Michel Dänzer wrote: > On Sun, 2008-02-17 at 14:51 +0100, Claudio Ciccani wrote: >> Il giorno sab, 16/02/2008 alle 19.30 +0100, Denis Oliver Kropp ha >> scritto: >>> Claudio Ciccani wrote: >>>> You written FillTrapezoid(), my brain received FillPolygon()!! >>> FillPolygon() would be the toplevel, but if I made up my UI from a bunch >>> of quadrangles calling FillQuadrangles(), it would be much more efficient >>> than a generic FillPolygon() which most likely has to tesselate your polygon >>> using triangles, trapezoids or quadrangles. Well, it could be cached, and >>> end up at the same thing, but if your polygons are changing too much or you >>> have a lot of them coming and going, it would be better to use quadrangles, >>> which would only need to be splitted in case the hardware only does >>> triangles, >>> or split up a second time for trapezoid based rasterizers, like Matrox >>> G-series. >>> >>> Maybe I missed something and hardware directly supports arbitrary Polygons >>> nowadays. >> OpenGL 1.1 compliant cards support polygon rendering (GL_POLYGON) and >> polygon antialiasing (GL_POLYGON_SMOOTH); [...] > > Hardware still only supports triangles though. The GL implementation > decomposes polygons into simpler primitives but only guarantees to do it > correctly for simple, convex polygons.
That's what I thought. So still I think adding FillQuadrangles() would be the best choice for current hardware and software, e.g. to implement Cairo's trapezoids. SH7722 supports quadrangles directly and for the 3D enhanced DirectFB drivers it would be a triangle fan. -- Best regards, Denis Oliver Kropp .------------------------------------------. | DirectFB - Hardware accelerated graphics | | http://www.directfb.org/ | "------------------------------------------" _______________________________________________ directfb-dev mailing list directfb-dev@directfb.org http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-dev
