public void AddDisturbance(Vector3 pos, float radius, float force)
        {
            int minX = GetGridIndex(pos.x - radius);
            int maxX = GetGridIndex(pos.x + radius);
            int minY = GetGridIndex(pos.z - radius);
            int maxY = GetGridIndex(pos.z + radius);

            for (int x = minX; x <= maxX; x++)
            {
                for (int y = minY; y <= maxY; y++)
                {
                    TerrainGrassTile tile = rollMap.Get(x, y);
                    if (tile)
                    {
                        tile.AddDisturbance(pos, radius, force);
                    }
                }
            }
        }