Polygon Fill Areas Implementation consideration Some graphics packages including OpenGL, only support convex polygon for the fill algorithms. Generate a line segment For degenerate(退化) polygogerlapping edges. or edges with o. leng A set of vertices that are collinear(or that have repeated vertex positions To identify these cases, graphics systems usually leave these to the ● For concave polygons Implementation of fill algorithms and other graphics routines aremore complicated for concave polygons olit a concave polygon into a set of convex polygonsPolygon Fill Areas  Implementation consideration  Some graphics packages including OpenGL, only support convex polygon for the fillalgorithms.  For degenerate (退化)polygons -- A set of vertices that are collinear (or that have repeated vertexpositions) --To identify these cases, graphics systems usually leave these to the programmer  For concave polygons -- Implementation of fill algorithms and other graphics routines aremore complicated for concave polygons --To split a concave polygon into a set of convex polygons Generate a line segment Overlapping edges, or edges with 0 length 7