Terraria.Player.UpdateTouchingTiles C# (CSharp) Method

        public void UpdateTouchingTiles()
        {
            this.TouchedTiles.Clear();
            List<Point> list1 = (List<Point>)null;
            List<Point> list2 = (List<Point>)null;
            if (!Collision.IsClearSpotHack(this.position + this.velocity, 16f, this.width, this.height, false, false, (int)this.gravDir, true, true))
                list1 = Collision.FindCollisionTile(Math.Sign(this.velocity.Y) == 1 ? 2 : 3, this.position + this.velocity, 16f, this.width, this.height, false, false, (int)this.gravDir, true, false);
            if (!Collision.IsClearSpotHack(this.position, Math.Abs(this.velocity.Y), this.width, this.height, false, false, (int)this.gravDir, true, true))
                list2 = Collision.FindCollisionTile(Math.Sign(this.velocity.Y) == 1 ? 2 : 3, this.position, Math.Abs(this.velocity.Y), this.width, this.height, false, false, (int)this.gravDir, true, true);
            if (list1 != null && list2 != null)
            {
                for (int index = 0; index < list2.Count; ++index)
                {
                    if (!list1.Contains(list2[index]))
                        list1.Add(list2[index]);
                }
            }
            if (list1 == null && list2 != null)
                list1 = list2;
            if (list1 == null)
                return;
            this.TouchedTiles = list1;
        }