sweep.h

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/*
** Author: Eric Veach, July 1994.
**
*/

#ifndef __sweep_h_
#define __sweep_h_

#include "mesh.h"

/* __gl_computeInterior( tess ) computes the planar arrangement specified
 * by the given contours, and further subdivides this arrangement
 * into regions.  Each region is marked "inside" if it belongs
 * to the polygon, according to the rule given by tess->windingRule.
 * Each interior region is guaranteed be monotone.
 */
int __gl_computeInterior(GLUEStesselator* tess);

/* The following is here *only* for access by debugging routines */

#include "dict.h"

/* For each pair of adjacent edges crossing the sweep line, there is
 * an ActiveRegion to represent the region between them.  The active
 * regions are kept in sorted order in a dynamic dictionary.  As the
 * sweep line crosses each vertex, we update the affected regions.
 */

struct ActiveRegion
{
   GLUEShalfEdge*  eUp;           /* upper edge, directed right to left      */
   DictNode*     nodeUp;        /* dictionary node corresponding to eUp    */
   int           windingNumber; /* used to determine which regions are
                                 * inside the polygon                      */
   GLboolean     inside;        /* is this region inside the polygon?      */
   GLboolean     sentinel;      /* marks fake edges at t = +/-infinity     */
   GLboolean     dirty;         /* marks regions where the upper or lower
                                 * edge has changed, but we haven't checked
                                 * whether they intersect yet              */
   GLboolean     fixUpperEdge;  /* marks temporary edges introduced when
                                 * we process a "right vertex" (one without
                                 * any edges leaving to the right)         */
};

#define RegionBelow(r) ((ActiveRegion*)dictKey(dictPred((r)->nodeUp)))
#define RegionAbove(r) ((ActiveRegion*)dictKey(dictSucc((r)->nodeUp)))

#endif /* __sweep_h_ */