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/*
* SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
* Copyright (C) 1991-2000 Silicon Graphics, Inc. All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice including the dates of first publication and
* either this permission notice or a reference to
* http://oss.sgi.com/projects/FreeB/
* shall be included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
* OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* SILICON GRAPHICS, INC. BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF
* OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*
* Except as contained in this notice, the name of Silicon Graphics, Inc.
* shall not be used in advertising or otherwise to promote the sale, use or
* other dealings in this Software without prior written authorization from
* Silicon Graphics, Inc.
*/
/*
*partitionY.h:
*partition a polygon into a Y-monotone polygon:
* A polygon is Y-monotone if the boundary can be split into two polygon chains
*A and B such that each chain is Y-monotonic that is the intersection of any
*horizontal line intersects each chain has at most one connected componenets
* (empty, single point or a single line).
*
* A vertex is a cusp if both its ajacent vertices are either at or above v,
*or both at or below v. In addition, at least one of the ajacent verteces is
*strictly below or above v.
* A vertex is a relex vertex if the internals angle is strictly greater than
*180. In other words, if the signed area is negative:
*(x1, y1), (x2, y2), (x3, y3) are the three vertices along a polygon, the
*order is such that left hand side is inside the polygon. Then (x2,y2) is
*reflex if:
* (x2-x1, y2-y1) cross (x3-x1, y3-y1) <0.
*A vertex is an interior cusp if it is a cusp and a reflex.
*A vertex is an exterior cusp if it is a cusp but not a reflex.
*
*/
#ifndef _PARTITIONY_H
#define _PARTITIONY_H
#include "directedLine.h"
/*whether an edge is below a vertex*/
Int isBelow(directedLine *v, directedLine *e);
/*whether an edge is above a vertex*/
Int isAbove(directedLine *v, directedLine *e);
/*not-cusp,
*inerior cusp
*exterior cusp
*/
Int cuspType(directedLine *v);
/*used in trapezoidalization*/
typedef struct sweepRange{
directedLine *left;
Int leftType; /*either a vertex (leftType=0) or an edge (leftType =1) */
directedLine *right;
Int rightType; /*either a vertex (rightType=0) or an edge (rightType =1) */
} sweepRange;
sweepRange* sweepRangeMake(directedLine* left, Int leftType,
directedLine* right, Int rightType);
void sweepRangeDelete(sweepRange* range);
Int sweepRangeEqual(sweepRange* sr1, sweepRange* sr2);
/*given a set of simple polygons where the interior
*is decided by left-hand principle,
*return a range (sight) for each vertex. This is called
*Trapezoidalization.
*/
void sweepY(Int nVertices, directedLine **sortedVerteces, sweepRange** ret_ranges);
directedLine* partitionY(directedLine *polygons, sampledLine **retSampledLines);
void findDiagonals(Int total_num_edges, directedLine** sortedVertices, sweepRange** ranges, Int& num_diagonals, directedLine** diagonal_vertices);
directedLine** DBGfindDiagonals(directedLine *polygons, Int& num_diagonals);
#endif
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