When a quantum planet is destroyed, only destroy that state (#134)

NewHorizons/Components/QuantumPlanet.cs

@@ -1,4 +1,4 @@
-using NewHorizons.Builder.General;
+using NewHorizons.Builder.General;
 using NewHorizons.Builder.Orbital;
 using NewHorizons.Components.Orbital;
 using NewHorizons.External.Modules;
@@ -21,6 +21,8 @@ namespace NewHorizons.Components
         private AlignWithTargetBody _alignment;
         private OWRigidbody _rb;
 
+        public int CurrentIndex { get { return _currentIndex; } }
+
         public override void Awake()
         {
             base.Awake();

NewHorizons/Patches/DestructionVolumePatches.cs

@@ -0,0 +1,35 @@
+using HarmonyLib;
+using NewHorizons.Components;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace NewHorizons.Patches
+{
+    [HarmonyPatch]
+    public static class DestructionVolumePatches
+    {
+        [HarmonyPrefix]
+        [HarmonyPatch(typeof(DestructionVolume), nameof(DestructionVolume.Vanish))]
+        public static bool DestructionVolume_Vanish(OWRigidbody __0)
+        {
+            var quantumPlanet = __0.gameObject.GetComponent<QuantumPlanet>();
+
+            if (quantumPlanet == null) return true;
+
+            // Allow it to vanish if this is the only state
+            if (quantumPlanet.states.Count <= 1) return true;
+
+            // Force it to change states but if it can't, remove it
+            var oldIndex = quantumPlanet.CurrentIndex;
+            quantumPlanet.ChangeQuantumState(true);
+            if (quantumPlanet.CurrentIndex == oldIndex) return true;
+
+            quantumPlanet.states.RemoveAt(oldIndex);
+
+            return false;
+        }
+    }
+}