marc@aplvax.UUCP (Marcus H. Gates) (05/27/87)
I am attempting to draw filled maps on a Silicon Graphics 2400-turbo
workstation and need an algorithm or two. We have World databases I and II
and have a program that for a given center and plotsize extracts all
line-segments in that window and attempts to contruct polygons which can
then be filled. In order to draw filled polygons on the Silicon Graphics beast
the polygons must be convex, so I also have software which splits concave into
multiple convex. One problem with that splitting algorithm is that when the
number of vertices is large ( > 100) it is really slow. The two algorithms I
need are:
1) Routine to split initial polygon into multiple polygons of size
less than some MAX value, these smaller polygons could then be
passed to the concave-convex code.
2) Routine to given an "alleged" polygon verify that it is indeed
a good polygon (doesn't intersect itself).
Any pointers would be greatly appreciated.