Two polygon fill algorithms are presented for filling polygons on a graphics display. The first polygon fill algorithm fills polygons that are strictly convex. The second polygon fill algorithm fills a larger class of polygons than the first polygon fill algorithm which includes polygons being concave...http://www.google.co.uk/patents/US5710578?utm_source=gb-gplus-sharePatent US5710578 - Computer program product for utilizing fast polygon fill routines in a graphics display system 
