07/05/04 19:37:03
>>338
c1 = (y1-y2)*(a-x2)-(x1-x2)*(b-y2)
c2 = (y2-y3)*(a-x3)-(x2-x3)*(b-y3)
c3 = (y3-y1)*(a-x1)-(x3-x1)*(b-y1)
((c1<0)&&(c2<0)&&(c3<0)) || ((c1>0)&&(c2>0)&&(c3>0))
07/05/04 19:37:03
>>338
c1 = (y1-y2)*(a-x2)-(x1-x2)*(b-y2)
c2 = (y2-y3)*(a-x3)-(x2-x3)*(b-y3)
c3 = (y3-y1)*(a-x1)-(x3-x1)*(b-y1)
((c1<0)&&(c2<0)&&(c3<0)) || ((c1>0)&&(c2>0)&&(c3>0))