   OpenGL non-convex polygon... question
  Hello everyone!Im currently doing a project that involves drawing any kind of a three-dimensional polygon.That will include drawing a non-covex type. Some articles that I've read state that drawing a non-convex polygon is not possible using GL_POLYGON function. However, when I try to draw a convex 2d plane(this is one of the planes in the three-dimensional polygon), it displays the polygon correctly. But when I try to draw all the 2d polygons to make up the 3d convex polygon, the polygon somehow become distorted...Do you have any idea what is happening to my program?Does OpenGL support drawing non-convex polygons?Please help me...Thank you very much...Btw, Im using Mesa3d 6.4.1 in mandrakelinux 10.1   
  break the polygons down into triangles by using a triangle fan. some of the clipping algorithms used break when using non convex polygons. using polygons is kind of depreciated most cases opengl hardware breaks then down to triangles anyway and it requires an additional step so just use a triangle fan.   