Initial commit

src/LargeGridPathfinding.sln

@@ -0,0 +1,22 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.12.35707.178
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "LargeGridPathfinding", "LargeGridPathfinding\LargeGridPathfinding.csproj", "{4F58A5EA-B389-4AFE-979C-0F0B0AAAD86C}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{4F58A5EA-B389-4AFE-979C-0F0B0AAAD86C}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4F58A5EA-B389-4AFE-979C-0F0B0AAAD86C}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4F58A5EA-B389-4AFE-979C-0F0B0AAAD86C}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4F58A5EA-B389-4AFE-979C-0F0B0AAAD86C}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+EndGlobal

src/LargeGridPathfinding/.config/dotnet-tools.json

@@ -0,0 +1,36 @@
+{
+  "version": 1,
+  "isRoot": true,
+  "tools": {
+    "dotnet-mgcb": {
+      "version": "3.8.2.1105",
+      "commands": [
+        "mgcb"
+      ]
+    },
+    "dotnet-mgcb-editor": {
+      "version": "3.8.2.1105",
+      "commands": [
+        "mgcb-editor"
+      ]
+    },
+    "dotnet-mgcb-editor-linux": {
+      "version": "3.8.2.1105",
+      "commands": [
+        "mgcb-editor-linux"
+      ]
+    },
+    "dotnet-mgcb-editor-windows": {
+      "version": "3.8.2.1105",
+      "commands": [
+        "mgcb-editor-windows"
+      ]
+    },
+    "dotnet-mgcb-editor-mac": {
+      "version": "3.8.2.1105",
+      "commands": [
+        "mgcb-editor-mac"
+      ]
+    }
+  }
+}

src/LargeGridPathfinding/Agent.cs

@@ -0,0 +1,19 @@
+using Microsoft.Xna.Framework;
+
+using System;
+using System.Collections.Generic;
+
+namespace LargeGridPathfinding;
+
+internal class Agent(Vector2 position)
+{
+    public Vector2 Position { get; set; } = position;
+
+    public Point GridPosition => new Point((int)Math.Round(Position.X), (int)Math.Round(Position.Y));
+
+    public Vector2 NextPosition { get; set; }
+
+    public Point? Destination { get; set; }
+
+    public List<Vector2>? Path { get; set; }
+}

src/LargeGridPathfinding/Content/Content.mgcb

@@ -0,0 +1,22 @@
+
+#----------------------------- Global Properties ----------------------------#
+
+/outputDir:bin/$(Platform)
+/intermediateDir:obj/$(Platform)
+/platform:DesktopGL
+/config:
+/profile:Reach
+/compress:False
+
+#-------------------------------- References --------------------------------#
+
+
+#---------------------------------- Content ---------------------------------#
+
+#begin File1.spritefont
+/importer:FontDescriptionImporter
+/processor:FontDescriptionProcessor
+/processorParam:PremultiplyAlpha=True
+/processorParam:TextureFormat=Compressed
+/build:File1.spritefont;ManoloMono.spritefont
+

src/LargeGridPathfinding/Content/File.spritefont

@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+This file contains an xml description of a font, and will be read by the XNA
+Framework Content Pipeline. Follow the comments to customize the appearance
+of the font in your game, and to change the characters which are available to draw
+with.
+-->
+<XnaContent xmlns:Graphics="Microsoft.Xna.Framework.Content.Pipeline.Graphics">
+  <Asset Type="Graphics:FontDescription">
+
+    <!--
+    Modify this string to change the font that will be imported.
+    -->
+    <FontName>Arial</FontName>
+
+    <!--
+    Size is a float value, measured in points. Modify this value to change
+    the size of the font.
+    -->
+    <Size>12</Size>
+
+    <!--
+    Spacing is a float value, measured in pixels. Modify this value to change
+    the amount of spacing in between characters.
+    -->
+    <Spacing>0</Spacing>
+
+    <!--
+    UseKerning controls the layout of the font. If this value is true, kerning information
+    will be used when placing characters.
+    -->
+    <UseKerning>true</UseKerning>
+
+    <!--
+    Style controls the style of the font. Valid entries are "Regular", "Bold", "Italic",
+    and "Bold, Italic", and are case sensitive.
+    -->
+    <Style>Regular</Style>
+
+    <!--
+    If you uncomment this line, the default character will be substituted if you draw
+    or measure text that contains characters which were not included in the font.
+    -->
+    <!-- <DefaultCharacter>*</DefaultCharacter> -->
+
+    <!--
+    CharacterRegions control what letters are available in the font. Every
+    character from Start to End will be built and made available for drawing. The
+    default range is from 32, (ASCII space), to 126, ('~'), covering the basic Latin
+    character set. The characters are ordered according to the Unicode standard.
+    See the documentation for more information.
+    -->
+    <CharacterRegions>
+      <CharacterRegion>
+        <Start>&#32;</Start>
+        <End>&#126;</End>
+      </CharacterRegion>
+    </CharacterRegions>
+  </Asset>
+</XnaContent>

src/LargeGridPathfinding/Content/File1.spritefont

@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+This file contains an xml description of a font, and will be read by the XNA
+Framework Content Pipeline. Follow the comments to customize the appearance
+of the font in your game, and to change the characters which are available to draw
+with.
+-->
+<XnaContent xmlns:Graphics="Microsoft.Xna.Framework.Content.Pipeline.Graphics">
+  <Asset Type="Graphics:FontDescription">
+
+    <!--
+    Modify this string to change the font that will be imported.
+    -->
+    <FontName>ManoloMono</FontName>
+
+    <!--
+    Size is a float value, measured in points. Modify this value to change
+    the size of the font.
+    -->
+    <Size>12</Size>
+
+    <!--
+    Spacing is a float value, measured in pixels. Modify this value to change
+    the amount of spacing in between characters.
+    -->
+    <Spacing>0</Spacing>
+
+    <!--
+    UseKerning controls the layout of the font. If this value is true, kerning information
+    will be used when placing characters.
+    -->
+    <UseKerning>true</UseKerning>
+
+    <!--
+    Style controls the style of the font. Valid entries are "Regular", "Bold", "Italic",
+    and "Bold, Italic", and are case sensitive.
+    -->
+    <Style>Regular</Style>
+
+    <!--
+    If you uncomment this line, the default character will be substituted if you draw
+    or measure text that contains characters which were not included in the font.
+    -->
+    <!-- <DefaultCharacter>*</DefaultCharacter> -->
+
+    <!--
+    CharacterRegions control what letters are available in the font. Every
+    character from Start to End will be built and made available for drawing. The
+    default range is from 32, (ASCII space), to 126, ('~'), covering the basic Latin
+    character set. The characters are ordered according to the Unicode standard.
+    See the documentation for more information.
+    -->
+    <CharacterRegions>
+      <CharacterRegion>
+        <Start>&#32;</Start>
+        <End>&#126;</End>
+      </CharacterRegion>
+    </CharacterRegions>
+  </Asset>
+</XnaContent>

src/LargeGridPathfinding/GridFiller.cs

@@ -0,0 +1,297 @@
+using Microsoft.Xna.Framework;
+
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace LargeGridPathfinding;
+
+internal class GridFiller
+{
+    private int currentLabel = 1;
+    private int currentObstacleLabel = -1;
+    public int[,] Grid { get; }
+    public ConcurrentDictionary<int, Rectangle> PlacedRectangles { get; }
+    public int Width { get; }
+    public int Height { get; }
+
+    public GridFiller(int width, int height, List<Rectangle> obstacles)
+    {
+        Width = width;
+        Height = height;
+        Grid = new int[height, width];
+        PlacedRectangles = [];
+
+        foreach (Rectangle rectangle in obstacles)
+        {
+            PlaceObstacle(rectangle);
+        }
+    }
+
+    public void FillGrid(int? x1 = null, int? y1 = null, int? x2 = null, int? y2 = null, bool fillAll = false, IProgress<float>? totalProgress = null, IProgress<float>? calculatingCandidatesProgress = null, IProgress<float>? placingCandidatesProgress = null)
+    {
+        x1 ??= 0;
+        y1 ??= 0;
+        x2 ??= Width;
+        y2 ??= Height;
+
+        if (fillAll)
+        {
+            PlacedRectangles.Clear();
+            for (int y = y1.Value; y < y2; y++)
+            {
+                for (int x = x1.Value; x < x2; x++)
+                {
+                    if (Grid[y, x] > 0)
+                    {
+                        Grid[y, x] = 0;
+                    }
+                }
+            }
+        }
+
+        // Collect all valid rectangle placements
+        ConcurrentBag<(int x, int y, int w, int h)> candidates = [];
+
+        int cells = Grid.GetLength(0) * Grid.GetLength(1);
+        int areaPlaced = 0;
+        int maxRectangleSize = Math.Max((Grid.GetLength(0) + Grid.GetLength(1)) / 20, 100);
+        int reportInterval = cells / 100;
+
+        do
+        {
+            candidates.Clear();
+
+            Debug.WriteLine("Calculating candidates...");
+
+            // Calculate all possible rectangle placements
+            _ = Parallel.For(y1.Value, y2.Value, (y, loopState) =>
+            {
+                for (int x = x1.Value; x < x2; x++)
+                {
+                    if (Grid[y, x] == 0)
+                    {
+                        (int w, int h) = GetMaxRectangleSize(x, y, maxRectangleSize, maxRectangleSize);
+
+                        if (w > 0 && h > 0)
+                        {
+                            candidates.Add((x, y, w, h));
+                        }
+
+                        if (w >= maxRectangleSize && h >= maxRectangleSize)
+                        {
+                            loopState.Break();
+                            return;
+                        }
+
+                        if (candidates.Count % reportInterval == 0)
+                        {
+                            calculatingCandidatesProgress?.Report((float)candidates.Count / (cells - areaPlaced));
+                            Debug.WriteLine($"Candidates Progress: {candidates.Count} / {cells - areaPlaced} ({(float)candidates.Count / (cells - areaPlaced):P2})");
+                        }
+                    }
+                }
+            });
+
+            Debug.WriteLine($"Candidates: {candidates.Count}");
+            Debug.WriteLine("Sorting candidates...");
+
+            // Sort by area (largest first)
+            List<(int x, int y, int w, int h)> sortedCandidates = [.. candidates];
+            sortedCandidates.Sort((a, b) => (b.w * b.h).CompareTo(a.w * a.h));
+
+            Debug.WriteLine("Placing rectangles...");
+
+            int placed = 0;
+            int reportIntervalPlacing = Math.Max(sortedCandidates.Count / 10, 1);
+
+            // Place rectangles, ensuring no overlap
+            foreach ((int x, int y, int w, int h) in sortedCandidates)
+            {
+                // Check if area is still free
+                if (IsAreaFree(x, y, w, h))
+                {
+                    Rectangle rectangle = new Rectangle(x, y, w, h);
+                    PlaceRectangle(rectangle);
+                    areaPlaced += w * h;
+                }
+
+                placed++;
+
+                if (placed % reportIntervalPlacing == 0)
+                {
+                    totalProgress?.Report((float)areaPlaced / cells);
+                    placingCandidatesProgress?.Report((float)placed / (sortedCandidates.Count + 1));
+                    Debug.WriteLine($"Placed Progress: {placed} / {sortedCandidates.Count} ({(float)placed / sortedCandidates.Count:P2})");
+                }
+            }
+
+            totalProgress?.Report((float)areaPlaced / cells);
+        } while (!candidates.IsEmpty);
+
+        totalProgress?.Report(1);
+        calculatingCandidatesProgress?.Report(1);
+        placingCandidatesProgress?.Report(1);
+    }
+
+    public void PlaceObstacle(Rectangle rectangle)
+    {
+        // Check area around the rectangle to update all adjacent rectangles
+
+        int y = int.Clamp(rectangle.Y - 1, 0, Height);
+        int x = int.Clamp(rectangle.X - 1, 0, Width);
+        int h = int.Clamp(rectangle.Y + rectangle.Height + 2, 0, Height);
+        int w = int.Clamp(rectangle.X + rectangle.Width + 2, 0, Width);
+
+        List<Rectangle> removedRectangles = [new Rectangle(x, y, w - x, h - y)];
+
+        int obstacle = currentObstacleLabel--;
+
+        for (int dy = y; dy < h; dy++)
+        {
+            for (int dx = x; dx < w; dx++)
+            {
+                if (Grid[dy, dx] > 0 && PlacedRectangles.ContainsKey(Grid[dy, dx]))
+                {
+                    removedRectangles.Add(RemoveRectangle(Grid[dy, dx]));
+                }
+
+                if (Grid[dy, dx] >= 0 && dy < rectangle.Y + rectangle.Height && dx < rectangle.X + rectangle.Width && dy >= rectangle.Y && dx >= rectangle.X)
+                {
+                    Grid[dy, dx] = obstacle;
+                }
+            }
+        }
+
+        if (removedRectangles.Count == 1)
+        {
+            return;
+        }
+
+        int minStartX = removedRectangles.Min(r => r.X);
+        int minStartY = removedRectangles.Min(r => r.Y);
+        int maxEndX = removedRectangles.Max(r => r.X + r.Width);
+        int maxEndY = removedRectangles.Max(r => r.Y + r.Height);
+
+        FillGrid(minStartX, minStartY, maxEndX, maxEndY);
+
+        Debug.WriteLine("Placed obstacle");
+        Debug.WriteLine($"Placed obstacle {rectangle.X}, {rectangle.Y}, {rectangle.Width}, {rectangle.Height}");
+        Debug.WriteLine($"minX: {minStartX}, minY: {minStartY}, maxX: {maxEndX}, maxY: {maxEndY}");
+    }
+
+    public void RemoveObstacle(Rectangle rectangle)
+    {
+        // Check area around the rectangle to update all adjacent rectangles
+
+        int y = int.Clamp(rectangle.Y - 1, 0, Height);
+        int x = int.Clamp(rectangle.X - 1, 0, Width);
+        int h = int.Clamp(rectangle.Y + rectangle.Height + 2, 0, Height);
+        int w = int.Clamp(rectangle.X + rectangle.Width + 2, 0, Width);
+
+        List<Rectangle> removedRectangles = [new Rectangle(x, y, w - x, h - y)];
+
+        for (int dy = y; dy < h; dy++)
+        {
+            for (int dx = x; dx < w; dx++)
+            {
+                if (Grid[dy, dx] > 0)
+                {
+                    removedRectangles.Add(RemoveRectangle(Grid[dy, dx]));
+                }
+
+                if (Grid[dy, dx] < 0 && dy < rectangle.Y + rectangle.Height && dx < rectangle.X + rectangle.Width && dy >= rectangle.Y && dx >= rectangle.X)
+                {
+                    Grid[dy, dx] = 0;
+                }
+            }
+        }
+
+        int minStartX = removedRectangles.Min(r => r.X);
+        int minStartY = removedRectangles.Min(r => r.Y);
+        int maxEndX = removedRectangles.Max(r => r.X + r.Width);
+        int maxEndY = removedRectangles.Max(r => r.Y + r.Height);
+
+        FillGrid(minStartX, minStartY, maxEndX, maxEndY);
+
+        Debug.WriteLine("Removed obstacle");
+        Debug.WriteLine($"Placed obstacle {rectangle.X}, {rectangle.Y}, {rectangle.Width}, {rectangle.Height}");
+        Debug.WriteLine($"minX: {minStartX}, minY: {minStartY}, maxX: {maxEndX}, maxY: {maxEndY}");
+    }
+
+    // Helper method to check if a rectangle can still be placed
+    private bool IsAreaFree(int x, int y, int w, int h)
+    {
+        for (int dy = 0; dy < h; dy++)
+        {
+            for (int dx = 0; dx < w; dx++)
+            {
+                if (Grid[y + dy, x + dx] != 0) // Not empty
+                {
+                    return false;
+                }
+            }
+        }
+        return true;
+    }
+
+    private (int, int) GetMaxRectangleSize(int startX, int startY, int limitW, int limitH)
+    {
+        int maxWidth = 0, maxHeight = 0;
+
+        for (int x = startX; x < Width && maxWidth < limitW && Grid[startY, x] == 0; x++)
+        {
+            maxWidth++;
+        }
+
+        for (int h = 1; h <= Math.Min(Height - startY, limitH); h++)
+        {
+            for (int x = startX; x < startX + maxWidth; x++)
+            {
+                if (Grid[startY + h - 1, x] != 0)
+                {
+                    return (maxWidth, h - 1);
+                }
+            }
+            maxHeight = h;
+        }
+
+        return (maxWidth, maxHeight);
+    }
+
+    private void PlaceRectangle(Rectangle rectangle)
+    {
+        int label = currentLabel++;
+
+        for (int dy = 0; dy < rectangle.Height; dy++)
+        {
+            for (int dx = 0; dx < rectangle.Width; dx++)
+            {
+                Grid[rectangle.Y + dy, rectangle.X + dx] = label;
+            }
+        }
+
+        PlacedRectangles[label] = rectangle;
+    }
+
+    private Rectangle RemoveRectangle(int label)
+    {
+        if (!PlacedRectangles.TryRemove(label, out Rectangle rectangle))
+        {
+            return Rectangle.Empty;
+        }
+
+        for (int dy = 0; dy < rectangle.Height; dy++)
+        {
+            for (int dx = 0; dx < rectangle.Width; dx++)
+            {
+                Grid[rectangle.Y + dy, rectangle.X + dx] = 0;
+            }
+        }
+
+        return rectangle;
+    }
+}

src/LargeGridPathfinding/InputHelper.cs

@@ -0,0 +1,31 @@
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Input;
+
+using MonoGame.Extended.Input;
+
+namespace LargeGridPathfinding;
+
+internal static class InputHelper
+{
+    public static Vector2 GetMovementDirection(this KeyboardStateExtended keyboardState)
+    {
+        Vector2 movementDirection = Vector2.Zero;
+        if (keyboardState.IsKeyDown(Keys.S))
+        {
+            movementDirection += Vector2.UnitY;
+        }
+        if (keyboardState.IsKeyDown(Keys.W))
+        {
+            movementDirection -= Vector2.UnitY;
+        }
+        if (keyboardState.IsKeyDown(Keys.A))
+        {
+            movementDirection -= Vector2.UnitX;
+        }
+        if (keyboardState.IsKeyDown(Keys.D))
+        {
+            movementDirection += Vector2.UnitX;
+        }
+        return movementDirection;
+    }
+}

src/LargeGridPathfinding/LargeGridPathfinding.csproj

@@ -0,0 +1,35 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>WinExe</OutputType>
+    <TargetFramework>net8.0</TargetFramework>
+    <RollForward>Major</RollForward>
+    <PublishReadyToRun>false</PublishReadyToRun>
+    <TieredCompilation>false</TieredCompilation>
+  </PropertyGroup>
+  <PropertyGroup>
+    <ApplicationManifest>app.manifest</ApplicationManifest>
+    <ApplicationIcon>Icon.ico</ApplicationIcon>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+  <ItemGroup>
+    <None Remove="Icon.ico" />
+    <None Remove="Icon.bmp" />
+  </ItemGroup>
+  <ItemGroup>
+    <EmbeddedResource Include="Icon.ico">
+      <LogicalName>Icon.ico</LogicalName>
+    </EmbeddedResource>
+    <EmbeddedResource Include="Icon.bmp">
+      <LogicalName>Icon.bmp</LogicalName>
+    </EmbeddedResource>
+  </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="MonoGame.Extended" Version="4.0.4" />
+    <PackageReference Include="MonoGame.Framework.DesktopGL" Version="3.8.2.1105" />
+    <PackageReference Include="MonoGame.Content.Builder.Task" Version="3.8.2.1105" />
+  </ItemGroup>
+  <Target Name="RestoreDotnetTools" BeforeTargets="Restore">
+    <Message Text="Restoring dotnet tools" Importance="High" />
+    <Exec Command="dotnet tool restore" />
+  </Target>
+</Project>

src/LargeGridPathfinding/LargeGridPathfindingGame.cs

@@ -0,0 +1,652 @@
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+using Microsoft.Xna.Framework.Input;
+
+using MonoGame.Extended;
+using MonoGame.Extended.Input;
+
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+
+namespace LargeGridPathfinding;
+
+public class LargeGridPathfindingGame : Game
+{
+    private readonly ConcurrentDictionary<Vector2, Color> temporaryIndicators = [];
+    private readonly ProgressTracker progressTracker = new ProgressTracker();
+    private readonly List<Agent> agents = [];
+    private SpriteBatch spriteBatch = null!;
+    private SpriteBatch uiSpriteBatch = null!;
+    private SpriteFont uiFont = null!;
+    private OrthographicCamera camera = null!;
+    private GridFiller gridFiller = null!;
+    private Pathfinder pathfinder = null!;
+    private bool gridChanged;
+    private bool inputBlocked = true;
+    private bool showZones = true;
+    private bool showGrid = false;
+    private bool showPaths = false;
+    private Vector2? previousMousePosition;
+
+    public LargeGridPathfindingGame()
+    {
+        _ = new GraphicsDeviceManager(this)
+        {
+            PreferredBackBufferWidth = 1920,
+            PreferredBackBufferHeight = 1080
+        };
+
+        Content.RootDirectory = "Content";
+        IsMouseVisible = true;
+
+        Window.Title = "Large Grid Pathfinding";
+        Window.AllowUserResizing = true;
+    }
+
+    protected override void Initialize()
+    {
+        camera = new OrthographicCamera(GraphicsDevice)
+        {
+            MinimumZoom = 0.1f,
+            MaximumZoom = 2,
+            Zoom = 0.5f,
+        };
+
+        StartInitializationTask();
+
+        base.Initialize();
+    }
+
+    protected override void LoadContent()
+    {
+        spriteBatch = new SpriteBatch(GraphicsDevice);
+        uiSpriteBatch = new SpriteBatch(GraphicsDevice);
+        uiFont = Content.Load<SpriteFont>("ManoloMono");
+    }
+
+    protected override void Update(GameTime gameTime)
+    {
+        if (!IsActive)
+        {
+            return;
+        }
+
+        if (pathfinder is not null)
+        {
+            // Update agent positions
+            foreach (Agent agent in agents)
+            {
+                if (agent.Path is null || agent.Path.Count < 2)
+                {
+                    continue;
+                }
+
+                if (Vector2.Distance(agent.Position, agent.NextPosition) < 0.1)
+                {
+                    if (agent.NextPosition == agent.Path[^1])
+                    {
+                        agent.Path = null;
+                        agent.Destination = null;
+                    }
+                    else
+                    {
+                        agent.NextPosition = agent.Path[agent.Path.LastIndexOf(agent.NextPosition) + 1];
+                    }
+                }
+                else
+                {
+                    float distance = Vector2.Distance(agent.Position, agent.NextPosition);
+                    float lerpFactor = Math.Min(10 / distance * gameTime.GetElapsedSeconds(), 1);
+
+                    Vector2 nextPosition = Vector2.Lerp(agent.Position, agent.NextPosition, lerpFactor);
+
+                    int newX = (int)Math.Round(nextPosition.X);
+                    int newY = (int)Math.Round(nextPosition.Y);
+
+                    int[,] grid = gridFiller.Grid;
+
+                    if (grid[newY, newX] < 0)
+                    {
+                        agent.Path = null;
+                        continue;
+                    }
+
+                    agent.Position = nextPosition;
+                }
+            }
+        }
+
+        MouseExtended.Update();
+        KeyboardExtended.Update();
+
+        MouseStateExtended mouseState = MouseExtended.GetState();
+        KeyboardStateExtended keyboardState = KeyboardExtended.GetState();
+
+        float movementSpeed = (float)Math.Pow(200, 2 - camera.Zoom);
+
+        movementSpeed = Math.Clamp(movementSpeed, 1000, 20000);
+
+        camera.Move(keyboardState.GetMovementDirection() * movementSpeed * gameTime.GetElapsedSeconds());
+
+        if (mouseState.DeltaScrollWheelValue < 0)
+        {
+            camera.ZoomIn(0.1f);
+        }
+        else if (mouseState.DeltaScrollWheelValue > 0)
+        {
+            camera.ZoomOut(0.1f);
+        }
+
+        if (inputBlocked)
+        {
+            return;
+        }
+
+        // Toggle debug options
+
+        if (keyboardState.WasKeyPressed(Keys.Z))
+        {
+            showZones = !showZones;
+        }
+
+        if (keyboardState.WasKeyPressed(Keys.G))
+        {
+            showGrid = !showGrid;
+        }
+
+        if (keyboardState.WasKeyPressed(Keys.P))
+        {
+            showPaths = !showPaths;
+        }
+
+        if (keyboardState.WasKeyPressed(Keys.F))
+        {
+            Debug.WriteLine("Filling grid...");
+
+            _ = progressTracker.AddProgress("Filling grid", out IProgress<float> fillingGridProgressReporter);
+            _ = progressTracker.AddProgress("Calculating candidates", out IProgress<float> calculatingCandidatesProgressReporter);
+            _ = progressTracker.AddProgress("Placing zones", out IProgress<float> placingCandidatesProgressReporter);
+
+            bool showZonesBefore = showZones;
+            bool showGridBefore = showGrid;
+            bool showPathsBefore = showPaths;
+            showZones = true;
+            showGrid = false;
+            showPaths = false;
+            inputBlocked = true;
+
+            _ = Task.Run(() =>
+            {
+                gridFiller.FillGrid(fillAll: true, totalProgress: fillingGridProgressReporter, calculatingCandidatesProgress: calculatingCandidatesProgressReporter, placingCandidatesProgress: placingCandidatesProgressReporter);
+                gridChanged = true;
+                inputBlocked = false;
+                showZones = showZonesBefore;
+                showGrid = showGridBefore;
+                showPaths = showPathsBefore;
+            });
+        }
+
+        // Place or remove obstacles via mouse input
+
+        if (mouseState.IsButtonDown(MouseButton.Left))
+        {
+            Vector2 mousePosition = camera.ScreenToWorld(mouseState.Position.ToVector2());
+            Vector2 gridPosition = new Vector2((int)mousePosition.X / 10, (int)mousePosition.Y / 10);
+
+            if (gridPosition.X < 0 || gridPosition.X >= gridFiller.Width || gridPosition.Y < 0 || gridPosition.Y >= gridFiller.Height || gridFiller.Grid[(int)gridPosition.Y, (int)gridPosition.X] < 0 || temporaryIndicators.ContainsKey(gridPosition))
+            {
+                return;
+            }
+
+            Vector2? previousGridPosition = null;
+            if (previousMousePosition is not null)
+            {
+                previousGridPosition = new Vector2((int)previousMousePosition.Value.X / 10, (int)previousMousePosition.Value.Y / 10);
+            }
+
+            // Place temporary indicators to show the obstacle is scheduled for placement
+            temporaryIndicators[gridPosition] = Color.Red;
+
+            previousMousePosition = mousePosition;
+
+            _ = Task.Run(() =>
+            {
+                if (previousGridPosition is not null)
+                {
+                    List<Vector2> interpolatedPositions = [];
+
+                    // Interpolate between previous and current mouse position to place obstacles in a straight line to prevent gaps
+                    float distance = Vector2.Distance(previousGridPosition.Value, gridPosition);
+                    float lerpSteps = distance * 10;
+
+                    for (float t = 0; t <= 1; t += 1 / lerpSteps)
+                    {
+                        Vector2 interpolatedPosition = Vector2.Lerp(previousGridPosition.Value, gridPosition, t);
+                        interpolatedPosition.Round();
+                        interpolatedPositions.Add(interpolatedPosition);
+                        temporaryIndicators[interpolatedPosition] = Color.Red;
+                    }
+
+                    foreach (Vector2 interpolatedPosition in interpolatedPositions.Distinct())
+                    {
+                        gridFiller.PlaceObstacle(new Rectangle((int)interpolatedPosition.X, (int)interpolatedPosition.Y, 1, 1));
+                        _ = temporaryIndicators.TryRemove(interpolatedPosition, out _);
+                    }
+                }
+
+                gridFiller.PlaceObstacle(new Rectangle((int)gridPosition.X, (int)gridPosition.Y, 1, 1));
+                gridChanged = true;
+                _ = temporaryIndicators.TryRemove(gridPosition, out _);
+            });
+        }
+        else if (mouseState.IsButtonDown(MouseButton.Right))
+        {
+            Vector2 mousePosition = camera.ScreenToWorld(mouseState.Position.ToVector2());
+            Vector2 gridPosition = new Vector2((int)mousePosition.X / 10, (int)mousePosition.Y / 10);
+
+            if (gridPosition.X < 0 || gridPosition.X >= gridFiller.Width || gridPosition.Y < 0 || gridPosition.Y >= gridFiller.Height || gridFiller.Grid[(int)gridPosition.Y, (int)gridPosition.X] > 0 || temporaryIndicators.ContainsKey(gridPosition))
+            {
+                return;
+            }
+
+            Vector2? previousGridPosition = null;
+            if (previousMousePosition is not null)
+            {
+                previousGridPosition = new Vector2((int)previousMousePosition.Value.X / 10, (int)previousMousePosition.Value.Y / 10);
+            }
+
+            // Place temporary indicators to show the obstacle is scheduled for removal
+            temporaryIndicators[gridPosition] = Color.Yellow;
+
+            previousMousePosition = mousePosition;
+
+            _ = Task.Run(() =>
+            {
+                if (previousGridPosition is not null)
+                {
+                    List<Vector2> interpolatedPositions = [];
+
+                    // Interpolate between previous and current mouse position to place obstacles in a straight line to prevent gaps
+
+                    float distance = Vector2.Distance(previousGridPosition.Value, gridPosition);
+                    float lerpSteps = distance * 10;
+
+                    for (float t = 0; t <= 1; t += 1 / lerpSteps)
+                    {
+                        Vector2 interpolatedPosition = Vector2.Lerp(previousGridPosition.Value, gridPosition, t);
+                        interpolatedPosition.Round();
+                        interpolatedPositions.Add(interpolatedPosition);
+                        temporaryIndicators[interpolatedPosition] = Color.Yellow;
+                    }
+
+                    foreach (Vector2 interpolatedPosition in interpolatedPositions.Distinct())
+                    {
+                        gridFiller.RemoveObstacle(new Rectangle((int)interpolatedPosition.X, (int)interpolatedPosition.Y, 1, 1));
+                        _ = temporaryIndicators.TryRemove(interpolatedPosition, out _);
+                    }
+                }
+
+                gridFiller.RemoveObstacle(new Rectangle((int)gridPosition.X, (int)gridPosition.Y, 1, 1));
+                gridChanged = true;
+                _ = temporaryIndicators.TryRemove(gridPosition, out _);
+            });
+        }
+        else
+        {
+            previousMousePosition = null;
+        }
+
+        base.Update(gameTime);
+    }
+
+    protected override void Draw(GameTime gameTime)
+    {
+        if (gridFiller is null)
+        {
+            return;
+        }
+
+        GraphicsDevice.Clear(Color.CornflowerBlue);
+
+        Matrix transformMatrix = camera.GetViewMatrix();
+
+        int yStart = Math.Max(0, (int)(camera.BoundingRectangle.Top / 10) - 2);
+        int xStart = Math.Max(0, (int)(camera.BoundingRectangle.Left / 10) - 2);
+        int yEnd = Math.Min(gridFiller.Height, (int)(camera.BoundingRectangle.Bottom / 10) + 2);
+        int xEnd = Math.Min(gridFiller.Width, (int)(camera.BoundingRectangle.Right / 10) + 2);
+
+        int[,] grid = gridFiller.Grid;
+        Rectangle cellRect = new Rectangle(0, 0, 10, 10);
+
+        Color[] colorLookup = [
+        Color.Blue, Color.Cyan, Color.Magenta, Color.Yellow, Color.Orange,
+        Color.DarkMagenta, Color.DarkCyan, Color.Tan, Color.RosyBrown,
+        Color.DarkKhaki, Color.DarkSalmon, Color.DarkSlateGray,
+        Color.DarkTurquoise, Color.DarkGoldenrod, Color.Aqua, Color.Aquamarine,
+        Color.Bisque, Color.DarkSlateBlue, Color.BlueViolet, Color.Brown,
+        Color.BurlyWood, Color.CadetBlue, Color.Chartreuse, Color.Chocolate,
+        Color.Coral, Color.CornflowerBlue, Color.Crimson, Color.DarkBlue
+    ];
+
+        // Draw grid cells
+        spriteBatch.Begin(SpriteSortMode.Deferred, samplerState: SamplerState.PointClamp, transformMatrix: transformMatrix);
+
+        spriteBatch.FillRectangle(new Rectangle(0, 0, gridFiller.Width * 10, gridFiller.Height * 10), Color.White, layerDepth: 0.4f);
+
+        if (showZones)
+        {
+            Dictionary<int, Rectangle> rectangles = new Dictionary<int, Rectangle>(gridFiller.PlacedRectangles);
+
+            foreach ((int label, Rectangle rectangle) in rectangles)
+            {
+                Color color = colorLookup[label % 28];
+
+                spriteBatch.FillRectangle(new Rectangle(rectangle.X * 10, rectangle.Y * 10, rectangle.Width * 10, rectangle.Height * 10), color, layerDepth: 0.2f);
+            }
+        }
+
+        for (int y = yStart; y < yEnd; y++)
+        {
+            for (int x = xStart; x < xEnd; x++)
+            {
+                cellRect.X = x * 10;
+                cellRect.Y = y * 10;
+
+                int cellValue = grid[y, x];
+
+                if (cellValue < 0)
+                {
+                    spriteBatch.FillRectangle(cellRect, Color.Red, layerDepth: 0.3f);
+                }
+
+                if (temporaryIndicators.TryGetValue(new Vector2(x, y), out Color indicatorColor))
+                {
+                    spriteBatch.DrawCircle(cellRect.Center.ToVector2(), 5, 10, indicatorColor, 2f, layerDepth: 0.2f);
+                }
+
+                if (showGrid)
+                {
+                    spriteBatch.DrawRectangle(cellRect, Color.Black, layerDepth: 0.2f);
+                }
+            }
+        }
+        spriteBatch.End();
+
+        // Draw paths in a separate batch if needed
+        if (showPaths)
+        {
+            spriteBatch.Begin(SpriteSortMode.Deferred, samplerState: SamplerState.PointClamp, transformMatrix: transformMatrix);
+            foreach (List<Vector2>? path in agents.Select(a => a.Path))
+            {
+                if (path is null)
+                {
+                    continue;
+                }
+
+                for (int i = 0; i < path.Count - 1; i++)
+                {
+                    Vector2 start = (path[i] * 10) + new Vector2(5, 5);
+                    Vector2 end = (path[i + 1] * 10) + new Vector2(5, 5);
+
+                    if ((start.X < camera.BoundingRectangle.Left - 10 && end.X < camera.BoundingRectangle.Left - 10) ||
+                        (start.X > camera.BoundingRectangle.Right + 10 && end.X > camera.BoundingRectangle.Right + 10) ||
+                        (start.Y < camera.BoundingRectangle.Top - 10 && end.Y < camera.BoundingRectangle.Top - 10) ||
+                        (start.Y > camera.BoundingRectangle.Bottom + 10 && end.Y > camera.BoundingRectangle.Bottom + 10))
+                    {
+                        continue;
+                    }
+
+                    spriteBatch.DrawLine(start, end, Color.Black, 2f, layerDepth: 0.1f);
+                    spriteBatch.DrawCircle(start, 5, 10, i == 0 ? Color.Green : Color.Black, 2f, layerDepth: 0.1f);
+                    spriteBatch.DrawCircle(end, 5, 10, i == path.Count - 2 ? Color.Red : Color.Black, 2f, layerDepth: 0.1f);
+                }
+            }
+            spriteBatch.End();
+        }
+
+        // Draw agents
+        spriteBatch.Begin(SpriteSortMode.Deferred, samplerState: SamplerState.PointClamp, transformMatrix: transformMatrix);
+
+        foreach (Vector2 currentPosition in agents.Select(a => a.Position))
+        {
+            if (currentPosition.X < xStart || currentPosition.X > xEnd || currentPosition.Y < yStart || currentPosition.Y > yEnd)
+            {
+                continue;
+            }
+
+            spriteBatch.DrawCircle((currentPosition + new Vector2(0.5f, 0.5f)) * 10, 5, 10, Color.Blue, 2f, layerDepth: 0.1f);
+        }
+
+        spriteBatch.End();
+
+        // Draw UI elements
+        uiSpriteBatch.Begin(SpriteSortMode.Deferred, samplerState: SamplerState.PointClamp);
+
+        uiSpriteBatch.DrawString(uiFont, $"FPS: {1 / gameTime.GetElapsedSeconds():0}", new Vector2(10, 10), Color.Black);
+        uiSpriteBatch.DrawString(uiFont, $"Grid: {gridFiller.Width}x{gridFiller.Height}", new Vector2(10, 30), Color.Black);
+        uiSpriteBatch.DrawString(uiFont, $"Zones: {gridFiller.PlacedRectangles.Count}", new Vector2(10, 50), Color.Black);
+        uiSpriteBatch.DrawString(uiFont, $"Agents: {agents.Count}", new Vector2(10, 70), Color.Black);
+
+        IReadOnlyList<ProgressTracker.ProgressData> progresses = progressTracker.GetProgresses();
+
+        for (int i = 0; i < progresses.Count; i++)
+        {
+            ProgressTracker.ProgressData progressData = progresses[i];
+
+            string progress = progressData.Indeterminate ? "..." : progressData.Progress.ToString("P0");
+
+            uiSpriteBatch.DrawString(uiFont, $"{progressData.Name}: {progress}", new Vector2(10, 90 + (i * 20)), Color.Black);
+        }
+
+        uiSpriteBatch.End();
+
+        base.Draw(gameTime);
+    }
+
+    private void StartInitializationTask()
+    {
+        _ = Task.Run(() =>
+        {
+            // Configuration options
+            int width = 1000;
+            int height = 1000;
+            int agentCount = 10000;
+
+            bool pathRandomization = true; // Randomize path costs to prevent agents from following the same path
+            bool penalizeStretchedRectangles = true; // (EXPERIMENTAL) Penalize paths that go through stretched rectangles to prevent too many agents in a small area
+
+            for (int i = 0; i < agentCount; i++)
+            {
+                int x = Random.Shared.Next(0, width - 1);
+                int y = Random.Shared.Next(0, height - 1);
+
+                agents.Add(new(new Vector2(x, y)));
+            }
+
+            List<Rectangle> obstacles = [];
+
+            Debug.WriteLine("Generating random obstacles...");
+
+            // Generate room/building like obstacles with walls and doors
+
+            for (int i = 0; i < (width + height) / 2; i++)
+            {
+                int x = Random.Shared.Next(0, width - 1);
+                int y = Random.Shared.Next(0, height - 1);
+                int w = Random.Shared.Next(5, (width + height) / 100);
+                int h = Random.Shared.Next(5, (width + height) / 100);
+
+                Rectangle wall1 = new(x, y, w, 1);            // Top wall
+                Rectangle wall2 = new(x, y, 1, h);            // Left wall
+                Rectangle wall3 = new(x + w - 1, y, 1, h); // Right wall
+                Rectangle wall4 = new(x, y + h - 1, w, 1); // Bottom wall
+
+                int doorSide = Random.Shared.Next(4); // Choose a random side for the door
+
+                if (doorSide == 0) // Bottom side
+                {
+                    obstacles.Add(wall1);
+                    obstacles.Add(wall2);
+                    obstacles.Add(wall3);
+
+                    int doorX = x + Random.Shared.Next(1, w - 2);
+                    Rectangle doorWall1 = new(x, y + h - 1, doorX - x, 1);
+                    Rectangle doorWall2 = new(doorX + 2, y + h - 1, x + w - (doorX + 2), 1);
+
+                    obstacles.Add(doorWall1);
+                    obstacles.Add(doorWall2);
+                }
+                else if (doorSide == 1) // Top side
+                {
+                    obstacles.Add(wall2);
+                    obstacles.Add(wall3);
+                    obstacles.Add(wall4);
+
+                    int doorX = x + Random.Shared.Next(1, w - 2);
+                    Rectangle doorWall1 = new(x, y, doorX - x, 1);
+                    Rectangle doorWall2 = new(doorX + 2, y, x + w - (doorX + 2), 1);
+
+                    obstacles.Add(doorWall1);
+                    obstacles.Add(doorWall2);
+                }
+                else if (doorSide == 2) // Left side
+                {
+                    obstacles.Add(wall1);
+                    obstacles.Add(wall3);
+                    obstacles.Add(wall4);
+
+                    int doorY = y + Random.Shared.Next(1, h - 2);
+                    Rectangle doorWall1 = new(x, y, 1, doorY - y);
+                    Rectangle doorWall2 = new(x, doorY + 2, 1, y + h - (doorY + 2));
+
+                    obstacles.Add(doorWall1);
+                    obstacles.Add(doorWall2);
+                }
+                else if (doorSide == 3) // Right side
+                {
+                    obstacles.Add(wall1);
+                    obstacles.Add(wall2);
+                    obstacles.Add(wall4);
+
+                    int doorY = y + Random.Shared.Next(1, h - 2);
+                    Rectangle doorWall1 = new(x + w - 1, y, 1, doorY - y);
+                    Rectangle doorWall2 = new(x + w - 1, doorY + 2, 1, y + h - (doorY + 2));
+
+                    obstacles.Add(doorWall1);
+                    obstacles.Add(doorWall2);
+                }
+            }
+
+            Debug.WriteLine("Initializing grid...");
+
+            ProgressTracker.ProgressData progressData = progressTracker.AddProgress("Initializing grid", true, out _);
+            gridFiller = new GridFiller(width, height, obstacles);
+            progressTracker.RemoveProgress(progressData);
+
+            Debug.WriteLine("Filling grid...");
+
+            _ = progressTracker.AddProgress("Filling grid", out IProgress<float> fillingGridProgressReporter);
+            _ = progressTracker.AddProgress("Calculating candidates", out IProgress<float> calculatingCandidatesProgressReporter);
+            _ = progressTracker.AddProgress("Placing zones", out IProgress<float> placingCandidatesProgressReporter);
+
+            gridFiller.FillGrid(totalProgress: fillingGridProgressReporter, calculatingCandidatesProgress: calculatingCandidatesProgressReporter, placingCandidatesProgress: placingCandidatesProgressReporter);
+
+            pathfinder = new Pathfinder(gridFiller.PlacedRectangles, pathRandomization, penalizeStretchedRectangles);
+            gridChanged = true;
+            inputBlocked = false;
+            showZones = false;
+            showPaths = false;
+
+            StartUpdatePathTask();
+        });
+    }
+
+    // Handles pathfinding calculations in a separate task
+    private void StartUpdatePathTask()
+    {
+        _ = Task.Factory.StartNew(async () =>
+        {
+            while (true)
+            {
+                try
+                {
+                    if (gridChanged)
+                    {
+                        gridChanged = false;
+                        ProgressTracker.ProgressData progressDataBuildGraph = progressTracker.AddProgress("Rebuilding graph", true, out _);
+                        pathfinder.RebuildGraph();
+                        progressTracker.RemoveProgress(progressDataBuildGraph);
+                    }
+
+                    Agent[] agentsRequirePath = agents.Where(a => a.Path is null).ToArray();
+
+                    if (agentsRequirePath.Length != 0)
+                    {
+                        ProgressTracker.ProgressData progressDataPaths = progressTracker.AddProgress($"Calculating {agentsRequirePath.Length} paths", out IProgress<float> progress);
+
+                        int pathsCalculated = 0;
+                        int reportInterval = Math.Max(1, agentsRequirePath.Length / 10);
+
+                        // Calculate paths for agents that require a new path
+                        _ = Parallel.For(0, agentsRequirePath.Length, i =>
+                        {
+                            Agent agent = agentsRequirePath[i];
+
+                            agent.Path = CalculatePath(agent.GridPosition, agent.Destination);
+                            agent.Path ??= CalculatePath();
+                            agent.Position = agent.Path?[0] ?? agent.Position;
+                            agent.NextPosition = agent.Path?[1] ?? agent.Position;
+                            agent.Destination = agent.Path?.LastOrDefault().ToPoint();
+
+                            int localPathsCalculated = Interlocked.Increment(ref pathsCalculated);
+
+                            if (localPathsCalculated % reportInterval == 0)
+                            {
+                                progress.Report((float)localPathsCalculated / agentsRequirePath.Length);
+                            }
+                        });
+
+                        progressTracker.RemoveProgress(progressDataPaths);
+                    }
+
+                    await Task.Delay(100);
+                }
+                catch (Exception ex)
+                {
+                    Debug.WriteLine(ex);
+                }
+            }
+        }, TaskCreationOptions.LongRunning);
+    }
+
+    private List<Vector2>? CalculatePath(Point? start = null, Point? goal = null)
+    {
+        int width = gridFiller.Width;
+        int height = gridFiller.Height;
+        int startX = Random.Shared.Next(0, width - 1);
+        int startY = Random.Shared.Next(0, height - 1);
+        int goalX = Random.Shared.Next(0, width - 1);
+        int goalY = Random.Shared.Next(0, height - 1);
+
+        start ??= new Point(startX, startY);
+        goal ??= new Point(goalX, goalY);
+
+        int[,] grid = gridFiller.Grid;
+
+        List<Vector2>? path = pathfinder.FindPath(ref grid[start.Value.Y, start.Value.X], ref grid[goal.Value.Y, goal.Value.X]);
+
+        if (path is not null)
+        {
+            // Add start and goal positions to the path because the pathfinder only returns transitions between rectangles
+            path.Insert(0, start.Value.ToVector2());
+            path.Add(goal.Value.ToVector2());
+        }
+
+        return path;
+    }
+}

src/LargeGridPathfinding/Pathfinder.cs

@@ -0,0 +1,231 @@
+using Microsoft.Xna.Framework;
+
+using System;
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Diagnostics;
+using System.Linq;
+
+namespace LargeGridPathfinding;
+
+internal class Pathfinder
+{
+    private readonly ConcurrentDictionary<int, Rectangle> rectanglesSource;
+    private readonly bool pathRandomization;
+    private readonly bool penalizeStretchedRectangles;
+    private Dictionary<int, Rectangle> rectangleMap;
+    private Dictionary<int, List<int>> adjacencyList;
+
+    public Pathfinder(ConcurrentDictionary<int, Rectangle> rectangles, bool pathRandomization = false, bool penalizeStretchedRectangles = false)
+    {
+        rectanglesSource = rectangles;
+        this.pathRandomization = pathRandomization;
+        this.penalizeStretchedRectangles = penalizeStretchedRectangles;
+        rectangleMap = new Dictionary<int, Rectangle>(rectangles);
+        adjacencyList = BuildGraph();
+    }
+
+    public List<Vector2>? FindPath(ref int start, ref int goal)
+    {
+        PriorityQueue<(int node, List<int> path, int cost), int> queue = new PriorityQueue<(int node, List<int> path, int cost), int>();
+        HashSet<int> visited = [];
+        queue.Enqueue((start, new List<int> { start }, 0), 0);
+
+        if (!rectangleMap.ContainsKey(start) || !rectangleMap.ContainsKey(goal))
+        {
+            Debug.WriteLine($"{(rectangleMap.ContainsKey(start) ? "Goal" : "Start")} rectangle not found.");
+            return null;
+        }
+
+        while (queue.Count > 0)
+        {
+            (int node, List<int> path, int cost) = queue.Dequeue();
+
+            if (node == goal)
+            {
+                // Convert rectangle path to coordinate transitions
+                List<Vector2> coordinatePath = [];
+
+                for (int i = 0; i < path.Count - 1; i++)
+                {
+                    (Vector2 entry, Vector2 exit) = GetTransitionPoints(path[i], path[i + 1], i + 2 < path.Count ? path[i + 2] : null);
+                    coordinatePath.Add(entry);
+                    coordinatePath.Add(exit);
+                }
+
+                return coordinatePath;
+            }
+
+            if (visited.Contains(node))
+            {
+                continue;
+            }
+
+            _ = visited.Add(node);
+
+            foreach (int neighbor in adjacencyList.TryGetValue(node, out List<int>? neighbors) ? neighbors : [])
+            {
+                if (!visited.Contains(neighbor))
+                {
+                    List<int> newPath = new List<int>(path) { neighbor };
+
+                    int newCost = cost + 1;
+
+                    if (penalizeStretchedRectangles)
+                    {
+                        newCost += Math.Max(rectangleMap[neighbor].Width, rectangleMap[neighbor].Height) / Math.Min(rectangleMap[neighbor].Width, rectangleMap[neighbor].Height);
+                    }
+
+                    if (pathRandomization)
+                    {
+                        newCost += Random.Shared.Next(-1, 2);
+                    }
+
+                    queue.Enqueue((neighbor, newPath, newCost), newCost);
+                }
+            }
+        }
+
+        return null;
+    }
+
+    public void RebuildGraph()
+    {
+        rectangleMap = new Dictionary<int, Rectangle>(rectanglesSource);
+        adjacencyList.Clear();
+        adjacencyList = BuildGraph();
+    }
+
+    private static bool AreRectanglesAdjacent(Rectangle r1, Rectangle r2)
+    {
+        bool adjacentHorizontally = (r1.X + r1.Width == r2.X || r2.X + r2.Width == r1.X) && r1.Y < r2.Y + r2.Height && r1.Y + r1.Height > r2.Y;
+        bool adjacentVertically = (r1.Y + r1.Height == r2.Y || r2.Y + r2.Height == r1.Y) && r1.X < r2.X + r2.Width && r1.X + r1.Width > r2.X;
+        return adjacentHorizontally || adjacentVertically;
+    }
+
+    private Vector2 GetRectangleClosestEdge(Rectangle rect, Vector2 point)
+    {
+        if (pathRandomization)
+        {
+            float randomX = Random.Shared.Next(rect.Left, rect.Right);
+            float randomY = Random.Shared.Next(rect.Top, rect.Bottom);
+            return new Vector2(randomX, randomY);
+        }
+
+        // Clamp the point to the closest edge of the rectangle
+        float closestX = Math.Clamp(point.X, rect.Left, rect.Right - 1);
+        float closestY = Math.Clamp(point.Y, rect.Top, rect.Bottom - 1);
+
+        // If point is inside the rectangle, push it to the nearest edge
+        if (point.X >= rect.Left && point.X < rect.Right &&
+            point.Y >= rect.Top && point.Y < rect.Bottom)
+        {
+            float leftDistance = Math.Abs(point.X - rect.Left);
+            float rightDistance = Math.Abs(point.X - (rect.Right - 1));
+            float topDistance = Math.Abs(point.Y - rect.Top);
+            float bottomDistance = Math.Abs(point.Y - (rect.Bottom - 1));
+
+            float minDistance = Math.Min(Math.Min(leftDistance, rightDistance), Math.Min(topDistance, bottomDistance));
+
+            if (minDistance == leftDistance)
+            {
+                closestX = rect.Left;
+            }
+            else if (minDistance == rightDistance)
+            {
+                closestX = rect.Right - 1;
+            }
+            else if (minDistance == topDistance)
+            {
+                closestY = rect.Top;
+            }
+            else if (minDistance == bottomDistance)
+            {
+                closestY = rect.Bottom - 1;
+            }
+        }
+
+        return new Vector2(closestX, closestY);
+    }
+
+    // Build a graph where each rectangle is a node and each edge represents an adjacency
+    private Dictionary<int, List<int>> BuildGraph()
+    {
+        Dictionary<int, List<int>> graph = [];
+
+        foreach (KeyValuePair<int, Rectangle> rect1 in rectangleMap)
+        {
+            if (!graph.ContainsKey(rect1.Key))
+            {
+                graph[rect1.Key] = [];
+            }
+
+            foreach (KeyValuePair<int, Rectangle> rect2 in rectangleMap)
+            {
+                if (rect1.Key != rect2.Key && AreRectanglesAdjacent(rect1.Value, rect2.Value))
+                {
+                    graph[rect1.Key].Add(rect2.Key);
+                }
+            }
+        }
+
+        return graph;
+    }
+
+    // Find the transition points between two rectangles
+    private (Vector2 entry, Vector2 exit) GetTransitionPoints(int from, int to, int? next = null)
+    {
+        Rectangle r1 = rectangleMap[from];
+        Rectangle r2 = rectangleMap[to];
+
+        // Find all possible valid transition points
+        List<(Vector2 entry, Vector2 exit)> possibleTransitions = [];
+
+        if (r1.Right == r2.Left)
+        {
+            for (int y = Math.Max(r1.Top, r2.Top); y < Math.Min(r1.Bottom, r2.Bottom); y++)
+            {
+                possibleTransitions.Add((new Vector2(r1.Right - 1, y), new Vector2(r2.Left, y)));
+            }
+        }
+        else if (r2.Right == r1.Left)
+        {
+            for (int y = Math.Max(r1.Top, r2.Top); y < Math.Min(r1.Bottom, r2.Bottom); y++)
+            {
+                possibleTransitions.Add((new Vector2(r1.Left, y), new Vector2(r2.Right - 1, y)));
+            }
+        }
+        else if (r1.Bottom == r2.Top)
+        {
+            for (int x = Math.Max(r1.Left, r2.Left); x < Math.Min(r1.Right, r2.Right); x++)
+            {
+                possibleTransitions.Add((new Vector2(x, r1.Bottom - 1), new Vector2(x, r2.Top)));
+            }
+        }
+        else if (r2.Bottom == r1.Top)
+        {
+            for (int x = Math.Max(r1.Left, r2.Left); x < Math.Min(r1.Right, r2.Right); x++)
+            {
+                possibleTransitions.Add((new Vector2(x, r1.Top), new Vector2(x, r2.Bottom - 1)));
+            }
+        }
+
+        if (possibleTransitions.Count == 0)
+        {
+            return (new Vector2(-1, -1), new Vector2(-1, -1));
+        }
+
+        // If there's a next rectangle, optimize the transition to minimize the distance
+        if (next is not null && rectangleMap.TryGetValue(next.Value, out Rectangle r3))
+        {
+            (Vector2 entry, Vector2 exit) bestTransition = possibleTransitions
+                .OrderBy(t => Vector2.DistanceSquared(t.exit, GetRectangleClosestEdge(r3, t.exit)))
+                .First();
+
+            return bestTransition;
+        }
+
+        // Default: Pick the middle transition point
+        return possibleTransitions[possibleTransitions.Count / 2];
+    }
+}

src/LargeGridPathfinding/Program.cs

@@ -0,0 +1,2 @@
+using LargeGridPathfinding.LargeGridPathfindingGame game = new LargeGridPathfinding.LargeGridPathfindingGame();
+game.Run();

src/LargeGridPathfinding/ProgressTracker.cs

@@ -0,0 +1,79 @@
+using System;
+using System.Collections.Generic;
+
+namespace LargeGridPathfinding;
+
+internal class ProgressTracker
+{
+    private readonly List<ProgressData> progresses = [];
+
+    public ProgressData AddProgress(string name, out IProgress<float> progress)
+    {
+        return AddProgress(name, false, false, out progress);
+    }
+
+    public ProgressData AddProgress(string name, bool indeterminate, out IProgress<float> progress)
+    {
+        return AddProgress(name, indeterminate, false, out progress);
+    }
+
+    public ProgressData AddProgress(string name, bool indeterminate, bool disableAutoRemove, out IProgress<float> progress)
+    {
+        CustomProgress<float> newProgress = new CustomProgress<float>();
+        ProgressData progressData = new ProgressData(name, indeterminate, disableAutoRemove);
+
+        newProgress.ProgressChanged += (_, progress) => Progress_ProgressChanged(progressData, progress);
+
+        lock (progresses)
+        {
+            progresses.Add(progressData);
+        }
+
+        progress = newProgress;
+        return progressData;
+    }
+
+    public void RemoveProgress(ProgressData progressData)
+    {
+        lock (progresses)
+        {
+            if (!progressData.DoNotRemove)
+            {
+                _ = progresses.Remove(progressData);
+            }
+        }
+    }
+
+    public IReadOnlyList<ProgressData> GetProgresses()
+    {
+        return progresses;
+    }
+
+    private void Progress_ProgressChanged(ProgressData progressData, float progress)
+    {
+        progressData.Progress = progress;
+
+        if (progress >= 1)
+        {
+            RemoveProgress(progressData);
+        }
+    }
+
+    public class ProgressData(string name, bool indeterminate, bool doNotRemove)
+    {
+        public string Name { get; } = name;
+        public float Progress { get; set; } = 0;
+        public bool Indeterminate { get; } = indeterminate;
+        public bool DoNotRemove { get; } = doNotRemove;
+    }
+
+    public class CustomProgress<T>() : IProgress<T>
+    {
+        public EventHandler<T>? ProgressChanged { get; set; }
+
+        public void Report(T value)
+        {
+            ProgressChanged?.Invoke(this, value);
+        }
+    }
+}

src/LargeGridPathfinding/app.manifest

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="utf-8"?>
+<assembly manifestVersion="1.0" xmlns="urn:schemas-microsoft-com:asm.v1">
+  <assemblyIdentity version="1.0.0.0" name="PathFinding"/>
+  <trustInfo xmlns="urn:schemas-microsoft-com:asm.v2">
+    <security>
+      <requestedPrivileges xmlns="urn:schemas-microsoft-com:asm.v3">
+        <requestedExecutionLevel  level="asInvoker" uiAccess="false" />
+      </requestedPrivileges>
+    </security>
+  </trustInfo>
+
+  <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+    <application>
+      <!-- A list of the Windows versions that this application has been tested on and is
+           is designed to work with. Uncomment the appropriate elements and Windows will 
+           automatically selected the most compatible environment. -->
+
+      <!-- Windows Vista -->
+      <supportedOS Id="{e2011457-1546-43c5-a5fe-008deee3d3f0}" />
+
+      <!-- Windows 7 -->
+      <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}" />
+
+      <!-- Windows 8 -->
+      <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}" />
+
+      <!-- Windows 8.1 -->
+      <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}" />
+
+      <!-- Windows 10 -->
+      <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}" />
+
+    </application>
+  </compatibility>
+
+  <application xmlns="urn:schemas-microsoft-com:asm.v3">
+    <windowsSettings>
+      <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">true/pm</dpiAware>
+      <dpiAwareness xmlns="http://schemas.microsoft.com/SMI/2016/WindowsSettings">permonitorv2,permonitor</dpiAwareness>
+    </windowsSettings>
+  </application>
+
+</assembly>