Camera position (revealing tiles that are on a higher level)

[Slime]

When there's a room that has a roof and you are standing like 2 squares away from it, the roof disappears and you can see what's inside the room. I wanted to change in a way that you'd have to stand directly under the roof to make it disappear. I guess this part of the code is responsible for this, no idea how to edit it though.
mapview.cpp

 // loop in 3x3 tiles around the camera
                for(int ix = -1; ix <= 1 && firstFloor < cameraPosition.z; ++ix) {
                    for(int iy = -1; iy <= 1 && firstFloor < cameraPosition.z; ++iy) {
                        Position pos = cameraPosition.translated(ix, iy);