1GLUNEXTCONTOUR(3G)                                          GLUNEXTCONTOUR(3G)
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NAME

6       gluNextContour - mark the beginning of another contour
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C SPECIFICATION

10       void gluNextContour( GLUtesselator* tess,
11                            GLenum type )
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PARAMETERS

15       tess  Specifies the tessellation object (created with gluNewTess).
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17       type  Specifies the type of the contour being defined. Valid values are
18             GLU_EXTERIOR, GLU_INTERIOR, GLU_UNKNOWN, GLU_CCW, and GLU_CW.
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DESCRIPTION

21       gluNextContour is used in describing polygons with  multiple  contours.
22       After  the  first  contour  has  been  described  through  a  series of
23       gluTessVertex calls, a gluNextContour call indicates that the  previous
24       contour  is  complete  and  that  the  next  contour is about to begin.
25       Another series of gluTessVertex calls is then used to describe the  new
26       contour.  This  process  can  be  repeated until all contours have been
27       described.
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29       type defines what type of contour follows.  The legal contour types are
30       as follows:
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32       GLU_EXTERIOR      An  exterior  contour defines an exterior boundary of
33                         the polygon.
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35       GLU_INTERIOR      An interior contour defines an interior  boundary  of
36                         the polygon (such as a hole).
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38       GLU_UNKNOWN       An  unknown  contour  is  analyzed  by the library to
39                         determine if it is interior or exterior.
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41       GLU_CCW,
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43       GLU_CW            The first GLU_CCW or GLU_CW contour defined  is  con‐
44                         sidered  to  be exterior. All other contours are con‐
45                         sidered to be exterior if they are  oriented  in  the
46                         same direction (clockwise or counterclockwise) as the
47                         first contour, and interior if they are not.
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49       If one contour is of type GLU_CCW or GLU_CW, then all contours must  be
50       of the same type (if they are not, then all GLU_CCW and GLU_CW contours
51       will be changed to GLU_UNKNOWN).
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53       Note that there is no real difference between the  GLU_CCW  and  GLU_CW
54       contour types.
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56       Before  the first contour is described, gluNextContour can be called to
57       define the type of the first contour.  If gluNextContour is not  called
58       before   the   first   contour,   then  the  first  contour  is  marked
59       GLU_EXTERIOR.
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61       This command is obsolete and is  provided  for  backward  compatibility
62       only.  Calls to gluNextContour are mapped to gluTessEndContour followed
63       by gluTessBeginContour.
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EXAMPLE

66       A quadrilateral with a triangular hole in it can be described  as  fol‐
67       lows:
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69       gluBeginPolygon(tobj);
70          gluTessVertex(tobj, v1, v1);
71          gluTessVertex(tobj, v2, v2);
72          gluTessVertex(tobj, v3, v3);
73          gluTessVertex(tobj, v4, v4); gluNextContour(tobj, GLU_INTERIOR);
74          gluTessVertex(tobj, v5, v5);
75          gluTessVertex(tobj, v6, v6);
76          gluTessVertex(tobj, v7, v7); gluEndPolygon(tobj);
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SEE ALSO

79       gluBeginPolygon(3G),        gluNewTess(3G),        gluTessCallback(3G),
80       gluTessVertex(3G), gluTessBeginContour(3G)
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85                                                            GLUNEXTCONTOUR(3G)
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