enabled overwrite of existing pixels

Scripts/Chunk.cs

@@ -76,8 +76,8 @@ public class Chunk {
         Type type = typeof(T);
         object o = Activator.CreateInstance(type, x, y, this);
 
-        // check if not empty:
-        if (Elements[x,y].GetType() != typeof(Element)) {
+        // check if not empty and overwrite not allowed:
+        if (Elements[x,y].GetType() != typeof(Element) && !Main.Instance.AllowOverwrite) {
             return;
         }
 

Scripts/Main.cs

@@ -4,6 +4,7 @@ using Godot;
 
 public partial class Main : Node2D {
 	[Export] public bool DebugMode = false;
+	[Export] public bool AllowOverwrite = true;
 
 	[Export] public int BrushSize = 5;
 	[Export] public float TextureResolution = 0.5f;