Digital Equipment Corporation OpenGL man pages

gluBeginPolygon.3gl (Obsolete in GLU version 1.2 and later)


  gluBeginPolygon, gluEndPolygon - delimit a polygon description

C Specification

  void gluBeginPolygon(	GLUtesselator *tess )

  void gluEndPolygon( GLUtesselator *tess )


  tess	Specifies the tessellation object (created with	gluNewTess).


  gluBeginPolygon and gluEndPolygon delimit the	definition of a	nonconvex
  polygon.  To define such a polygon, first call gluBeginPolygon.  Then
  define the contours of the polygon by	calling	gluTessVertex for each vertex
  and gluNextContour to	start each new contour.	 Finally, call gluEndPolygon
  to signal the	end of the definition.	See the	gluTessVertex and
  gluNextContour reference pages for more details.

  Once gluEndPolygon is	called,	the polygon is tessellated, and	the resulting
  triangles are	described through callbacks.  See gluTessCallback for
  descriptions of the callback functions.


  As of GLU version 1.2, this command is obsolete and is provided for backwards
  compatibility only. GLU version 1.2 (and later) can be distinguished during
  compilation by checking if the pre-processor symbol GLU_VERSION_1_2 is defined.

  Calls to gluBeginPolygon are mapped to gluTessBeginPolygon followed by
  gluTessBeginContour. Calls to gluEndPolygon are mapped to gluTessEndContour
  followed by gluTessEndPolygon.


  A quadrilateral with a triangular hole in it can be described	like this:

     gluTessVertex(tobj, v1, v1);
     gluTessVertex(tobj, v2, v2);
     gluTessVertex(tobj, v3, v3);
     gluTessVertex(tobj, v4, v4);
  gluNextContour(tobj, GLU_INTERIOR);
     gluTessVertex(tobj, v5, v5);
     gluTessVertex(tobj, v6, v6);
     gluTessVertex(tobj, v7, v7);

See Also

  gluNewTess, gluNextContour, gluTessCallback, gluTessVertex,
  gluTessBeginPolygon, gluTessBeginContour

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Last Edited: Fri Dec 6 11:18:03 EST 1996 by AFV
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