sweep.h

/*
** 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(GLUtesselator *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
{
    GLUhalfEdge *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