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Text File  |  2002-10-03  |  6.7 KB  |  133 lines
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  4. gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr((((3333GGGG))))             OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee             gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr((((3333GGGG))))
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  8. NNNNAAAAMMMMEEEE
  9.      gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr - mark the beginning of another contour
  10.  
  11.  
  12. CCCC SSSSPPPPEEEECCCCIIIIFFFFIIIICCCCAAAATTTTIIIIOOOONNNN
  13.      void gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr( GLUtesselator* _t_e_s_s,
  14.                           GLenum _t_y_p_e )
  15.  
  16.  
  17. PPPPAAAARRRRAAAAMMMMEEEETTTTEEEERRRRSSSS
  18.      _t_e_s_s  Specifies the tessellation object (created with gggglllluuuuNNNNeeeewwwwTTTTeeeessssssss).
  19.  
  20.      _t_y_p_e  Specifies the type of the contour being defined. Valid values are
  21.            GGGGLLLLUUUU____EEEEXXXXTTTTEEEERRRRIIIIOOOORRRR, GGGGLLLLUUUU____IIIINNNNTTTTEEEERRRRIIIIOOOORRRR, GGGGLLLLUUUU____UUUUNNNNKKKKNNNNOOOOWWWWNNNN, GGGGLLLLUUUU____CCCCCCCCWWWW, and GGGGLLLLUUUU____CCCCWWWW.
  22.  
  23. DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN
  24.      gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr is used in describing polygons with multiple contours.
  25.      After the first contour has been described through a series of
  26.      gggglllluuuuTTTTeeeessssssssVVVVeeeerrrrtttteeeexxxx calls, a gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr call indicates that the previous
  27.      contour is complete and that the next contour is about to begin.  Another
  28.      series of gggglllluuuuTTTTeeeessssssssVVVVeeeerrrrtttteeeexxxx calls is then used to describe the new contour.
  29.      This process can be repeated until all contours have been described.
  30.  
  31.      _t_y_p_e defines what type of contour follows.  The legal contour types are
  32.      as follows:
  33.  
  34.      GGGGLLLLUUUU____EEEEXXXXTTTTEEEERRRRIIIIOOOORRRR      An exterior contour defines an exterior boundary of the
  35.                        polygon.
  36.  
  37.      GGGGLLLLUUUU____IIIINNNNTTTTEEEERRRRIIIIOOOORRRR      An interior contour defines an interior boundary of the
  38.                        polygon (such as a hole).
  39.  
  40.      GGGGLLLLUUUU____UUUUNNNNKKKKNNNNOOOOWWWWNNNN       An unknown contour is analyzed by the library to
  41.                        determine if it is interior or exterior.
  42.  
  43.      GGGGLLLLUUUU____CCCCCCCCWWWW,
  44.  
  45.      GGGGLLLLUUUU____CCCCWWWW            The first GGGGLLLLUUUU____CCCCCCCCWWWW or GGGGLLLLUUUU____CCCCWWWW contour defined is
  46.                        considered to be exterior. All other contours are
  47.                        considered to be exterior if they are oriented in the
  48.                        same direction (clockwise or counterclockwise) as the
  49.                        first contour, and interior if they are not.
  50.  
  51.      If one contour is of type GGGGLLLLUUUU____CCCCCCCCWWWW or GGGGLLLLUUUU____CCCCWWWW, then all contours must be of
  52.      the same type (if they are not, then all GGGGLLLLUUUU____CCCCCCCCWWWW and GGGGLLLLUUUU____CCCCWWWW contours will
  53.      be changed to GGGGLLLLUUUU____UUUUNNNNKKKKNNNNOOOOWWWWNNNN).
  54.  
  55.      Note that there is no real difference between the GGGGLLLLUUUU____CCCCCCCCWWWW and GGGGLLLLUUUU____CCCCWWWW
  56.      contour types.
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  62.  
  63.                                                                         PPPPaaaaggggeeee 1111
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  70. gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr((((3333GGGG))))             OOOOppppeeeennnnGGGGLLLL RRRReeeeffffeeeerrrreeeennnncccceeee             gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr((((3333GGGG))))
  71.  
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  73.  
  74.      Before the first contour is described, gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr can be called to
  75.      define the type of the first contour.  If gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr is not called
  76.      before the first contour, then the first contour is marked GGGGLLLLUUUU____EEEEXXXXTTTTEEEERRRRIIIIOOOORRRR.
  77.  
  78.      This command is obsolete and is provided for backward compatibility only.
  79.      Calls to gggglllluuuuNNNNeeeexxxxttttCCCCoooonnnnttttoooouuuurrrr are mapped to gggglllluuuuTTTTeeeessssssssEEEEnnnnddddCCCCoooonnnnttttoooouuuurrrr followed by
  80.      gggglllluuuuTTTTeeeessssssssBBBBeeeeggggiiiinnnnCCCCoooonnnnttttoooouuuurrrr.
  81.  
  82. EEEEXXXXAAAAMMMMPPPPLLLLEEEE
  83.      A quadrilateral with a triangular hole in it can be described as follows:
  84.  
  85.  
  86.           gluBeginPolygon(tobj);
  87.              gluTessVertex(tobj, v1, v1);
  88.              gluTessVertex(tobj, v2, v2);
  89.              gluTessVertex(tobj, v3, v3);
  90.              gluTessVertex(tobj, v4, v4);
  91.           gluNextContour(tobj, GLU_INTERIOR);
  92.              gluTessVertex(tobj, v5, v5);
  93.              gluTessVertex(tobj, v6, v6);
  94.              gluTessVertex(tobj, v7, v7);
  95.           gluEndPolygon(tobj);
  96.  
  97.  
  98. SSSSEEEEEEEE AAAALLLLSSSSOOOO
  99.      gggglllluuuuBBBBeeeeggggiiiinnnnPPPPoooollllyyyyggggoooonnnn, gggglllluuuuNNNNeeeewwwwTTTTeeeessssssss, gggglllluuuuTTTTeeeessssssssCCCCaaaallllllllbbbbaaaacccckkkk, gggglllluuuuTTTTeeeessssssssVVVVeeeerrrrtttteeeexxxx,
  100.      gggglllluuuuTTTTeeeessssssssBBBBeeeeggggiiiinnnnCCCCoooonnnnttttoooouuuurrrr
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  129.                                                                         PPPPaaaaggggeeee 2222
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