Tilemap Index out of bounds collision

Question

I created my tile map and my player with movement.

I'm now trying to create the collision and I feel i'm on the right track.

Here is how I've created the map.

    List<Texture2D> tileTextures = new List<Texture2D>();
    int tileWidth = 60;
    int tileHeight = 60;

    public int[,] Map = new int[,]
        {
            {2,2,2,2,2,2,2,2,2,2},
            {2,2,2,2,1,2,2,2,2,2},
            {2,2,2,2,2,2,2,2,2,2},
            {2,2,2,2,2,2,2,2,2,2},
        };

  public void Draw(SpriteBatch spriteBatch)
    {
        int tileMapWidth = Map.GetLength(1);
        int tileMapHeight = Map.GetLength(0);

        for (int x = 0; x < tileMapWidth; x++)
        {
            for (int y = 0; y < tileMapHeight; y++)
            {
                int textureIndex = Map[y, x];
                Texture2D texture = tileTextures[textureIndex];

                spriteBatch.Draw(
                    texture,
                    source = new Rectangle(x *myTile.Width,
                        y * myTile.Height,
                        tileWidth,
                        tileHeight),
                    Color.White);
            }
        }
    }

I am checking the 2d array coords with this condition and checking to see if a specific tile is there, where I can then set my previous location if it is true.

I'm currently testing on 1 tile atm.

 public void Update(GameTime gameTime)
    {
        prevPosition = position;
        input(gameTime);

       if(tiles.Map[(int)playerPosition.X/60,(int)playerPosition.Y/60] == 1)
        {
            position = prevPosition;
        }
    }

However my player position keeps going out of the index bounds of the 2D array and I believe I need to scale it down so that it stops this, I've tried dividing the play coords by the width of the tiles but that hasn't worked.

If anyone can help me with the correct scaling I would be very appreciative.

Answer 1

This will happen if your player's position is like -x,y or x,-y or maybe -x,-y. Yor approach might be better if you'd make a fuction like this one

public bool CollidesWithWall(int x, int y)
{
    if(x < 0 || x > *matrix width* - 1) return false;
    if(y < 0 || y > *matrix height* -1) return false;
    if (Map[x,y] == 1) return true;
    return false;
}

and use it insead of the line tiles.Map[(int)playerPosition.X/60,(int)playerPosition.Y/60]

Or, if you need the type of tile returned

public int CollidesWithWall(int x, int y)
{
    if(x < 0 || x > *matrix width* - 1) return -1;
    if(y < 0 || y > *matrix height* -1) return -1;
    return Map[x,y];
}

By doing it this way, you'll know if you stumbled upon a health potion (just set it's ID to like 3) or a wall (with ID of 1 or something, that's tottaly up to you) and if it is 0, it's empty space (or maybe -1). Notice that the "-1" part is totaly up to you. Just write down a list of id's that youll have and which items they present.

Other suggestions
Try if(tiles.Map[(int)(playerPosition.X/60f),(int)(playerPosition.Y/60f)] == 1)