✨ Placement check with collision

Scripts/System/PlacementManager.cs

@@ -24,13 +24,29 @@ public partial class PlacementManager : Node2D
             AddChild(_ghostBuilding);
         }
 
-        _ghostBuilding.Position = GridUtils.GridToWorld(_hoveredCell);
-        _ghostBuilding.SetGhostMode(true);
+        var placementPos = GridUtils.GridToWorld(_hoveredCell);
+        var spaceState = GetWorld2D().DirectSpaceState;
+        var centerPos = placementPos + new Vector2(GridUtils.TileSize / 2f, GridUtils.TileSize / 2f);
+
+        var query = new PhysicsPointQueryParameters2D
+        {
+            Position = centerPos,
+            CollideWithBodies = true,
+            CollideWithAreas = true,
+            CollisionMask = uint.MaxValue // check against all layers/masks
+            // Exclude = new Godot.Collections.Array<Rid>() // optional, see below
+        };
+
+        var collision = spaceState.IntersectPoint(query, 8);
+        var canPlace = Grid.IsCellFree(_hoveredCell) && collision.Count == 0;
+
+        _ghostBuilding.Position = placementPos;
+        _ghostBuilding.SetGhostMode(canPlace);
 
         // Left click to place
-        if (!Input.IsActionPressed("build_tile") || !Grid.IsCellFree(_hoveredCell)) return;
+        if (!Input.IsActionPressed("build_tile") || !canPlace) return;
 
-        _ghostBuilding.SetGhostMode(false);
+        _ghostBuilding.FinalizePlacement();
         Grid.OccupyCell(_hoveredCell, _ghostBuilding);
 
         _ghostBuilding = (BaseTile)BuildingScene.Instantiate();

Scripts/Tiles/BaseTile.cs

@@ -1,30 +1,45 @@
 using Godot;
 
-namespace AceFieldNewHorizon.Scripts.Tiles;
-
-public partial class BaseTile : Node2D
+namespace AceFieldNewHorizon.Scripts.Tiles
 {
-    protected CollisionShape2D CollisionShape;
-    protected Sprite2D Sprite;
-
-    public override void _Ready()
+    public partial class BaseTile : Node2D
     {
-        // Get references (optional: you can also Export and assign in editor)
-        CollisionShape = GetNode<CollisionShape2D>("CollisionShape2D");
-        Sprite = GetNode<Sprite2D>("Sprite2D");
-    }
+        private CollisionShape2D _collisionShape;
+        private Sprite2D _sprite;
 
-    public void SetGhostMode(bool ghost)
-    {
-        if (CollisionShape != null)
-            CollisionShape.Disabled = ghost;
-
-        if (Sprite != null)
+        public override void _Ready()
         {
-            if (ghost)
-                Sprite.Modulate = new Color(1, 1, 1, 0.5f); // semi-transparent
-            else
-                Sprite.Modulate = Colors.White;
+            _collisionShape = GetNodeOrNull<CollisionShape2D>("CollisionShape2D");
+            _sprite = GetNodeOrNull<Sprite2D>("Sprite2D");
+        }
+
+        /// <summary>
+        /// Switch between ghost and placed mode.
+        /// </summary>
+        /// <param name="canPlace">If in ghost mode, true = green, false = red. If placed, always white.</param>
+        public void SetGhostMode(bool canPlace)
+        {
+            if (_collisionShape != null)
+                _collisionShape.Disabled = true; // always disabled in ghost mode
+
+            if (_sprite != null)
+            {
+                // Ghost preview coloring
+                _sprite.Modulate = canPlace ? new Color(1, 1, 1, 0.2f) : // white semi-transparent
+                    new Color(1, 0, 0, 0.2f); // red semi-transparent
+            }
+        }
+
+        /// <summary>
+        /// Call when placement is finalized.
+        /// </summary>
+        public void FinalizePlacement()
+        {
+            if (_collisionShape != null)
+                _collisionShape.Disabled = false;
+
+            if (_sprite != null)
+                _sprite.Modulate = Colors.White; // reset to normal
         }
     }
 }