gluNextContour

GLUNEXTCONTOUR(3G)					   GLUNEXTCONTOUR(3G)



NAME
       gluNextContour - mark the beginning of another contour


C SPECIFICATION
       void gluNextContour( GLUtesselator* tess,
			    GLenum type )


PARAMETERS
       tess  Specifies the tessellation object (created with gluNewTess).

       type  Specifies	the  type  of the contour being defined. Valid values
	     are  GLU_EXTERIOR,	 GLU_INTERIOR,	GLU_UNKNOWN,   GLU_CCW,	  and
	     GLU_CW.

DESCRIPTION
       gluNextContour  is used in describing polygons with multiple contours.
       After the first	contour	 has  been  described  through	a  series  of
       gluTessVertex calls, a gluNextContour call indicates that the previous
       contour is complete and that the	 next  contour	is  about  to  begin.
       Another series of gluTessVertex calls is then used to describe the new
       contour. This process can be repeated until  all	 contours  have	 been
       described.

       type  defines  what  type of contour follows.  The legal contour types
       are as follows:

       GLU_EXTERIOR	 An exterior contour defines an exterior boundary  of
			 the polygon.

       GLU_INTERIOR	 An  interior contour defines an interior boundary of
			 the polygon (such as a hole).

       GLU_UNKNOWN	 An unknown contour is analyzed	 by  the  library  to
			 determine if it is interior or exterior.

       GLU_CCW,

       GLU_CW		 The  first GLU_CCW or GLU_CW contour defined is con-
			 sidered to be exterior. All other contours are	 con-
			 sidered  to  be exterior if they are oriented in the
			 same direction (clockwise  or	counterclockwise)  as
			 the first contour, and interior if they are not.

       If one contour is of type GLU_CCW or GLU_CW, then all contours must be
       of the same type (if they are not, then all GLU_CCW  and	 GLU_CW	 con-
       tours will be changed to GLU_UNKNOWN).

       Note  that  there is no real difference between the GLU_CCW and GLU_CW
       contour types.

       Before the first contour is described, gluNextContour can be called to
       define the type of the first contour.  If gluNextContour is not called
       before  the  first  contour,  then  the	first	contour	  is   marked
       GLU_EXTERIOR.

       This  command  is  obsolete and is provided for backward compatibility
       only. Calls to gluNextContour are mapped to gluTessEndContour followed
       by gluTessBeginContour.

EXAMPLE
       A  quadrilateral with a triangular hole in it can be described as fol-
       lows:

       gluBeginPolygon(tobj);
	  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); gluEndPolygon(tobj);

SEE ALSO
       gluBeginPolygon(3G),	  gluNewTess(3G),	 gluTessCallback(3G),
       gluTessVertex(3G), gluTessBeginContour(3G)




							   GLUNEXTCONTOUR(3G)