You can check point in poly with 100% precision by testing which side of each line the point is on. If it is on the inside side of all three, then the point is in the poly.
I think there is a point in poly gunction in the code archives that I put there. But I know there is a function I put there which tells you which side of a line you are on. The code is B3D code, but it is easy enough for you to port.
Actually, going back over it again, the method you describe sounds pretty similar to this method. But you test the dot product of the point and the line's normal, not the vertices. A distance check might speed things up a little, but if you're talking an interface then it is totally uneccessary to optimize it. There's no way you'd test even 1/100000th of the number of polygons you would need to for it to matter.
I think there is a point in poly gunction in the code archives that I put there. But I know there is a function I put there which tells you which side of a line you are on. The code is B3D code, but it is easy enough for you to port.
Actually, going back over it again, the method you describe sounds pretty similar to this method. But you test the dot product of the point and the line's normal, not the vertices. A distance check might speed things up a little, but if you're talking an interface then it is totally uneccessary to optimize it. There's no way you'd test even 1/100000th of the number of polygons you would need to for it to matter.