add: dissolve scene / nuget feed source

src/Scenes/DissolveScene.cs

@@ -0,0 +1,42 @@
+using System.Diagnostics;
+using Godot;
+using Polonium.Attributes;
+
+namespace Polonium.Scenes;
+[ProxyNode]
+public partial class DissolveScene : Scene
+{
+    [Export]
+    public Scene NextScene { get; set; }
+    private bool Finished { get; set; } = false;
+    private bool Terminated { get; set; } = false;
+
+    public override void _Process(double delta)
+    {
+        if(Finished && !Terminated)
+        {
+            Terminated = true;
+            PoloniumRegistry.Instance.RootScene.SwitchScene(NextScene);
+            return;
+        }
+
+        Process(delta);
+        base._Process(delta);
+    }
+    [ProxyMethod]
+    public virtual void Enter()
+    {
+    }
+    [ProxyMethod]
+    public virtual void Process(double delta)
+    {
+    }
+
+    public sealed override void _EnterTree()
+    {
+        Finished = false;
+        Terminated = false;
+        Enter();
+        base._EnterTree();
+    }
+}