If there are two dense tiles that are next to each other diagonally so that they only touch at the corners, light cannot pass through the infinitely small gap in between them (as shown by your line of sight check). However, a player can easily just walk right through the gap and emerge on the other side of the tiles. This is a contradiction.

Expected Results: If the line of sight shows that you can't even see through these two dense tiles, then in theory you shouldn't be able to walk right through them either.

Actual Results: You walk right through, as if they were nothing at all.


Workarounds: Every time a player moves diagonally you have to implement checks to make sure they are not trying to move through two dense tiles in such a manner. But this really shouldn't be something we have to code, it should be a low level thing.