MapGenerator.cs

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

public enum BlockMaterial { GRASS, SAND, WATER }

public class MapGenerator : MonoBehaviour
{
  public Tilemap map;
  public Vector2 mapSize = new Vector2(100, 100);
  public int seed = -1;
  public float detailScale = 1;
  public float heightScale = 1;
  public Block[] availableBlocks;

  // Use this for initialization
  void Start()
  {
    if (seed < 0)
    {
      seed = Random.Range(0, 9999) + Random.Range(0, 9999) + Random.Range(0, 9999) + Random.Range(0, 9999);
      Debug.Log("Generate seed : " + seed);
    }

    for (int x = 0; x < mapSize.x; x++)
    {
      for (int y = 0; y < mapSize.y; y++)
      {
        int height = (int)(Mathf.PerlinNoise((x + seed) / detailScale, (y + seed) / detailScale) * heightScale);

        Debug.Log(x + "," + y + " : " + height);

        foreach (Block block in availableBlocks)
        {
          if (height <= block.minHeight)
          {
            Vector3Int pos = new Vector3Int(x, y, (int)map.transform.position.z);
            map.SetTile(pos, block.tile);
          }
        }
      }
    }
  }


  [System.Serializable]
  public struct Block
  {
    public BlockMaterial type;
    public int minHeight;
    public Tile tile;
  }
}