Is there any way to determine inner angle of twisted polygon? (Here's a picture of "normal" and "twisted" polygon http://courses.be.washington.edu/ARCH/481/1.Tapestry%20Reader/1.Data/6.Problems/graphics.invis/fulltwist.gif )
I know how to determine inner angle of polygon if I know its orientation (CW or CCW), however twisted polygon changes orientation after intersection, so if I check angle for CCW orientation, the CW part will have inverse angle values.
I thought about using winding numbers algorithm and see if values are negative or positive, but it is too slow to check that for every angle.