Function write_line_of_sight 

pub fn write_line_of_sight(
    layout: &StartposLayout,
    parent: &str,
    grid: &VisionGrid,
    vision: Option<&Vision>,
) -> Result<RecordNode>

Writes a LINE_OF_SIGHT record under a parent record: whether it sees, the world bounds of what it sees and the area itself. Without an area, it sees nothing and has no area.

Errors

Returns an error if the layout lacks the records.