MapUtil.GetBorderPoints C# (CSharp) Method

    public static ICollection<Vec2> GetBorderPoints(float x, float y, float w, float h)
    {
        List<Vec2> points = new List<Vec2> ();

        int left = GetLeftBorder (x);
        int right = GetRightBorder (w);
        int lower = GetLowerBorder (y);
        int upper = GetUpperBorder (h);

        for (int i = left; i <= right; i++) {
            points.Add (new Vec2 (i, lower));
            points.Add (new Vec2 (i, upper));
        }

        for (int j = lower - 1; j < upper; j++) {
            points.Add (new Vec2 (left, j));
            points.Add (new Vec2 (right, j));
        }

        return points;
    }

    public ICollection <Vec2> GetTilesToLoad(float x, float y, float w, float h, int m, int n)
    {
        ICollection <Vec2> visibleTiles = lazyLoader.GetTilesToLoad(x, y, w, h, m, n);
        List <Vec2>        tiles        = new List <Vec2> (visibleTiles);

        Rect    rect     = new Rect(x, y, w - x, h - y);
        Vector2 newPivot = new Vector2(x, y);
        Vector2 delta    = newPivot - lastPivot;
        Vector2 normal   = delta.normalized;

        lastPivot = newPivot;

        foreach (var point in MapUtil.GetBorderPoints(x, y, w, h))
        {
            Vector2 checkPoint = new Vector2(point.x + delta.x, point.y + delta.y);
            if (!rect.Contains(checkPoint))
            {
                foreach (var potentialPoint in GetPotentialTiles(point, normal))
                {
                    if (potentialPoint.x >= 0 && potentialPoint.x < m &&
                        potentialPoint.y >= 0 && potentialPoint.y < n)
                    {
                        tiles.Add(potentialPoint);
                    }
                }
            }
        }

        return(tiles);
    }