making the damage lower with distence it easy. But picking units in an EXACT cone requires advanced maths. You need to make a group of all units infront of the caster with the circle being its radius away infront of the caster and having a wide enough radius that the 2 edges of the cone touch the edge of the other side of the circle. Then using advanced trigonomitry it must filter all the picked units to only thoughs that fit in the cone. After that you just need to get the distence away from the caster the unit is and culculate the damage.
Uhhh... that would work, but I would go with a much simpler route. Bases of off breath of fire. This has a buff. So, when you cast the ability, check for all units with the buff and then deal damage based on the distance from the caster. This method involves very little math and no complex cone/circle thing. Hope this helps...
Doesnt it only give the buff if the unit is effected by drunken haze though?