Board Thread:Program Announcements/@comment-25017421-20140603081447/@comment-5334617-20141126033846

I think there is a bug in the lines

IF TRIP(1,1)-TRIP(0,1)>0 THEN GOSUB @ISLOPE1CALC ELSE ISLOPE1 = 0 IF TRIP(2,1)-TRIP(0,1)>0 THEN GOSUB @ISLOPE2CALC ELSE ISLOPE2 = 0

is the inverse slope of the line connecting vertex 0 of the triangle to vertex 1 of the triangle, that is, the delta x divided by the delta y (regular slope is delta y divided by delta x). The guard on the  statements are necessary to avoid division by zero, but if , for instance, that means the line is horizontal and the inverse slope is undefined. Setting  to   represents a vertical line. The next line, then,, does not properly distinguish between the cases when the line from 0 to 1 is "to the left of" or "to the right of" the line from 0 to 2.