Imported from BasarEkinci/memory-card-game (.claude/skills/gameplay/procedural-generation/SKILL.md). Install upstream with npx skills add BasarEkinci/memory-card-game --skill procedural-generation. Copyright stays with the author.

Procedural Generation Patterns

Patterns for generating content at runtime: terrain with noise, dungeons with BSP, caves with random walk, loot with weighted tables, and tile layouts with wave function collapse. All patterns support seed-based reproducibility.

Seed-Based Reproducibility

Every generation algorithm should accept a seed. Given the same seed, the output is identical. This enables shareable worlds, bug reproduction, and daily challenge modes.

Critical rule: Use System.Random (not UnityEngine.Random) for deterministic generation. UnityEngine.Random is a global singleton; any other code calling it between your generation steps will change the sequence.

public class SeededRandom
{
    private System.Random _rng;
    public int Seed { get; }

    public SeededRandom(int seed)
    {
        Seed = seed;
        _rng = new System.Random(seed);
    }

    public int Next(int min, int max) => _rng.Next(min, max);
    public float NextFloat() => (float)_rng.NextDouble();
    public float Range(float min, float max) => min + (max - min) * NextFloat();
    public bool Chance(float probability) => NextFloat() < probability;

    /// <summary>Shuffle a list in place using Fisher-Yates.</summary>
    public void Shuffle<T>(IList<T> list)
    {
        for (int i = list.Count - 1; i > 0; i--)
        {
            int j = _rng.Next(0, i + 1);
            (list[i], list[j]) = (list[j], list[i]);
        }
    }
}

For world generation, derive sub-seeds from the master seed so different systems (terrain, dungeons, loot) do not interfere:

int masterSeed = 12345;
var terrainRng = new SeededRandom(masterSeed);
var dungeonRng = new SeededRandom(masterSeed + 1);
var lootRng = new SeededRandom(masterSeed + 2);

Noise-Based Terrain Generation

Use Perlin noise to generate height maps for terrain, biome maps, moisture maps, and other continuous fields.

Basic Height Map

using UnityEngine;

public static class NoiseGenerator
{
    /// <summary>
    /// Generate a 2D noise map. Values range from 0 to 1.
    /// </summary>
    public static float[,] GenerateNoiseMap(
        int width, int height, int seed,
        float scale, int octaves, float persistence, float lacunarity,
        Vector2 offset)
    {
        var map = new float[width, height];

        // Use seed to generate random octave offsets
        var rng = new System.Random(seed);
        var octaveOffsets = new Vector2[octaves];
        for (int i = 0; i < octaves; i++)
        {
            float ox = rng.Next(-100000, 100000) + offset.x;
            float oy = rng.Next(-100000, 100000) + offset.y;
            octaveOffsets[i] = new Vector2(ox, oy);
        }

        if (scale <= 0f) scale = 0.001f;

        float maxNoise = float.MinValue;
        float minNoise = float.MaxValue;

        float halfW = width / 2f;
        float halfH = height / 2f;

        for (int y = 0; y < height; y++)
        {
            for (int x = 0; x < width; x++)
            {
                float amplitude = 1f;
                float frequency = 1f;
                float noiseHeight = 0f;

                for (int o = 0; o < octaves; o++)
                {
                    float sampleX = (x - halfW + octaveOffsets[o].x) / scale * frequency;
                    float sampleY = (y - halfH + octaveOffsets[o].y) / scale * frequency;

                    // Mathf.PerlinNoise returns 0-1; remap to -1 to 1
                    float perlin = Mathf.PerlinNoise(sampleX, sampleY) * 2f - 1f;
                    noiseHeight += perlin * amplitude;

                    amplitude *= persistence;  // Each octave contributes less
                    frequency *= lacunarity;    // Each octave has finer detail
                }

                map[x, y] = noiseHeight;

                if (noiseHeight > maxNoise) maxNoise = noiseHeight;
                if (noiseHeight < minNoise) minNoise = noiseHeight;
            }
        }

        // Normalize to 0-1
        for (int y = 0; y < height; y++)
            for (int x = 0; x < width; x++)
                map[x, y] = Mathf.InverseLerp(minNoise, maxNoise, map[x, y]);

        return map;
    }
}

Parameter guide:

Applying Noise to a Tilemap

using UnityEngine;
using UnityEngine.Tilemaps;

public class TerrainGenerator : MonoBehaviour
{
    [SerializeField] private Tilemap tilemap;
    [SerializeField] private TileBase waterTile;
    [SerializeField] private TileBase sandTile;
    [SerializeField] private TileBase grassTile;
    [SerializeField] private TileBase stoneTile;
    [SerializeField] private TileBase snowTile;

    [Header("Generation Settings")]
    [SerializeField] private int width = 100;
    [SerializeField] private int height = 100;
    [SerializeField] private int seed = 42;
    [SerializeField] private float scale = 30f;
    [SerializeField] private int octaves = 4;
    [SerializeField] private float persistence = 0.5f;
    [SerializeField] private float lacunarity = 2f;

    [Header("Height Thresholds")]
    [SerializeField] private float waterLevel = 0.3f;
    [SerializeField] private float sandLevel = 0.4f;
    [SerializeField] private float grassLevel = 0.7f;
    [SerializeField] private float stoneLevel = 0.85f;

    public void Generate()
    {
        tilemap.ClearAllTiles();

        var noiseMap = NoiseGenerator.GenerateNoiseMap(
            width, height, seed, scale, octaves, persistence, lacunarity, Vector2.zero);

        for (int y = 0; y < height; y++)
        {
            for (int x = 0; x < width; x++)
            {
                float value = noiseMap[x, y];
                TileBase tile = GetTileForHeight(value);
                tilemap.SetTile(new Vector3Int(x - width / 2, y - height / 2, 0), tile);
            }
        }
    }

    private TileBase GetTileForHeight(float height)
    {
        if (height < waterLevel) return waterTile;
        if (height < sandLevel) return sandTile;
        if (height < grassLevel) return grassTile;
        if (height < stoneLevel) return stoneTile;
        return snowTile;
    }
}

BSP Dungeon Generation

Binary Space Partition creates rectangular rooms connected by corridors. It produces clean, grid-aligned dungeons suitable for roguelikes and RPGs.

Algorithm Overview

1. Start with a large rectangle (the entire dungeon area).
2. Recursively split it in half (horizontally or vertically) until pieces reach minimum size.
3. Place a room inside each leaf partition (with random padding).
4. Connect sibling rooms with corridors.

Implementation

using System.Collections.Generic;
using UnityEngine;

public class BSPDungeon
{
    public class BSPNode
    {
        public RectInt Area;
        public BSPNode Left;
        public BSPNode Right;
        public RectInt? Room;

        public bool IsLeaf => Left == null && Right == null;
    }

    private int _minPartitionSize;
    private int _minRoomSize;
    private int _roomPadding;
    private SeededRandom _rng;

    private List<RectInt> _rooms = new();
    private HashSet<Vector2Int> _corridors = new();

    public IReadOnlyList<RectInt> Rooms => _rooms;
    public IReadOnlyCollection<Vector2Int> Corridors => _corridors;

    public BSPDungeon(int minPartitionSize = 10, int minRoomSize = 4, int roomPadding = 2)
    {
        _minPartitionSize = minPartitionSize;
        _minRoomSize = minRoomSize;
        _roomPadding = roomPadding;
    }

    public int[,] Generate(int width, int height, int seed)
    {
        _rng = new SeededRandom(seed);
        _rooms.Clear();
        _corridors.Clear();

        // 0 = wall, 1 = floor
        var grid = new int[width, height];

        // Build BSP tree
        var root = new BSPNode { Area = new RectInt(0, 0, width, height) };
        Split(root);

        // Place rooms in leaves
        PlaceRooms(root);

        // Connect rooms
        ConnectRooms(root);

        // Write rooms to grid
        foreach (var room in _rooms)
        {
            for (int x = room.x; x < room.x + room.width; x++)
                for (int y = room.y; y < room.y + room.height; y++)
                    grid[x, y] = 1;
        }

        // Write corridors to grid
        foreach (var pos in _corridors)
        {
            if (pos.x >= 0 && pos.x < width && pos.y >= 0 && pos.y < height)
                grid[pos.x, pos.y] = 1;
        }

        return grid;
    }

    private void Split(BSPNode node)
    {
        // Stop if too small to split
        if (node.Area.width < _minPartitionSize * 2 &&
            node.Area.height < _minPartitionSize * 2)
            return;

        // Choose split direction
        bool splitHorizontal;
        if (node.Area.width < _minPartitionSize * 2)
            splitHorizontal = true;
        else if (node.Area.height < _minPartitionSize * 2)
            splitHorizontal = false;
        else
            splitHorizontal = _rng.Chance(0.5f);

        if (splitHorizontal)
        {
            int splitY = _rng.Next(
                node.Area.y + _minPartitionSize,
                node.Area.y + node.Area.height - _minPartitionSize);

            node.Left = new BSPNode
            {
                Area = new RectInt(node.Area.x, node.Area.y,
                    node.Area.width, splitY - node.Area.y)
            };
            node.Right = new BSPNode
            {
                Area = new RectInt(node.Area.x, splitY,
                    node.Area.width, node.Area.y + node.Area.height - splitY)
            };
        }
        else
        {
            int splitX = _rng.Next(
                node.Area.x + _minPartitionSize,
                node.Area.x + node.Area.width - _minPartitionSize);

            node.Left = new BSPNode
            {
                Area = new RectInt(node.Area.x, node.Area.y,
                    splitX - node.Area.x, node.Area.height)
            };
            node.Right = new BSPNode
            {
                Area = new RectInt(splitX, node.Area.y,
                    node.Area.x + node.Area.width - splitX, node.Area.height)
            };
        }

        Split(node.Left);
        Split(node.Right);
    }

    private void PlaceRooms(BSPNode node)
    {
        if (node.IsLeaf)
        {
            int roomW = _rng.Next(_minRoomSize, node.Area.width - _roomPadding * 2);
            int roomH = _rng.Next(_minRoomSize, node.Area.height - _roomPadding * 2);
            int roomX = _rng.Next(node.Area.x + _roomPadding,
                node.Area.x + node.Area.width - roomW - _roomPadding);
            int roomY = _rng.Next(node.Area.y + _roomPadding,
                node.Area.y + node.Area.height - roomH - _roomPadding);

            var room = new RectInt(roomX, roomY, roomW, roomH);
            node.Room = room;
            _rooms.Add(room);
            return;
        }

        if (node.Left != null) PlaceRooms(node.Left);
        if (node.Right != null) PlaceRooms(node.Right);
    }

    private void ConnectRooms(BSPNode node)
    {
        if (node.IsLeaf) return;

        ConnectRooms(node.Left);
        ConnectRooms(node.Right);

        // Connect a room from left subtree to a room from right subtree
        var leftRoom = GetRoomFromSubtree(node.Left);
        var rightRoom = GetRoomFromSubtree(node.Right);

        if (leftRoom.HasValue && rightRoom.HasValue)
        {
            Vector2Int centerA = new Vector2Int(
                leftRoom.Value.x + leftRoom.Value.width / 2,
                leftRoom.Value.y + leftRoom.Value.height / 2);
            Vector2Int centerB = new Vector2Int(
                rightRoom.Value.x + rightRoom.Value.width / 2,
                rightRoom.Value.y + rightRoom.Value.height / 2);

            CreateCorridor(centerA, centerB);
        }
    }

    private RectInt? GetRoomFromSubtree(BSPNode node)
    {
        if (node.Room.HasValue) return node.Room;
        if (node.Left != null)
        {
            var r = GetRoomFromSubtree(node.Left);
            if (r.HasValue) return r;
        }
        if (node.Right != null) return GetRoomFromSubtree(node.Right);
        return null;
    }

    private void CreateCorridor(Vector2Int from, Vector2Int to)
    {
        // L-shaped corridor: horizontal then vertical (or vice versa)
        Vector2Int current = from;

        // Horizontal segment
        while (current.x != to.x)
        {
            _corridors.Add(current);
            // Add width to corridor
            _corridors.Add(current + Vector2Int.up);
            current.x += current.x < to.x ? 1 : -1;
        }

        // Vertical segment
        while (current.y != to.y)
        {
            _corridors.Add(current);
            _corridors.Add(current + Vector2Int.right);
            current.y += current.y < to.y ? 1 : -1;
        }
    }
}

Random Walk (Cave Generation)

A drunk walk algorithm for organic, cave-like spaces.

using System.Collections.Generic;
using UnityEngine;

public static class RandomWalkGenerator
{
    /// <summary>
    /// Generate cave-like floor positions using a random walk.
    /// </summary>
    public static HashSet<Vector2Int> DrunkWalk(
        Vector2Int startPos, int steps, int seed)
    {
        var rng = new SeededRandom(seed);
        var floorPositions = new HashSet<Vector2Int> { startPos };
        var current = startPos;

        Vector2Int[] directions = {
            Vector2Int.up, Vector2Int.down, Vector2Int.left, Vector2Int.right
        };

        for (int i = 0; i < steps; i++)
        {
            current += directions[rng.Next(0, 4)];
            floorPositions.Add(current);
        }

        return floorPositions;
    }

    /// <summary>
    /// Multiple random walks from the same origin for wider caves.
    /// </summary>
    public static HashSet<Vector2Int> MultiWalk(
        Vector2Int startPos, int walks, int stepsPerWalk, int seed)
    {
        var rng = new SeededRandom(seed);
        var allFloors = new HashSet<Vector2Int>();

        for (int w = 0; w < walks; w++)
        {
            var floors = DrunkWalk(startPos, stepsPerWalk, rng.Next(0, int.MaxValue));
            allFloors.UnionWith(floors);
        }

        return allFloors;
    }

    /// <summary>
    /// Corridor-constrained walk: bias in one direction for path-like caves.
    /// </summary>
    public static HashSet<Vector2Int> CorridorWalk(
        Vector2Int startPos, int length, Vector2Int primaryDirection, int seed,
        float straightChance = 0.7f)
    {
        var rng = new SeededRandom(seed);
        var positions = new HashSet<Vector2Int> { startPos };
        var current = startPos;

        Vector2Int[] perpendicular = primaryDirection.x != 0
            ? new[] { Vector2Int.up, Vector2Int.down }
            : new[] { Vector2Int.left, Vector2Int.right };

        for (int i = 0; i < length; i++)
        {
            if (rng.Chance(straightChance))
            {
                current += primaryDirection;
            }
            else
            {
                current += perpendicular[rng.Next(0, 2)];
            }
            positions.Add(current);
        }

        return positions;
    }
}

Weighted Random (Loot Tables)

A generic weighted random selection system. Essential for loot drops, enemy spawns, and any "pick one from a pool with different probabilities" scenario.

using System;
using System.Collections.Generic;

[Serializable]
public struct WeightedItem<T>
{
    public T item;
    public float weight;
}

public class WeightedRandom<T>
{
    private List<WeightedItem<T>> _items = new();
    private float _totalWeight;

    public void Add(T item, float weight)
    {
        _items.Add(new WeightedItem<T> { item = item, weight = weight });
        _totalWeight += weight;
    }

    public void AddRange(IEnumerable<WeightedItem<T>> items)
    {
        foreach (var item in items)
            Add(item.item, item.weight);
    }

    /// <summary>
    /// Pick one item based on weights. Uses System.Random for determinism.
    /// </summary>
    public T Pick(System.Random rng)
    {
        float roll = (float)rng.NextDouble() * _totalWeight;
        float cumulative = 0f;

        foreach (var entry in _items)
        {
            cumulative += entry.weight;
            if (roll <= cumulative)
                return entry.item;
        }

        // Fallback (floating point edge case)
        return _items[_items.Count - 1].item;
    }

    /// <summary>
    /// Pick N unique items (no repeats). For loot tables that drop multiple items.
    /// </summary>
    public List<T> PickMultipleUnique(int count, System.Random rng)
    {
        var result = new List<T>();
        var remaining = new List<WeightedItem<T>>(_items);
        float remainingWeight = _totalWeight;

        for (int i = 0; i < count && remaining.Count > 0; i++)
        {
            float roll = (float)rng.NextDouble() * remainingWeight;
            float cumulative = 0f;

            for (int j = 0; j < remaining.Count; j++)
            {
                cumulative += remaining[j].weight;
                if (roll <= cumulative)
                {
                    result.Add(remaining[j].item);
                    remainingWeight -= remaining[j].weight;
                    remaining.RemoveAt(j);
                    break;
                }
            }
        }

        return result;
    }
}

Loot Table ScriptableObject

using System;
using UnityEngine;

[Serializable]
public struct LootEntry
{
    public ItemDefinition item;
    public float weight;
    public int minCount;
    public int maxCount;
}

[CreateAssetMenu(fileName = "New Loot Table", menuName = "Loot/Loot Table")]
public class LootTable : ScriptableObject
{
    public LootEntry[] entries;
    public int minDrops = 1;
    public int maxDrops = 3;

    [Header("Guaranteed Drops")]
    public ItemDefinition[] guaranteedDrops;

    [Header("Pity System")]
    [Tooltip("After this many rolls without a rare drop, force one.")]
    public int pityThreshold = 20;
    public float rareWeightThreshold = 5f; // Items with weight below this are 'rare'

    public List<(ItemDefinition item, int count)> Roll(System.Random rng, int pityCounter = 0)
    {
        var result = new List<(ItemDefinition, int)>();

        // Guaranteed drops first
        foreach (var guaranteed in guaranteedDrops)
        {
            if (guaranteed != null)
                result.Add((guaranteed, 1));
        }

        // Random drops
        int dropCount = rng.Next(minDrops, maxDrops + 1);
        var table = new WeightedRandom<LootEntry>();

        foreach (var entry in entries)
        {
            float weight = entry.weight;

            // Pity system: boost rare item weights when pity counter is high
            if (pityCounter >= pityThreshold && weight <= rareWeightThreshold)
            {
                weight *= 3f; // Triple the chance of rare items
            }

            table.Add(entry, weight);
        }

        for (int i = 0; i < dropCount; i++)
        {
            var drop = table.Pick(rng);
            int count = rng.Next(drop.minCount, drop.maxCount + 1);
            result.Add((drop.item, count));
        }

        return result;
    }
}

Wave Function Collapse (Basics)

WFC generates tile layouts where every tile respects adjacency rules with its neighbors. It produces surprisingly coherent results for maps, buildings, and patterns.

Core Concept

1. Start with a grid where each cell can be any tile (all possibilities).
2. Find the cell with the fewest remaining possibilities (lowest entropy).
3. Collapse it: randomly pick one tile from its possibilities.
4. Propagate: remove impossible tiles from neighbors based on adjacency rules.
5. Repeat until all cells are collapsed (or a contradiction is hit).

Simplified Implementation

using System.Collections.Generic;
using System.Linq;
using UnityEngine;

[System.Serializable]
public class WFCTile
{
    public string tileId;
    public TileBase unityTile;
    public float weight = 1f;

    // Which tiles can be adjacent in each direction
    public string[] allowedUp;
    public string[] allowedDown;
    public string[] allowedLeft;
    public string[] allowedRight;

    public string[] GetAllowed(int direction)
    {
        return direction switch
        {
            0 => allowedUp,
            1 => allowedRight,
            2 => allowedDown,
            3 => allowedLeft,
            _ => null
        };
    }
}

public class WFCGenerator
{
    private int _width, _height;
    private List<WFCTile> _allTiles;
    private HashSet<string>[,] _possibilities;
    private string[,] _result;
    private System.Random _rng;

    private static readonly Vector2Int[] Directions = {
        Vector2Int.up, Vector2Int.right, Vector2Int.down, Vector2Int.left
    };

    private static readonly int[] Opposite = { 2, 3, 0, 1 };

    public string[,] Generate(int width, int height, List<WFCTile> tiles, int seed)
    {
        _width = width;
        _height = height;
        _allTiles = tiles;
        _rng = new System.Random(seed);
        _result = new string[width, height];
        _possibilities = new HashSet<string>[width, height];

        // Initialize: every cell can be any tile
        var allIds = tiles.Select(t => t.tileId).ToHashSet();
        for (int x = 0; x < width; x++)
            for (int y = 0; y < height; y++)
                _possibilities[x, y] = new HashSet<string>(allIds);

        // Iterate until fully collapsed
        while (true)
        {
            var cell = FindLowestEntropyCell();
            if (cell == null) break; // All collapsed

            Collapse(cell.Value);
            Propagate(cell.Value);
        }

        return _result;
    }

    private Vector2Int? FindLowestEntropyCell()
    {
        int minEntropy = int.MaxValue;
        Vector2Int? best = null;

        for (int x = 0; x < _width; x++)
        {
            for (int y = 0; y < _height; y++)
            {
                int count = _possibilities[x, y].Count;
                if (count <= 1) continue; // Already collapsed
                if (count < minEntropy)
                {
                    minEntropy = count;
                    best = new Vector2Int(x, y);
                }
            }
        }

        return best;
    }

    private void Collapse(Vector2Int pos)
    {
        // Weighted random selection from remaining possibilities
        var possible = _possibilities[pos.x, pos.y].ToList();
        var table = new WeightedRandom<string>();
        foreach (var id in possible)
        {
            var tile = _allTiles.First(t => t.tileId == id);
            table.Add(id, tile.weight);
        }

        string chosen = table.Pick(_rng);
        _possibilities[pos.x, pos.y] = new HashSet<string> { chosen };
        _result[pos.x, pos.y] = chosen;
    }

    private void Propagate(Vector2Int start)
    {
        var stack = new Stack<Vector2Int>();
        stack.Push(start);

        while (stack.Count > 0)
        {
            var current = stack.Pop();

            for (int d = 0; d < 4; d++)
            {
                var neighbor = current + Directions[d];
                if (neighbor.x < 0 || neighbor.x >= _width ||
                    neighbor.y < 0 || neighbor.y >= _height)
                    continue;

                // Compute which tiles the neighbor can be, given current cell's possibilities
                var allowedAtNeighbor = new HashSet<string>();
                foreach (var tileId in _possibilities[current.x, current.y])
                {
                    var tile = _allTiles.First(t => t.tileId == tileId);
                    foreach (var allowed in tile.GetAllowed(d))
                        allowedAtNeighbor.Add(allowed);
                }

                int before = _possibilities[neighbor.x, neighbor.y].Count;
                _possibilities[neighbor.x, neighbor.y].IntersectWith(allowedAtNeighbor);
                int after = _possibilities[neighbor.x, neighbor.y].Count;

                // If we reduced possibilities, propagate further
                if (after < before)
                {
                    if (after == 1)
                    {
                        _result[neighbor.x, neighbor.y] =
                            _possibilities[neighbor.x, neighbor.y].First();
                    }
                    if (after == 0)
                    {
                        Debug.LogWarning($"WFC contradiction at ({neighbor.x}, {neighbor.y})");
                        // Handle contradiction: restart or backtrack
                    }
                    stack.Push(neighbor);
                }
            }
        }
    }
}

WFC is powerful but the adjacency rules definition is the hard part. For simple projects, define rules manually. For complex tilesets, auto-derive rules from a sample image.

Object Placement: Poisson Disk Sampling

Place objects (trees, rocks, items) with natural-looking spacing. Unlike pure random placement, Poisson disk sampling guarantees a minimum distance between points.

using System.Collections.Generic;
using UnityEngine;

public static class PoissonDiskSampling
{
    public static List<Vector2> Generate(
        float width, float height, float minDistance, int seed, int maxAttempts = 30)
    {
        var rng = new System.Random(seed);
        float cellSize = minDistance / Mathf.Sqrt(2f);
        int gridW = Mathf.CeilToInt(width / cellSize);
        int gridH = Mathf.CeilToInt(height / cellSize);
        var grid = new int[gridW, gridH];
        for (int x = 0; x < gridW; x++)
            for (int y = 0; y < gridH; y++)
                grid[x, y] = -1;

        var points = new List<Vector2>();
        var activeList = new List<int>();

        // Start with a random point
        var initial = new Vector2(
            (float)rng.NextDouble() * width,
            (float)rng.NextDouble() * height);
        points.Add(initial);
        activeList.Add(0);
        grid[(int)(initial.x / cellSize), (int)(initial.y / cellSize)] = 0;

        while (activeList.Count > 0)
        {
            int activeIdx = rng.Next(0, activeList.Count);
            var point = points[activeList[activeIdx]];
            bool found = false;

            for (int attempt = 0; attempt < maxAttempts; attempt++)
            {
                float angle = (float)rng.NextDouble() * Mathf.PI * 2f;
                float dist = minDistance + (float)rng.NextDouble() * minDistance;
                var candidate = point + new Vector2(
                    Mathf.Cos(angle) * dist,
                    Mathf.Sin(angle) * dist);

                if (candidate.x < 0 || candidate.x >= width ||
                    candidate.y < 0 || candidate.y >= height)
                    continue;

                int cx = (int)(candidate.x / cellSize);
                int cy = (int)(candidate.y / cellSize);

                if (IsValid(candidate, grid, points, cellSize, minDistance, gridW, gridH))
                {
                    points.Add(candidate);
                    activeList.Add(points.Count - 1);
                    grid[cx, cy] = points.Count - 1;
                    found = true;
                    break;
                }
            }

            if (!found)
                activeList.RemoveAt(activeIdx);
        }

        return points;
    }

    private static bool IsValid(Vector2 candidate, int[,] grid, List<Vector2> points,
        float cellSize, float minDist, int gridW, int gridH)
    {
        int cx = (int)(candidate.x / cellSize);
        int cy = (int)(candidate.y / cellSize);

        for (int x = Mathf.Max(0, cx - 2); x <= Mathf.Min(gridW - 1, cx + 2); x++)
        {
            for (int y = Mathf.Max(0, cy - 2); y <= Mathf.Min(gridH - 1, cy + 2); y++)
            {
                int idx = grid[x, y];
                if (idx >= 0)
                {
                    if (Vector2.Distance(candidate, points[idx]) < minDist)
                        return false;
                }
            }
        }
        return true;
    }
}

Difficulty Scaling

Parameterize generation functions so difficulty ramps as the player progresses.

[System.Serializable]
public class DungeonDifficultyProfile
{
    public int floorNumber;
    public int minRooms;
    public int maxRooms;
    public float enemyDensity;       // Enemies per room
    public float eliteChance;         // Chance of elite enemy per spawn
    public float trapDensity;
    public LootTable lootTable;       // Better loot tables at higher floors
    public int minRoomSize;
    public int maxRoomSize;
}

public class DungeonGenerator : MonoBehaviour
{
    [SerializeField] private DungeonDifficultyProfile[] difficultyProfiles;

    public DungeonDifficultyProfile GetProfileForFloor(int floor)
    {
        // Find the profile that matches or interpolate between two
        for (int i = difficultyProfiles.Length - 1; i >= 0; i--)
        {
            if (floor >= difficultyProfiles[i].floorNumber)
                return difficultyProfiles[i];
        }
        return difficultyProfiles[0];
    }
}

Practical Tips

• Generate data, then render. Always separate generation logic (produces an int grid or list of positions) from rendering (applies tiles, spawns prefabs). This makes generation testable without Unity.
• Validate output. After generating a dungeon, flood-fill from the entrance to verify all rooms are reachable. If not, regenerate with a different seed.
• Generation budget. Complex generation can freeze the game. Run it in a coroutine (yield every N iterations) or on a background thread (for pure math, no Unity API calls).
• Preview in editor. Add [ContextMenu("Generate")] or a custom editor button to regenerate in edit mode. Fast iteration on generation parameters is essential.
• Combine techniques. Use BSP for room layout, random walk for cave-like connectors, noise for decorative detail within rooms, and Poisson disk for object placement.
• Save the seed, not the map. If generation is deterministic, you only need to save the seed and floor number to reconstruct the entire level. This keeps save files small.