updated to godot 4.5

fixed fall speed
improved naming

FOU.csproj

@@ -1,6 +1,9 @@
-<Project Sdk="Godot.NET.Sdk/4.2.2">
+<Project Sdk="Godot.NET.Sdk/4.5.1">
   <PropertyGroup>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net8.0</TargetFramework>
     <EnableDynamicLoading>true</EnableDynamicLoading>
   </PropertyGroup>
+  <ItemGroup>
+    <Content Include="benchmark.txt" />
+  </ItemGroup>
 </Project>

FOU.csproj.old.1

@@ -0,0 +1,12 @@
+<Project Sdk="Godot.NET.Sdk/4.4.1">
+  <PropertyGroup>
+    <TargetFramework>net8.0</TargetFramework>
+    <EnableDynamicLoading>true</EnableDynamicLoading>
+  </PropertyGroup>
+  <ItemGroup>
+    <Content Include="benchmark.txt" />
+  </ItemGroup>
+  <ItemGroup>
+    <Folder Include="UI\" />
+  </ItemGroup>
+</Project>

Scenes/FPSLabel.cs

@@ -2,7 +2,8 @@ using Godot;
 
 public partial class FPSLabel : Label
 {
-	bool ShowFPS = true;
+	[Export]
+	public bool ShowFPS = true;
 
 	// Called every frame. 'delta' is the elapsed time since the previous frame.
 	public override void _Process(double delta) {

Scenes/FPSLabel.cs.uid

@@ -0,0 +1 @@
+uid://d3cbk8f7lckbr

Scenes/PerfDetails.cs

@@ -0,0 +1,17 @@
+using FOU.Scripts;
+using Godot;
+
+public partial class PerfDetails : Label
+{
+	public override void _Process(double delta)
+	{
+		Text = "";
+		if (!Main.Instance.DebugMode) return;
+
+		int activeElements = 0;
+		foreach (Chunk c in Main.Instance.Level.GetChunks())
+			activeElements += c.ActiveElementsCount();
+
+		Text += $"Active Elements: {activeElements}";
+	}
+}

Scenes/PerfDetails.cs.uid

@@ -0,0 +1 @@
+uid://52grhydeyy0t

Scenes/SettingsController.cs

@@ -1,4 +1,3 @@
-using System.Reflection;
 using Godot;
 
 public partial class SettingsController : VBoxContainer
@@ -18,7 +17,7 @@ public partial class SettingsController : VBoxContainer
 		slSize.Value = main.BrushSize;
 
 		slRain.ValueChanged += OnRainValueChanged;
-		slRain.Value = main.RainAmount;
+		slRain.Value = main.rainAmount;
 	}
 
 	private void OnSizeValueChanged(double value) {

Scenes/SettingsController.cs.uid

@@ -0,0 +1 @@
+uid://dxmkbb5f1t368

Scenes/main.tscn

@@ -1,14 +1,14 @@
-[gd_scene load_steps=4 format=3 uid="uid://cf34vk5r055dx"]
+[gd_scene load_steps=5 format=3 uid="uid://cf34vk5r055dx"]
 
-[ext_resource type="Script" path="res://Scripts/Main.cs" id="1_k1i8e"]
-[ext_resource type="Script" path="res://Scenes/FPSLabel.cs" id="2_8cb7y"]
-[ext_resource type="Script" path="res://Scenes/SettingsController.cs" id="3_a4w6m"]
+[ext_resource type="Script" uid="uid://cmvvubxfvdca7" path="res://Scripts/Main.cs" id="1_k1i8e"]
+[ext_resource type="Script" uid="uid://d3cbk8f7lckbr" path="res://Scenes/FPSLabel.cs" id="2_8cb7y"]
+[ext_resource type="Script" uid="uid://dxmkbb5f1t368" path="res://Scenes/SettingsController.cs" id="3_a4w6m"]
+[ext_resource type="Script" uid="uid://52grhydeyy0t" path="res://Scenes/PerfDetails.cs" id="3_u2p48"]
 
 [node name="Main" type="Node2D"]
 script = ExtResource("1_k1i8e")
-BrushSize = 0
-TextureResolution = 0.25
-RainAmount = 5.0
+DebugMode = true
+BrushSize = 4
 
 [node name="CanvasLayer" type="CanvasLayer" parent="."]
 
@@ -34,6 +34,15 @@ text = "FPS: 0
 "
 script = ExtResource("2_8cb7y")
 
+[node name="PerfDetails" type="Label" parent="CanvasLayer/TopUI"]
+layout_mode = 0
+offset_top = 30.0
+offset_right = 76.0
+offset_bottom = 67.0
+theme_override_font_sizes/font_size = 10
+text = "Active Elements: 0"
+script = ExtResource("3_u2p48")
+
 [node name="Settings" type="VBoxContainer" parent="CanvasLayer/TopUI"]
 layout_mode = 1
 anchors_preset = 1
@@ -75,6 +84,13 @@ custom_minimum_size = Vector2(150, 0)
 layout_mode = 2
 size_flags_horizontal = 8
 size_flags_vertical = 1
-max_value = 5.0
+max_value = 10.0
 step = 0.01
 value = 1.0
+
+[node name="ToolbarMarginContainer2" parent="CanvasLayer/TopUI" instance=ExtResource("5_kry3j")]
+layout_mode = 0
+offset_left = 860.0
+offset_top = 5.0
+offset_right = 1060.0
+offset_bottom = 69.0

Scripts/Chunk.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using FOU.Scripts.Elements;
 using Godot;
 
@@ -15,7 +16,9 @@ public class Chunk {
     private readonly Image image;
     private readonly int sizeX;
     private readonly int sizeY;
-    private int frame;
+    private readonly HashSet<Element> activeElements;
+    private readonly HashSet<Element> toAddElements = new();
+    private readonly HashSet<Element> toRemoveElements = new();
 
     public Chunk(int x, int y, int index) {
         Index = index;
@@ -29,46 +32,62 @@ public class Chunk {
             }
         }
 
-        image = Image.Create(sizeX, sizeY, false, Image.Format.Rgb8);
+        activeElements = new HashSet<Element>(sizeX * sizeY);
+
+        image = Image.CreateEmpty(sizeX, sizeY, false, Image.Format.Rgb8);
         image.Fill(Colors.Black);
     }
 
     public void Update() {
-        for (int x = 0; x < sizeX; x++) {
-            for (int y = 0; y < sizeY; y++) {
-                if (Elements[x,y] != null)
-                    Elements[x,y].Update(frame);
+        foreach (Element e in activeElements)
+            e.Update();
+
+        // apply changes:
+        if (toRemoveElements.Count > 0) {
+            foreach (Element removeElement in toRemoveElements) {
+                activeElements.Remove(removeElement);
+                removeElement.ResetColor();
             }
+            toRemoveElements.Clear();
+        }
+
+        if (toAddElements.Count > 0) {
+            foreach (Element addElement in toAddElements) {
+                activeElements.Add(addElement);
+                addElement.SetDebugColor(addElement.Color * 1.5f);
+            }
+            toAddElements.Clear();
         }
-        frame++;
-        // TODO: enable rain again
-        // MakeItRain(_main.RainAmount);
     }
 
-    public void WritePixel<T>(int x, int y, int size) {
-        int halfsize = size/2;
+    public void SetElementActive(Element e, bool active) {
+        if (e.GetType() == typeof(Element)) return;
+
+        if (active) AddToChunk(e);
+        else RemoveFromChunk(e);
+    }
+
+    public void WritePixel<T>(int x, int y) {
+        if (x < 0 || x >= sizeX || y < 0 || y >= sizeY) {
+            GD.PrintErr($"Out of bounds for chunk: {x}:{y}");
+            return;
+        }
 
         Type type = typeof(T);
+        object o = Activator.CreateInstance(type, x, y, this);
 
-        for (int i = -halfsize; i <= halfsize; i++) {
-            for (int j = -halfsize; j <= halfsize; j++) {
-                int X = Mathf.Clamp(x + i, 0, sizeX-1);
-                int Y = Mathf.Clamp(y + j, 0, sizeY-1);
-                object o = Activator.CreateInstance(type, X, Y, this);
-
-                if (Elements[X,Y].GetType() != type)
-                    Elements[X,Y] = o as Element;
-            }
+        // check if not empty and overwrite not allowed:
+        if (!Elements[x,y].IsEmpty() && !Main.Instance.AllowOverwrite) {
+            return;
         }
+
+        Elements[x, y].Chunk.RemoveFromChunk(Elements[x, y]);
+        Elements[x, y] = o as Element;
+        Elements[x, y].Active = true;
     }
 
-    public Image DrawLevel() {
-        for (int x = 0; x < sizeX; x++) {
-            for (int y = 0; y < sizeY; y++) {
-                image.SetPixel(x,y, Elements[x,y].Color);
-            }
-        }
-        return image;
+    public int ActiveElementsCount() {
+        return activeElements.Count;
     }
 
     public void Swap(Element what, Vector2I pos) {
@@ -115,6 +134,15 @@ public class Chunk {
             GD.PrintErr("Trying to swap null");
             return;
         }
+
+        if (what.Chunk != swapTo.Chunk) {
+            what.Chunk.RemoveFromChunk(what);
+            swapTo.Chunk.AddToChunk(what);
+
+            swapTo.Chunk.RemoveFromChunk(swapTo);
+            what.Chunk.AddToChunk(swapTo);
+        }
+
         Element temp = new Element(what);
 
         what.Position = swapTo.Position;
@@ -126,8 +154,20 @@ public class Chunk {
         swapTo.Chunk.Elements[swapTo.Position.X, swapTo.Position.Y] = swapTo;
 
         what.Active = true;
+        what.Moved();
         swapTo.Active = true;
-        what.LastMove = frame;
-        swapTo.LastMove = frame;
+        swapTo.Moved();
+    }
+
+    public override string ToString() {
+        return $"Chunk {Index}";
+    }
+
+    private void RemoveFromChunk(Element e) {
+        toRemoveElements.Add(e);
+    }
+
+    private void AddToChunk(Element e) {
+        toAddElements.Add(e);
     }
 }

Scripts/Chunk.cs.uid

@@ -0,0 +1 @@
+uid://r17upkbkmfiy

Scripts/Elements/Dirt.cs

@@ -5,7 +5,7 @@ namespace FOU.Scripts.Elements;
 public class Dirt : Solid {
 
     public Dirt(int x, int y, ref Chunk chunk) : base(x, y, ref chunk) {
-        Color = AddColorVariance(Colors.Brown);
+        color = AddColorVariance(Colors.Brown);
         Density = 10;
         DiffuseSpeed = 50;
     }

Scripts/Elements/Dirt.cs.uid

@@ -0,0 +1 @@
+uid://80esqy0cardd

Scripts/Elements/Element.cs

@@ -2,83 +2,83 @@
 
 namespace FOU.Scripts.Elements;
 
-public class Element {
-    public Color Color = Colors.Black;
+public class Element{
 
-    public Vector2I Position;
     public Chunk Chunk;
+    public Vector2I Position;
     public int Density;
-    public int LastUpdate = -1;
-    public int LastMove = 0;
 
-    public int DiffuseSpeed = 10;
-    public const int MAX_DIFFUSE_SPEED = 100;
-    public const int STEPS_UNTIL_INACTIVE = 100;
+    protected int DiffuseSpeed = 10;
+    protected Color color = Colors.Black;
+    protected const int MAX_DIFFUSE_SPEED = 100;
+    protected const int STEPS_UNTIL_INACTIVE = 500;
 
-    protected const float MAX_COLOR_VARIANCE = 0.1f;
     protected static readonly Vector2I VERTICAL_OPPOSITE = new Vector2I(-1, 1);
+    private const float MAX_COLOR_VARIANCE = 0.1f;
 
-    private bool active = true;
+    private bool active = false;
+    private bool markedForUpdate = true;
+    private int lastUpdate = -1;
+    private int lastMove = 0;
     private Color originalColor;
 
     public Element(Element e) {
         Position = e.Position;
         Chunk = e.Chunk;
+        Active = e.active;
+        lastMove = e.lastMove;
+        lastUpdate = e.lastUpdate;
+        Chunk.SetElementActive(this, Active);
     }
 
     public Element(int x, int y, Chunk chunk) {
         Position.X = x;
         Position.Y = y;
         Chunk = chunk;
+        lastMove = Engine.GetFramesDrawn();
+        Chunk.SetElementActive(this, Active);
     }
 
     public bool Active {
         get => active;
         set {
+            if (active == value) return;
             active = value;
+            Chunk.SetElementActive(this, value);
 
-            if (active)
-                Color = originalColor;
-            else if (Main.Instance.DebugVisualization)
-                Color = new Color(0.2f, 0.2f, 0.2f);
+            if (active) {
+                Moved();
+            } else {
+                ResetColor();
+            }
         }
     }
 
+    public Color Color => color;
+
     /// <summary>
     /// base update method, checks if anything is to do at all
     /// </summary>
     /// <param name="currentFrame"></param>
     /// <returns>false if there is nothing to do</returns>
-    public virtual bool Update(int currentFrame) {
+    public virtual bool Update() {
         if (!Active) return false;
 
-        if (LastUpdate == currentFrame) return false; // already updated this frame
-        LastUpdate = currentFrame;
+        int frame = Engine.GetFramesDrawn();
+        if (lastMove + STEPS_UNTIL_INACTIVE < frame)
+            Active = false;
+        if (lastUpdate == frame)
+            return false; // already updated this frame
 
+        lastUpdate = frame;
         return true;
     }
 
     public override string ToString() {
-        return $"{GetType()} {Position}[{Chunk.Index}]";
+        return $"{GetType()} {Position}[{Chunk.Index}] {active}";
     }
 
-    protected virtual void Tick() {
-        Vector2I randomDirection = RandomDirectionDown();
-
-        if (Chunk.IsEmpty(Position + Vector2I.Down))
-            Chunk.Swap(this, Position + Vector2I.Down);
-
-        else if (Chunk.IsEmpty(Position + randomDirection))
-            Chunk.Swap(this, Position + randomDirection);
-
-        else if (Chunk.IsEmpty(Position + randomDirection * VERTICAL_OPPOSITE))
-            Chunk.Swap(this, Position + randomDirection * VERTICAL_OPPOSITE);
-
-        if (GD.Randi() % MAX_DIFFUSE_SPEED > DiffuseSpeed) return; // ascend slower
-
-        if (Chunk.Get(Position + randomDirection)?.Density < Density)
-            Chunk.Swap(this, Position + Vector2I.Down);
-    }
+    protected virtual void Tick() { }
 
     protected Vector2I RandomDirectionDown() {
         int randomDirection = GD.Randi() % 2 != 0 ? 1 : -1;
@@ -87,6 +87,13 @@ public class Element {
             + (GD.Randi() % 2 != 0 ? Vector2I.Zero : Vector2I.Right * randomDirection);
     }
 
+    /// <returns>-1, 0 or 1</returns>
+    protected Vector2I RandomDirection() {
+        int randomDirection = GD.Randi() % 2 != 0 ? 1 : -1;
+
+        return (GD.Randi() % 2 != 0 ? Vector2I.Zero : Vector2I.Right * randomDirection);
+    }
+
     protected Color AddColorVariance(Color baseColor) {
         Color c = baseColor;
         c.R += (GD.Randf() - 1) * MAX_COLOR_VARIANCE;
@@ -97,4 +104,31 @@ public class Element {
         return c;
     }
 
+    public void ResetColor() {
+        color = originalColor;
+        MarkForUpdate();
+    }
+
+    public void SetDebugColor(Color color) {
+        if (!Main.Instance.DebugMode) return;
+
+        this.color = color;
+    }
+
+    public void Moved() {
+        lastMove = Engine.GetFramesDrawn();
+        MarkForUpdate();
+    }
+
+    public bool IsMarkedForUpdate() {
+        return markedForUpdate;
+    }
+
+    public void MarkForUpdate(bool mark = true) {
+        markedForUpdate = true;
+    }
+
+    public bool IsEmpty() {
+        return GetType() == typeof(Element);
+    }
 }

Scripts/Elements/Element.cs.uid

@@ -0,0 +1 @@
+uid://b5lme1c4rx15n

Scripts/Elements/Liquid.cs

@@ -5,18 +5,19 @@ namespace FOU.Scripts.Elements;
 public abstract class Liquid : Element {
     public const int MAX_VERTICAL_SPREAD = 3;
 
-    protected Liquid(int x, int y, ref Chunk chunk) : base(x, y, chunk) { }
+    protected Liquid(int x, int y, ref Chunk chunk) : base(x, y, chunk) {
+        MarkForUpdate();
+    }
 
-    public override bool Update(int currentFrame) {
-        if (!base.Update(currentFrame)) return false;
-        if (LastMove + STEPS_UNTIL_INACTIVE < currentFrame) Active = false;
+    public override bool Update() {
+        if (!base.Update()) return false;
 
         Tick();
 
         return true; // not necessarily end, subclasses could do some more things
     }
 
-    protected override void Tick() {
+    protected virtual void Tick() {
         Vector2I randomDirection = RandomDirectionDown();
         if (randomDirection.Y != 0)
             randomDirection *= Vector2I.Left * (int)(GD.Randi() % MAX_VERTICAL_SPREAD);

Scripts/Elements/Liquid.cs.uid

@@ -0,0 +1 @@
+uid://bqx36wisy7127

Scripts/Elements/Solid.cs

@@ -3,14 +3,40 @@
 namespace FOU.Scripts.Elements;
 
 public abstract class Solid : Element {
-    protected Solid(int x, int y, ref Chunk chunk) : base(x, y, chunk) { }
+    protected Solid(int x, int y, ref Chunk chunk) : base(x, y, chunk) {
+        MarkForUpdate();
+    }
 
-    public override bool Update(int currentFrame) {
-        if (!base.Update(currentFrame)) return false;
-        if (LastMove + STEPS_UNTIL_INACTIVE < currentFrame) Active = false;
+    public override bool Update() {
+        if (!base.Update()) return false;
 
         Tick();
 
         return true; // not necessarily end, subclasses could do some more things
     }
+
+    protected virtual void Tick() {
+        Vector2I randomDirection = RandomDirectionDown();
+
+        // fall speed reduction:
+        if (GD.Randi() % MAX_DIFFUSE_SPEED > DiffuseSpeed) return; // descend slower
+
+        if (Chunk.IsEmpty(Position + Vector2I.Down))
+            Chunk.Swap(this, Position + Vector2I.Down);
+
+        else if (Chunk.IsEmpty(Position + Vector2I.Down + randomDirection))
+            Chunk.Swap(this, Position + Vector2I.Down + randomDirection);
+
+        else if (Chunk.IsEmpty(Position + Vector2I.Down + randomDirection * VERTICAL_OPPOSITE))
+            Chunk.Swap(this, Position + Vector2I.Down + randomDirection * VERTICAL_OPPOSITE);
+
+        // density check
+        if (Chunk.Get(Position + Vector2I.Down)?.Density < Density)
+            Chunk.Swap(this, Position + Vector2I.Down);
+        else if (Chunk.Get(Position + Vector2I.Down + randomDirection)?.Density < Density)
+            Chunk.Swap(this, Position + Vector2I.Down + randomDirection);
+        else if (Chunk.Get(Position + Vector2I.Down + randomDirection * VERTICAL_OPPOSITE)?.Density < Density)
+            Chunk.Swap(this, Position + Vector2I.Down + randomDirection * VERTICAL_OPPOSITE);
+    }
+
 }

Scripts/Elements/Solid.cs.uid

@@ -0,0 +1 @@
+uid://ur56t06r7n4l

Scripts/Elements/Water.cs

@@ -5,7 +5,7 @@ namespace FOU.Scripts.Elements;
 public class Water : Liquid {
 
     public Water(int x, int y, ref Chunk chunk) : base(x, y, ref chunk) {
-        Color = AddColorVariance(Colors.Blue);
+        color = AddColorVariance(Colors.Blue);
         Density = 1;
     }
 

Scripts/Elements/Water.cs.uid

@@ -0,0 +1 @@
+uid://k8id5egjc7x8

Scripts/Level.cs

@@ -1,4 +1,6 @@
-using Godot;
+using System;
+using FOU.Scripts.Elements;
+using Godot;
 
 namespace FOU.Scripts;
 
@@ -9,73 +11,164 @@ public class Level {
     private Chunk[,] chunks;
     private Image image;
 
-    private int chunksX;
-    private int chunksY;
+    private int chunksPerX;
+    private int chunksPerY;
 
     // per chunk:
     private int chunkResX;
     private int chunkResY;
 
+    private float rainAmount = 0;
+
     public Level(Main main, int sizeX, int sizeY) {
-        GD.Print($"Generating level ({sizeX}:{sizeY}) with {chunksX*chunksY} chunks ({chunkResX} * {chunkResY})");
-
         Resolution = new Vector2I(sizeX, sizeY);
-        chunksX = main.ChunksPerAxis;
-        chunksY = main.ChunksPerAxis;
+        chunksPerX = main.ChunksPerAxis;
+        chunksPerY = main.ChunksPerAxis;
 
-        chunkResX = sizeX / chunksX;
-        chunkResY = sizeY / chunksY;
+        chunkResX = sizeX / chunksPerX;
+        chunkResY = sizeY / chunksPerY;
 
-        image = Image.Create(sizeX, sizeY, false, Image.Format.Rgb8);
+        GD.Print($"Generating level ({sizeX}:{sizeY}) with {chunksPerX*chunksPerY} chunks ({chunkResX} * {chunkResY})");
 
-        chunks = new Chunk[chunksX, chunksY];
+        image = Image.CreateEmpty(sizeX, sizeY, false, Image.Format.Rgb8);
+
+        chunks = new Chunk[chunksPerX, chunksPerY];
         int index = 0;
         // create all chunks
-        for (int x = 0; x < chunksX; x++) {
-            for (int y = 0; y < chunksY; y++) {
+        for (int x = 0; x < chunksPerX; x++) {
+            for (int y = 0; y < chunksPerY; y++) {
                 chunks[x, y] = new Chunk(chunkResX, chunkResY, index++);
             }
         }
 
         // assign neighbors
-        for (int x = 0; x < chunksX; x++) {
-            for (int y = 0; y < chunksY; y++) {
+        for (int x = 0; x < chunksPerX; x++) {
+            for (int y = 0; y < chunksPerY; y++) {
 
                 if (y > 0) chunks[x, y].NeighborN = chunks[x, y-1];
-                if (y < chunksY-1) chunks[x, y].NeighborS = chunks[x, y+1];
+                if (y < chunksPerY-1) chunks[x, y].NeighborS = chunks[x, y+1];
 
                 if (x > 0) chunks[x, y].NeighborE = chunks[x-1, y];
-                if (x < chunksX-1) chunks[x, y].NeighborW = chunks[x+1, y];
+                if (x < chunksPerX-1) chunks[x, y].NeighborW = chunks[x+1, y];
             }
         }
     }
 
     public void Update() {
+        MakeItRain();
+
         foreach (Chunk c in chunks)
             c.Update();
     }
 
-    // TODO!
-    private void MakeItRain(float rainAmount) {
-        // int rainDrops = (int)Math.Round(rainAmount);
-        //
-        // for (int i = 0; i <= rainDrops; i++) {
-        //     if (GD.Randf() < rainAmount)
-        //         WritePixel<Water>((int)(GD.Randi() % SizeX), 0, 1);
-        // }
+    public void SetRainAmount(float amount) {
+        rainAmount = amount;
+    }
+
+    public void StartBenchmark() {
+        GD.Print("benchmark");
+        for (int x = 0; x < chunksPerX; x++) {
+            for (int y = 0; y < chunksPerY; y++) {
+                WritePixel<Dirt>((x * chunkResX) + chunkResX/2, (y * chunkResY) + chunkResY/2, 100);
+            }
+        }
+    }
+
+    public Chunk[,] GetChunks() {
+        return chunks;
+    }
+
+    private void MakeItRain() {
+        if (rainAmount < .1f) return;
+
+        int rainDrops = (int)Math.Round(rainAmount);
+
+        for (int i = 0; i <= rainDrops; i++) {
+            if (GD.Randf() < rainAmount) {
+                int d = (int)(GD.Randi() % (chunkResX * chunksPerX));
+                if (GetElement(d, 0).IsEmpty())
+                    WritePixel<Water>(d, 0, 1);
+            }
+        }
     }
 
     public void WritePixel<T>(int x, int y, int size) {
-        chunks[x/chunkResX, y/chunkResY].WritePixel<T>(x % chunkResX, y % chunkResY, size);
+        int halfsize = size/2;
+
+        int startPtX = x % chunkResX;
+        int startPtY = y % chunkResY;
+
+        for (int i = -halfsize; i <= halfsize; i++) {
+            for (int j = -halfsize; j <= halfsize; j++) {
+
+                // calculate in-chunk coordinates
+                int iteratorX = i;
+                int iteratorY = j;
+                int ptX = startPtX;
+                int ptY = startPtY;
+
+                // calculate chunk to write to
+                int chunkX = x/chunkResX;
+
+                // left of chunk
+                if (startPtX + iteratorX < 0) {
+                    chunkX--;
+                    iteratorX = chunkResX + startPtX + iteratorX;
+                    ptX = startPtX + iteratorX;
+
+                } else {
+                    ptX = startPtX + iteratorX;
+                }
+                if (startPtX + iteratorX >= chunkResX) {
+                    chunkX++;
+                    ptX = startPtX + iteratorX - chunkResX;
+                }
+                int chunkY = y/chunkResY;
+
+                // above chunk
+                if (startPtY + iteratorY < 0) {
+                    chunkY--;
+                    ptY = chunkResY + (startPtY + iteratorY);
+                } else {
+                    ptY = startPtY + iteratorY;
+                }
+                if (startPtY + iteratorY >= chunkResY) {
+                    chunkY++;
+                    ptY = startPtY + iteratorY - chunkResY;
+                }
+
+                // ignore everything outside
+                if (chunkX < 0) continue;
+                if (chunkX >= chunksPerX) continue;
+                if (chunkY < 0) continue;
+                if (chunkY >= chunksPerY) continue;
+
+                chunks[chunkX, chunkY].WritePixel<T>(ptX, ptY);
+            }
+        }
+    }
+
+    public Element GetElement(int x, int y) {
+        if (x < 0 || x > chunkResX * chunkResX) return null;
+        if (y < 0 || y > chunkResY * chunkResY) return null;
+
+        return chunks[x / chunkResX, y / chunkResY].Elements[x % chunkResX, y % chunkResY];
     }
 
     public Image DrawLevel() {
-        for (int cx = 0; cx < chunksX; cx++) {
-            for (int cy = 0; cy < chunksY; cy++) {
+        // chunk
+        for (int cx = 0; cx < chunksPerX; cx++) {
+            for (int cy = 0; cy < chunksPerY; cy++) {
 
+                // pixel in chunk
                 for (int x = 0; x < chunkResX; x++) {
                     for (int y = 0; y < chunkResY; y++) {
-                        image.SetPixel(cx*chunkResX + x, cy*chunkResY + y, chunks[cx,cy].Elements[x, y].Color);
+                        // TODO: multithreading here! use Chunk.DrawLevel() and stitch images together
+
+                        if (chunks[cx, cy].Elements[x, y].IsMarkedForUpdate()) {
+                            image.SetPixel(cx * chunkResX + x, cy * chunkResY + y, chunks[cx, cy].Elements[x, y].Color);
+                            chunks[cx, cy].Elements[x, y].MarkForUpdate(false);
+                        }
                     }
                 }
             }

Scripts/Level.cs.uid

@@ -0,0 +1 @@
+uid://bkwbjagt8s01s

Scripts/Main.cs

@@ -1,32 +1,47 @@
-using System.Reflection;
 using FOU.Scripts;
 using FOU.Scripts.Elements;
 using Godot;
 
 public partial class Main : Node2D {
-	[Export] public bool DebugVisualization = false;
+	[Export] public bool DebugMode = false;
+	[Export] public bool AllowOverwrite = true;
 
 	[Export] public int BrushSize = 5;
 	[Export] public float TextureResolution = 0.5f;
 	[Export] public int ChunksPerAxis = 2;
-	[Export] public float RainAmount = 0.01f;
+	[Export] public float rainAmount = 0;
 
 	public static Main Instance;
+	public Level Level;
 
 	private TextureRect mLevelDrawer;
-	private Level mLevel;
+	private bool enableRain;
+
+	public float RainAmount {
+		get => rainAmount;
+		set {
+			rainAmount = value;
+			Level?.SetRainAmount(rainAmount);
+		}
+	}
 
 	public override void _Ready() {
-		mLevel = new Level(this, (int)(GetViewportRect().Size.X * TextureResolution),
+		Level = new Level(this, (int)(GetViewportRect().Size.X * TextureResolution),
 								 (int)(GetViewportRect().Size.Y * TextureResolution));
+		Level.SetRainAmount(rainAmount);
 		mLevelDrawer = GetNode<TextureRect>("CanvasLayer/LevelDrawer");
 
 		Instance = this;
 	}
 
+	public override void _PhysicsProcess(double delta) {
+		base._PhysicsProcess(delta);
+	}
+
 	public override void _Process(double delta) {
-		mLevel.Update();
-		mLevelDrawer.Texture = ImageTexture.CreateFromImage(mLevel.DrawLevel());
+		Level.Update();
+		mLevelDrawer.Texture?.Dispose();
+		mLevelDrawer.Texture = ImageTexture.CreateFromImage(Level.DrawLevel());
 	}
 
 	public override void _UnhandledInput(InputEvent @event) {
@@ -35,11 +50,15 @@ public partial class Main : Node2D {
 			if (eventMouseButton.IsPressed()) {
 				Vector2 mouse = GetViewport().GetMousePosition();
 
-				float mappedX = mouse.X / (GetViewportRect().Size.X / mLevel.Resolution.X);
-				float mappedY = mouse.Y / (GetViewportRect().Size.Y / mLevel.Resolution.Y);
+				float mappedX = mouse.X / (GetViewportRect().Size.X / Level.Resolution.X);
+				float mappedY = mouse.Y / (GetViewportRect().Size.Y / Level.Resolution.Y);
 
-				mLevel.WritePixel<Dirt>((int)mappedX, (int)mappedY, BrushSize);
+				Level.WritePixel<Dirt>((int)mappedX, (int)mappedY, BrushSize);
 			}
-		} else base._UnhandledInput(@event);
+		} else if (@event is InputEventKey keyEvent && keyEvent.Pressed) {
+			if (keyEvent.Keycode == Key.F9)
+				Level.StartBenchmark();
+		}
+		else base._UnhandledInput(@event);
 	}
 }

Scripts/Main.cs.uid

@@ -0,0 +1 @@
+uid://cmvvubxfvdca7

benchmark.txt

@@ -0,0 +1,22 @@
+# Benchmark
+
+Start from editor not rider!
+
+## Settings
+
+- Texture Resolution: 0.5
+- CHunks per Axis: 2
+- Rain Amount: 0
+
+## Measurements:
+
+### original (no optimization):
+
+- idle: 42 - 44 fps
+- benchmark: 24 fps minimum
+
+### performance-improvements (71db6513f22094e7dd67bd32c7ab86b326f9ad9e)
+
+- idle before: 89
+- benchmark: 33
+- idle after: 75

project.godot

@@ -12,7 +12,7 @@ config_version=5
 
 config/name="FOU"
 run/main_scene="res://Scenes/main.tscn"
-config/features=PackedStringArray("4.2", "C#", "Forward Plus")
+config/features=PackedStringArray("4.5", "C#", "Forward Plus")
 config/icon="res://icon.svg"
 
 [dotnet]