Index for Section 3

Alphabetical listing for G

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gluNextContour()
NAME
  gluNextContour - mark the beginning of another contour

SYNOPSIS
  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 considered to be
      exterior. All other contours are considered 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 contours 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  This command is obsolete and is provided for backward compatibility only.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 follows:
  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(3), gluNewTess(3), gluTessCallback(3), gluTessVertex(3),
  gluTessBeginContour(3)

Index for Section 3

Alphabetical listing for G

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