtual void OnDestroy()
+        {
+            if (_instance == this && !_overrideInstance)
+            {
+                _instance = null;
+            }
+        }
+    }
+}