gluTessVertex.3gl (GLU version 1.2 and later)

Name

  gluTessVertex	- specify a vertex on a	polygon

C Specification

  void gluTessVertex( GLUtesselator *tess,
		      GLdouble coords[3],
		      void *data )

Parameters

  tess	  Specifies the	tessellation object (created with gluNewTess).

  coords  Specifies the	location of the	vertex.

  data	  Specifies an opaque pointer passed back to the user with the vertex
	  callback (as specified by gluTessCallback).

Description

  gluTessVertex	describes a vertex on a	polygon	that the user is defining.
  Successive gluTessVertex calls describe a closed contour.  For example, if
  the user wants to describe a quadrilateral, then gluTessVertex should	be
  called four times.  gluTessVertex can	only be	called between
  gluTessBeginContour and gluTessEndContour.

  data normally	points to a structure containing the vertex location, as well
  as other per-vertex attributes such as color and normal.  This pointer is
  passed back to the user through the GLU_TESS_VERTEX or GLU_TESS_VERTEX_DATA
  callback after tessellation (see the gluTessCallback reference page).

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

  gluTessBeginPolygon, gluNewTess, gluTessBeginContour,	gluTessCallback,
  gluTessProperty, gluTessNormal, gluTessEndPolygon

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Last Edited: Fri, May 26, 1995

AFV