Casting corners

Hello,

I have been encountering an issue lately, when trying to cast rays on a grid :

it seems my corners aren’t properly being detected. My corners either partly overlap, or there might be a gap in the corner which one can see through. I think the issue may be due to some rounding errors (which makes either vertical or horizontal intersections be detected when they shouldn’t, or not be detected when they should).

Does anyone have any idea how to workaround this ? I’d like to be able to texture my world and I won’t be able to properly do so until the corners stop overlapping.