Before making a ranged combat attack, you must
determine if the attacker can draw a line of fire to
the target and if the target is within range.
If the line of fire is blocked, the attacker can’t
make a ranged combat attack against that target.
Any line of fire that isn’t blocked can be drawn. If a
line of fire can be drawn, count the shortest route
to the target in squares using the imaginary line
as a guide. Do not count the square the attacker
occupies when determining range.