src/glu/sgi/libtess/sweep.h

   1 /*
   2  * SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
   3  * Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
   4  *
   5  * Permission is hereby granted, free of charge, to any person obtaining a
   6  * copy of this software and associated documentation files (the "Software"),
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   9  * and/or sell copies of the Software, and to permit persons to whom the
  10  * Software is furnished to do so, subject to the following conditions:
  11  *
  12  * The above copyright notice including the dates of first publication and
  13  * either this permission notice or a reference to
  14  * http://oss.sgi.com/projects/FreeB/
  15  * shall be included in all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  18  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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  20  * SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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  22  * OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  23  * SOFTWARE.
  24  *
  25  * Except as contained in this notice, the name of Silicon Graphics, Inc.
  26  * shall not be used in advertising or otherwise to promote the sale, use or
  27  * other dealings in this Software without prior written authorization from
  28  * Silicon Graphics, Inc.
  29  */
  30 /*
  31 ** Author: Eric Veach, July 1994.
  32 **
  33 */
  34
  35 #ifndef __sweep_h_
  36 #define __sweep_h_
  37
  38 #include "mesh.h"
  39
  40 /* __gl_computeInterior( tess ) computes the planar arrangement specified
  41  * by the given contours, and further subdivides this arrangement
  42  * into regions.  Each region is marked "inside" if it belongs
  43  * to the polygon, according to the rule given by tess->windingRule.
  44  * Each interior region is guaranteed be monotone.
  45  */
  46 int __gl_computeInterior( GLUtesselator *tess );
  47
  48
  49 /* The following is here *only* for access by debugging routines */
  50
  51 #include "dict.h"
  52
  53 /* For each pair of adjacent edges crossing the sweep line, there is
  54  * an ActiveRegion to represent the region between them.  The active
  55  * regions are kept in sorted order in a dynamic dictionary.  As the
  56  * sweep line crosses each vertex, we update the affected regions.
  57  */
  58
  59 struct ActiveRegion {
  60   GLUhalfEdge   *eUp;           /* upper edge, directed right to left */
  61   DictNode      *nodeUp;        /* dictionary node corresponding to eUp */
  62   int           windingNumber;  /* used to determine which regions are
  63                                  * inside the polygon */
  64   GLboolean     inside;         /* is this region inside the polygon? */
  65   GLboolean     sentinel;       /* marks fake edges at t = +/-infinity */
  66   GLboolean     dirty;          /* marks regions where the upper or lower
  67                                  * edge has changed, but we haven't checked
  68                                  * whether they intersect yet */
  69   GLboolean     fixUpperEdge;   /* marks temporary edges introduced when
  70                                  * we process a "right vertex" (one without
  71                                  * any edges leaving to the right) */
  72 };
  73
  74 #define RegionBelow(r)  ((ActiveRegion *) dictKey(dictPred((r)->nodeUp)))
  75 #define RegionAbove(r)  ((ActiveRegion *) dictKey(dictSucc((r)->nodeUp)))
  76
  77 #endif