GLUTESSBEGINPOLYGON(3G) OpenGL Manual GLUTESSBEGINPOLYGON(3G)
NAME
gluTessBeginPolygon - delimit a polygon description
C SPECIFICATION
void gluTessBeginPolygon(GLUtesselator* tess, GLvoid* data);
PARAMETERS
tess
Specifies the tessellation object (created with gluNewTess()).
data
Specifies a pointer to user polygon data.
DESCRIPTION
gluTessBeginPolygon and gluTessEndPolygon() delimit the definition of a convex, concave or self-intersecting polygon. Within each
gluTessBeginPolygon/gluTessEndPolygon() pair, there must be one or more calls to gluTessBeginContour()/gluTessEndContour(). Within each
contour, there are zero or more calls to gluTessVertex(). The vertices specify a closed contour (the last vertex of each contour is
automatically linked to the first). See the gluTessVertex(), gluTessBeginContour(), and gluTessEndContour() reference pages for more
details.
data is a pointer to a user-defined data structure. If the appropriate callback(s) are specified (see gluTessCallback()), then this pointer
is returned to the callback function(s). Thus, it is a convenient way to store per-polygon information.
Once gluTessEndPolygon() is called, the polygon is tessellated, and the resulting triangles are described through callbacks. See
gluTessCallback() for descriptions of the callback functions.
EXAMPLE
A quadrilateral with a triangular hole in it can be described as follows:
gluTessBeginPolygon(tobj, NULL);
gluTessBeginContour(tobj);
gluTessVertex(tobj, v1, v1);
gluTessVertex(tobj, v2, v2);
gluTessVertex(tobj, v3, v3);
gluTessVertex(tobj, v4, v4);
gluTessEndContour(tobj);
gluTessBeginContour(tobj);
gluTessVertex(tobj, v5, v5);
gluTessVertex(tobj, v6, v6);
gluTessVertex(tobj, v7, v7);
gluTessEndContour(tobj);
gluTessEndPolygon(tobj);
SEE ALSO
gluNewTess(), gluTessBeginContour(), gluTessCallback(), gluTessEndPolygon(), gluTessNormal(), gluTessProperty(), gluTessVertex()
COPYRIGHT
Copyright (C) 1991-2006 Silicon Graphics, Inc. This document is licensed under the SGI Free Software B License. For details, see
http://oss.sgi.com/projects/FreeB/.
AUTHORS
opengl.org
opengl.org 06/10/2014 GLUTESSBEGINPOLYGON(3G)
