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104 lines
4.3 KiB
C
104 lines
4.3 KiB
C
/*
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** License Applicability. Except to the extent portions of this file are
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** made subject to an alternative license as permitted in the SGI Free
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** Software License B, Version 1.1 (the "License"), the contents of this
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** file are subject only to the provisions of the License. You may not use
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** this file except in compliance with the License. You may obtain a copy
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** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
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** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
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**
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** http://oss.sgi.com/projects/FreeB
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**
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** Note that, as provided in the License, the Software is distributed on an
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** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
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** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
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** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
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** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
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**
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** Original Code. The Original Code is: OpenGL Sample Implementation,
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** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
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** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
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** Copyright in any portions created by third parties is as indicated
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** elsewhere herein. All Rights Reserved.
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**
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** Additional Notice Provisions: The application programming interfaces
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** established by SGI in conjunction with the Original Code are The
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** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
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** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
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** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
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** Window System(R) (Version 1.3), released October 19, 1998. This software
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** was created using the OpenGL(R) version 1.2.1 Sample Implementation
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** published by SGI, but has not been independently verified as being
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** compliant with the OpenGL(R) version 1.2.1 Specification.
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**
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** $Date$ $Revision: 1.1 $
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*/
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/*
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*partitionY.h:
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*partition a polygon into a Y-monotone polygon:
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* A polygon is Y-monotone if the boundary can be split into two polygon chains
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*A and B such that each chain is Y-monotonic that is the intersection of any
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*horizontal line intersects each chain has at most one connected componenets
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* (empty, single point or a single line).
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*
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* A vertex is a cusp if both its ajacent vertices are either at or above v,
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*or both at or below v. In addition, at least one of the ajacent verteces is
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*strictly below or above v.
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* A vertex is a relex vertex if the internals angle is strictly greater than
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*180. In other words, if the the signed area is negative:
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*(x1, y1), (x2, y2), (x3, y3) are the three vertices along a polygon, the
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*order is such that left hand side is inside the polygon. Then (x2,y2) is
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*reflex if:
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* (x2-x1, y2-y1) cross (x3-x1, y3-y1) <0.
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*A vertex is an interior cusp if it is a cusp and a reflex.
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*A vertex is an exterior cusp if it is a cusp but not a reflex.
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*
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* $Header: /cygdrive/c/RCVS/CVS/ReactOS/reactos/lib/glu32/libnurbs/nurbtess/partitionY.h,v 1.1 2004/02/02 16:39:13 navaraf Exp $
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*/
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#ifndef _PARTITIONY_H
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#define _PARTITIONY_H
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#include "directedLine.h"
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/*whether an edge is below a vertex*/
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Int isBelow(directedLine *v, directedLine *e);
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/*whether an edge is above a vertex*/
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Int isAbove(directedLine *v, directedLine *e);
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/*not-cusp,
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*inerior cusp
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*exterior cusp
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*/
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Int cuspType(directedLine *v);
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/*used in trapezoidalization*/
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typedef struct sweepRange{
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directedLine *left;
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Int leftType; /*either a vertex (leftType=0) or an edge (leftType =1) */
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directedLine *right;
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Int rightType; /*either a vertex (rightType=0) or an edge (rightType =1) */
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} sweepRange;
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sweepRange* sweepRangeMake(directedLine* left, Int leftType,
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directedLine* right, Int rightType);
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void sweepRangeDelete(sweepRange* range);
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Int sweepRangeEqual(sweepRange* sr1, sweepRange* sr2);
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/*given a set of simple polygons where the interior
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*is decided by left-hand principle,
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*return a range (sight) for each vertex. This is called
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*Trapezoidalization.
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*/
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void sweepY(Int nVertices, directedLine **sortedVerteces, sweepRange** ret_ranges);
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directedLine* partitionY(directedLine *polygons, sampledLine **retSampledLines);
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void findDiagonals(Int total_num_edges, directedLine** sortedVertices, sweepRange** ranges, Int& num_diagonals, directedLine** diagonal_vertices);
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directedLine** DBGfindDiagonals(directedLine *polygons, Int& num_diagonals);
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#endif
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