Improve city interaction when there's only 1 nhood

Documentation/Crafting a City.md

@@ -111,6 +111,8 @@ There are a few things you can do in the neighbourhood editor:
   - Move a neighbourhood's origin point to the mouse position. The neighbourhood visualization will update to show you what area of the city belongs to which neighbourhood.
 - Hold shift & Click
   - Create a new neighbourhood at the mouse position.
+- Hold ctrl & Click
+  - Delete the neighbourhood at the mouse position. Needs to be pretty close.
 - Press "R"
   - Rename the neighbourhood closest to the mouse position.
 - Press "C"
@@ -120,7 +122,7 @@ There are a few things you can do in the neighbourhood editor:
 - Press Shift + F10
   - Save the neighbourhood data to `Content/edit_neigh.json`.
 
-Similar to the City Painter, this tool is currently pretty user unfriendly, so improvements would definitely be welcome. For example, not being able to delete neighbourhoods is a bit silly, but you can always save to JSON, manually delete it with a text editor, then load it again.
+Similar to the City Painter, this tool is currently pretty user unfriendly, so improvements would definitely be welcome.
 
 Descriptions for neighbourhoods also can't be edited ingame. Add a `description` field to each object in the JSON to give your neighbourhoods a description that appears in their nhood page. You can also do this in the database after importing.
 

TSOClient/tso.client/Rendering/City/CityCamera3D.cs

@@ -22,6 +22,45 @@ namespace FSO.Client.Rendering.City
         private UILotControlTouchHelper Touch;
         public CityCameraCenter CenterCam { get; set; }
 
+        // Set a center delta, then tween to 0 to smootly move to a target location.
+
+        public Vector2 CenterDelta;
+        public float TweenDeltaX
+        {
+            get
+            {
+                return CenterDelta.X;
+            }
+
+            set
+            {
+                if (CenterDelta.X != 0)
+                {
+                    CenterTile.X -= value - CenterDelta.X;
+                }
+
+                CenterDelta.X = value;
+            }
+        }
+
+        public float TweenDeltaY
+        {
+            get
+            {
+                return CenterDelta.Y;
+            }
+
+            set
+            {
+                if (CenterDelta.Y != 0)
+                {
+                    CenterTile.Y -= value - CenterDelta.Y;
+                }
+
+                CenterDelta.Y = value;
+            }
+        }
+
         public float FarUIFade
         {
             get { return Math.Max(0, Math.Min(1, 6.5f - Zoom3D)); }

TSOClient/tso.client/Rendering/City/CityNeighGeom.cs

@@ -80,6 +80,8 @@ namespace FSO.Client.Rendering.City
             int halfMapSize = mapSize / 2;
             int margin = 512;
 
+            // These points stop the neighbourhood geometry from going too far out of bounds, which would cause visual issues.
+
             pts.Add(new Vector2(halfMapSize, -margin));
             pts.Add(new Vector2(-margin, halfMapSize));
 
@@ -476,7 +478,8 @@ namespace FSO.Client.Rendering.City
                 //find the nhood we're hovering
                 var pos = City.EstTileAtPosWithScroll(state.MouseState.Position.ToVector2() / FSOEnvironment.DPIScaleFactor, null);
                 
-                if (City.HandleMouse)
+                // Neighbourhoods are only interactive if there's more than one.
+                if (City.HandleMouse && City.NeighGeom.Cells.Count > 1)
                 {
                     HoverNHood = NhoodNearest(pos);
                     if (HoverNHood > -1 && !HoverPct.ContainsKey(HoverNHood))

TSOClient/tso.client/Rendering/City/Terrain.cs

@@ -1102,9 +1102,18 @@ namespace FSO.Client.Rendering.City
 
                         //((CityCamera2D)Camera).m_TargVOffX = (float)(-hb + pt.X * isoScale * 2);
                         //((CityCamera2D)Camera).m_TargVOffY = (float)(vb - pt.Y * isoScale * 2); //zoom into approximate location of mouse cursor if not zoomed already
-                    } else
+                    }
+                    else
                     {
-                        if (currentTile != null) ((CityCamera3D)Camera).CenterTile = currentTile.Value;
+                        var camera = (CityCamera3D)Camera;
+                        if (currentTile != null)
+                        {
+                            camera.CenterDelta = currentTile.Value - camera.CenterTile;
+                            GameFacade.Screens.Tween.To(camera, 0.3f, new Dictionary<string, float>() {
+                                { "TweenDeltaX", 0f },
+                                { "TweenDeltaY", 0f },
+                            }, TweenQuad.EaseOut);
+                        }
                         ((CityCamera3D)Camera).TargetZoom = 1.7f;
                     }
                 }