Cave MapGen with spawn items method

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

public class MapGenerator : MonoBehaviour {

    public int mapWidth;
    public int mapHeight;

    public string seed;
    public bool useRandomSeed;

    [Range(0,100)]
    public int randomFillPercent;

    int[,] map;

    public GameObject[] spawnObjectPrefabs;
    public int num = 10;
    public int wallDst = 3;

    void SpawnItems(GameObject[] spawn_items, int spawn_num, int spawn_itemDistThreshold, int spawn_distToWall, string spawn_holderName)
    {
        System.Random prng = new System.Random (seed.GetHashCode());
        List<Vector3> possibleSpawnPoints = new List<Vector3>();
        List<Coord> possibleSpawnCoord = new List<Coord>();

        for (int i = 0; i < map.GetLength(0); i++)
        {
            for (int j = 0; j < map.GetLength(1); j++)
            {
                if (map[i, j] == 0)
                {
                    possibleSpawnPoints.Add(new Vector3(-mapWidth / 2 + i, 0, -mapHeight / 2 + j));
                    possibleSpawnCoord.Add(new Coord(i, j));
                }
            }
        }
        if (GameObject.Find(spawn_holderName))
        {
            GameObject.Destroy(GameObject.Find(spawn_holderName));
        }
        GameObject holder = new GameObject(spawn_holderName);


        List<Vector3> spawnedPositions = new List<Vector3>();
        int safeCount = 50 * spawn_num;
        while (spawn_num > 0 && safeCount > 0)
        {
            int spawnIndex = prng.Next(0, possibleSpawnPoints.Count);
            Vector3 spawnLocation = possibleSpawnPoints[spawnIndex];
            Coord spawnCoord = possibleSpawnCoord[spawnIndex];

            bool itemTooCloseToPreviousSpawns = false;
            foreach (Vector3 v in spawnedPositions)
            {
                if (Vector3.SqrMagnitude(v - spawnLocation) < spawn_itemDistThreshold * spawn_itemDistThreshold)
                {
                    itemTooCloseToPreviousSpawns = true;
                    break;
                }
            }

            bool itemTooCloseToWalls = false;
            if (!itemTooCloseToWalls) {
                for (int i = -spawn_distToWall; i <= spawn_distToWall; i++) {
                    for (int j = -spawn_distToWall; j <= spawn_distToWall; j++)
                    {
                        int wallCheckX = spawnCoord.tileX + i;
                        int wallCheckY = spawnCoord.tileY + j;

                        if (wallCheckX >= 0 && wallCheckX < mapWidth && wallCheckY >= 0 && wallCheckY < mapHeight)
                        {
                            if (map[wallCheckX, wallCheckY] == 1)
                            {
                                itemTooCloseToWalls = true;
                                break;
                            }
                        }
                    }
                    if (itemTooCloseToWalls)
                    {
                        break;
                    }
                }
            }

            if (!itemTooCloseToPreviousSpawns && !itemTooCloseToWalls)
            {
                spawnedPositions.Add(spawnLocation);
                GameObject spawnedObject = Instantiate(spawn_items[UnityEngine.Random.Range(0, spawn_items.Length)].gameObject, spawnLocation, Quaternion.identity) as GameObject;
                spawnedObject.transform.Rotate(Vector3.right * 90);
                spawnedObject.transform.parent = holder.transform;
                spawn_num--;
            }
            safeCount--;
        }
        holder.transform.Rotate(Vector3.right * 270);
    }


    void Start() {
        GenerateMap();
    }

    void Update() {
        if (Input.GetMouseButtonDown(0)) {
            GenerateMap();
        }
    }

    void GenerateMap() {
        map = new int[mapWidth,mapHeight];
        RandomFillMap();

        for (int i = 0; i < 5; i ++) {
            SmoothMap();
        }

        ProcessMap ();

        int borderSize = 1;
        int[,] borderedMap = new int[mapWidth + borderSize * 2,mapHeight + borderSize * 2];

        for (int x = 0; x < borderedMap.GetLength(0); x ++) {
            for (int y = 0; y < borderedMap.GetLength(1); y ++) {
                if (x >= borderSize && x < mapWidth + borderSize && y >= borderSize && y < mapHeight + borderSize) {
                    borderedMap[x,y] = map[x-borderSize,y-borderSize];
                }
                else {
                    borderedMap[x,y] =1;
                }
            }
        }

        SpawnItems (spawnObjectPrefabs, num, 1, wallDst, "Holder");

        MeshGenerator meshGen = GetComponent<MeshGenerator>();
        meshGen.GenerateMesh(borderedMap, 1);
    }

    void ProcessMap() {
        List<List<Coord>> wallRegions = GetRegions (1);
        int wallThresholdSize = 50;

        foreach (List<Coord> wallRegion in wallRegions) {
            if (wallRegion.Count < wallThresholdSize) {
                foreach (Coord tile in wallRegion) {
                    map[tile.tileX,tile.tileY] = 0;
                }
            }
        }

        List<List<Coord>> roomRegions = GetRegions (0);
        int roomThresholdSize = 50;
        List<Room> survivingRooms = new List<Room> ();

        foreach (List<Coord> roomRegion in roomRegions) {
            if (roomRegion.Count < roomThresholdSize) {
                foreach (Coord tile in roomRegion) {
                    map[tile.tileX,tile.tileY] = 1;
                }
            }
            else {
                survivingRooms.Add(new Room(roomRegion, map));
            }
        }
        survivingRooms.Sort ();
        survivingRooms [0].isMainRoom = true;
        survivingRooms [0].isAccessibleFromMainRoom = true;

        ConnectClosestRooms (survivingRooms);
    }

    void ConnectClosestRooms(List<Room> allRooms, bool forceAccessibilityFromMainRoom = false) {

        List<Room> roomListA = new List<Room> ();
        List<Room> roomListB = new List<Room> ();

        if (forceAccessibilityFromMainRoom) {
            foreach (Room room in allRooms) {
                if (room.isAccessibleFromMainRoom) {
                    roomListB.Add (room);
                } else {
                    roomListA.Add (room);
                }
            }
        } else {
            roomListA = allRooms;
            roomListB = allRooms;
        }

        int bestDistance = 0;
        Coord bestTileA = new Coord ();
        Coord bestTileB = new Coord ();
        Room bestRoomA = new Room ();
        Room bestRoomB = new Room ();
        bool possibleConnectionFound = false;

        foreach (Room roomA in roomListA) {
            if (!forceAccessibilityFromMainRoom) {
                possibleConnectionFound = false;
                if (roomA.connectedRooms.Count > 0) {
                    continue;
                }
            }

            foreach (Room roomB in roomListB) {
                if (roomA == roomB || roomA.IsConnected(roomB)) {
                    continue;
                }

                for (int tileIndexA = 0; tileIndexA < roomA.edgeTiles.Count; tileIndexA ++) {
                    for (int tileIndexB = 0; tileIndexB < roomB.edgeTiles.Count; tileIndexB ++) {
                        Coord tileA = roomA.edgeTiles[tileIndexA];
                        Coord tileB = roomB.edgeTiles[tileIndexB];
                        int distanceBetweenRooms = (int)(Mathf.Pow (tileA.tileX-tileB.tileX,2) + Mathf.Pow (tileA.tileY-tileB.tileY,2));

                        if (distanceBetweenRooms < bestDistance || !possibleConnectionFound) {
                            bestDistance = distanceBetweenRooms;
                            possibleConnectionFound = true;
                            bestTileA = tileA;
                            bestTileB = tileB;
                            bestRoomA = roomA;
                            bestRoomB = roomB;
                        }
                    }
                }
            }
            if (possibleConnectionFound && !forceAccessibilityFromMainRoom) {
                CreatePassage(bestRoomA, bestRoomB, bestTileA, bestTileB);
            }
        }

        if (possibleConnectionFound && forceAccessibilityFromMainRoom) {
            CreatePassage(bestRoomA, bestRoomB, bestTileA, bestTileB);
            ConnectClosestRooms(allRooms, true);
        }

        if (!forceAccessibilityFromMainRoom) {
            ConnectClosestRooms(allRooms, true);
        }
    }

    void CreatePassage(Room roomA, Room roomB, Coord tileA, Coord tileB) {
        Room.ConnectRooms (roomA, roomB);
        //Debug.DrawLine (CoordToWorldPoint (tileA), CoordToWorldPoint (tileB), Color.green, 100);

        List<Coord> line = GetLine (tileA, tileB);
        foreach (Coord c in line) {
            DrawCircle(c,5);
        }
    }

    void DrawCircle(Coord c, int r) {
        for (int x = -r; x <= r; x++) {
            for (int y = -r; y <= r; y++) {
                if (x*x + y*y <= r*r) {
                    int drawX = c.tileX + x;
                    int drawY = c.tileY + y;
                    if (IsInMapRange(drawX, drawY)) {
                        map[drawX,drawY] = 0;
                    }
                }
            }
        }
    }

    List<Coord> GetLine(Coord from, Coord to) {
        List<Coord> line = new List<Coord> ();

        int x = from.tileX;
        int y = from.tileY;

        int dx = to.tileX - from.tileX;
        int dy = to.tileY - from.tileY;

        bool inverted = false;
        int step = Math.Sign (dx);
        int gradientStep = Math.Sign (dy);

        int longest = Mathf.Abs (dx);
        int shortest = Mathf.Abs (dy);

        if (longest < shortest) {
            inverted = true;
            longest = Mathf.Abs(dy);
            shortest = Mathf.Abs(dx);

            step = Math.Sign (dy);
            gradientStep = Math.Sign (dx);
        }

        int gradientAccumulation = longest / 2;
        for (int i =0; i < longest; i ++) {
            line.Add(new Coord(x,y));

            if (inverted) {
                y += step;
            }
            else {
                x += step;
            }

            gradientAccumulation += shortest;
            if (gradientAccumulation >= longest) {
                if (inverted) {
                    x += gradientStep;
                }
                else {
                    y += gradientStep;
                }
                gradientAccumulation -= longest;
            }
        }

        return line;
    }

    Vector3 CoordToWorldPoint(Coord tile) {
        return new Vector3 (-mapWidth / 2 + .5f + tile.tileX, 2, -mapHeight / 2 + .5f + tile.tileY);
    }

    List<List<Coord>> GetRegions(int tileType) {
        List<List<Coord>> regions = new List<List<Coord>> ();
        int[,] mapFlags = new int[mapWidth,mapHeight];

        for (int x = 0; x < mapWidth; x ++) {
            for (int y = 0; y < mapHeight; y ++) {
                if (mapFlags[x,y] == 0 && map[x,y] == tileType) {
                    List<Coord> newRegion = GetRegionTiles(x,y);
                    regions.Add(newRegion);

                    foreach (Coord tile in newRegion) {
                        mapFlags[tile.tileX, tile.tileY] = 1;
                    }
                }
            }
        }

        return regions;
    }

    List<Coord> GetRegionTiles(int startX, int startY) {
        List<Coord> tiles = new List<Coord> ();
        int[,] mapFlags = new int[mapWidth,mapHeight];
        int tileType = map [startX, startY];

        Queue<Coord> queue = new Queue<Coord> ();
        queue.Enqueue (new Coord (startX, startY));
        mapFlags [startX, startY] = 1;

        while (queue.Count > 0) {
            Coord tile = queue.Dequeue();
            tiles.Add(tile);

            for (int x = tile.tileX - 1; x <= tile.tileX + 1; x++) {
                for (int y = tile.tileY - 1; y <= tile.tileY + 1; y++) {
                    if (IsInMapRange(x,y) && (y == tile.tileY || x == tile.tileX)) {
                        if (mapFlags[x,y] == 0 && map[x,y] == tileType) {
                            mapFlags[x,y] = 1;
                            queue.Enqueue(new Coord(x,y));
                        }
                    }
                }
            }
        }
        return tiles;
    }

    bool IsInMapRange(int x, int y) {
        return x >= 0 && x < mapWidth && y >= 0 && y < mapHeight;
    }


    void RandomFillMap() {
        if (useRandomSeed) {
            seed = Time.time.ToString();
        }

        System.Random pseudoRandom = new System.Random(seed.GetHashCode());

        for (int x = 0; x < mapWidth; x ++) {
            for (int y = 0; y < mapHeight; y ++) {
                if (x == 0 || x == mapWidth-1 || y == 0 || y == mapHeight -1) {
                    map[x,y] = 1;
                }
                else {
                    map[x,y] = (pseudoRandom.Next(0,100) < randomFillPercent)? 1: 0;
                }
            }
        }
    }

    void SmoothMap() {
        for (int x = 0; x < mapWidth; x ++) {
            for (int y = 0; y < mapHeight; y ++) {
                int neighbourWallTiles = GetSurroundingWallCount(x,y);

                if (neighbourWallTiles > 4)
                    map[x,y] = 1;
                else if (neighbourWallTiles < 4)
                    map[x,y] = 0;

            }
        }
    }

    int GetSurroundingWallCount(int gridX, int gridY) {
        int wallCount = 0;
        for (int neighbourX = gridX - 1; neighbourX <= gridX + 1; neighbourX ++) {
            for (int neighbourY = gridY - 1; neighbourY <= gridY + 1; neighbourY ++) {
                if (IsInMapRange(neighbourX,neighbourY)) {
                    if (neighbourX != gridX || neighbourY != gridY) {
                        wallCount += map[neighbourX,neighbourY];
                    }
                }
                else {
                    wallCount ++;
                }
            }
        }

        return wallCount;
    }

    struct Coord {
        public int tileX;
        public int tileY;

        public Coord(int x, int y) {
            tileX = x;
            tileY = y;
        }
    }


    class Room : IComparable<Room> {
        public List<Coord> tiles;
        public List<Coord> edgeTiles;
        public List<Room> connectedRooms;
        public int roomSize;
        public bool isAccessibleFromMainRoom;
        public bool isMainRoom;

        public Room() {
        }

        public Room(List<Coord> roomTiles, int[,] map) {
            tiles = roomTiles;
            roomSize = tiles.Count;
            connectedRooms = new List<Room>();

            edgeTiles = new List<Coord>();
            foreach (Coord tile in tiles) {
                for (int x = tile.tileX-1; x <= tile.tileX+1; x++) {
                    for (int y = tile.tileY-1; y <= tile.tileY+1; y++) {
                        if (x == tile.tileX || y == tile.tileY) {
                            if (map[x,y] == 1) {
                                edgeTiles.Add(tile);
                            }
                        }
                    }
                }
            }
        }

        public void SetAccessibleFromMainRoom() {
            if (!isAccessibleFromMainRoom) {
                isAccessibleFromMainRoom = true;
                foreach (Room connectedRoom in connectedRooms) {
                    connectedRoom.SetAccessibleFromMainRoom();
                }
            }
        }

        public static void ConnectRooms(Room roomA, Room roomB) {
            if (roomA.isAccessibleFromMainRoom) {
                roomB.SetAccessibleFromMainRoom ();
            } else if (roomB.isAccessibleFromMainRoom) {
                roomA.SetAccessibleFromMainRoom();
            }
            roomA.connectedRooms.Add (roomB);
            roomB.connectedRooms.Add (roomA);
        }

        public bool IsConnected(Room otherRoom) {
            return connectedRooms.Contains(otherRoom);
        }

        public int CompareTo(Room otherRoom) {
            return otherRoom.roomSize.CompareTo (roomSize);
        }
    }

}