Algorithm 1 Edge acquisition in quads intersecting with line
Input: $root,p,q$
Output: $edgeSet$
1:	function LineIntersectPoly($p,q$)
2:	GetEdges$\left(node,p,q,edgeSet\right)$
3:	for $i$ = 1 to N  //N is the number of edges in $edgeSet$
4:	If $edgeSet\left[i\right]$ ${{\displaystyle \cap }}^{ }$ ($p,q$) then return true
5:	end for
6:	return false
7:	end function
8:	function GetEdges$\left(node,p,q,edgeSet\right)$
9:	if $node$.child $\ne \varnothing$ and $node$.edges $\ne \varnothing$ then
10:	$edgeSet$.append($node$.edges)
11:	else
12:	child = {NE, NW, SE, SW}
13:	for i = 1:4 do
14:	if $node.child\left[i\right]$.bound ${{\displaystyle \cap }}^{ }$ ($p,q$) then
15:	GetEdges$\left(node.child\left[i\right],p,q,edgeSet\right)$
16:	end if
17:	end for
18:	end if
19:	end function