2 ** License Applicability. Except to the extent portions of this file are
3 ** made subject to an alternative license as permitted in the SGI Free
4 ** Software License B, Version 1.1 (the "License"), the contents of this
5 ** file are subject only to the provisions of the License. You may not use
6 ** this file except in compliance with the License. You may obtain a copy
7 ** of the License at Silicon Graphics, Inc., attn: Legal Services, 1600
8 ** Amphitheatre Parkway, Mountain View, CA 94043-1351, or at:
10 ** http://oss.sgi.com/projects/FreeB
12 ** Note that, as provided in the License, the Software is distributed on an
13 ** "AS IS" basis, with ALL EXPRESS AND IMPLIED WARRANTIES AND CONDITIONS
14 ** DISCLAIMED, INCLUDING, WITHOUT LIMITATION, ANY IMPLIED WARRANTIES AND
15 ** CONDITIONS OF MERCHANTABILITY, SATISFACTORY QUALITY, FITNESS FOR A
16 ** PARTICULAR PURPOSE, AND NON-INFRINGEMENT.
18 ** Original Code. The Original Code is: OpenGL Sample Implementation,
19 ** Version 1.2.1, released January 26, 2000, developed by Silicon Graphics,
20 ** Inc. The Original Code is Copyright (c) 1991-2000 Silicon Graphics, Inc.
21 ** Copyright in any portions created by third parties is as indicated
22 ** elsewhere herein. All Rights Reserved.
24 ** Additional Notice Provisions: The application programming interfaces
25 ** established by SGI in conjunction with the Original Code are The
26 ** OpenGL(R) Graphics System: A Specification (Version 1.2.1), released
27 ** April 1, 1999; The OpenGL(R) Graphics System Utility Library (Version
28 ** 1.3), released November 4, 1998; and OpenGL(R) Graphics with the X
29 ** Window System(R) (Version 1.3), released October 19, 1998. This software
30 ** was created using the OpenGL(R) version 1.2.1 Sample Implementation
31 ** published by SGI, but has not been independently verified as being
32 ** compliant with the OpenGL(R) version 1.2.1 Specification.
34 ** $Date: 2001/03/17 00:25:41 $ $Revision: 1.1 $
38 *partition a polygon into a Y-monotone polygon:
39 * A polygon is Y-monotone if the boundary can be split into two polygon chains
40 *A and B such that each chain is Y-monotonic that is the intersection of any
41 *horizontal line intersects each chain has at most one connected componenets
42 * (empty, single point or a single line).
44 * A vertex is a cusp if both its ajacent vertices are either at or above v,
45 *or both at or below v. In addition, at least one of the ajacent verteces is
46 *strictly below or above v.
47 * A vertex is a relex vertex if the internals angle is strictly greater than
48 *180. In other words, if the the signed area is negative:
49 *(x1, y1), (x2, y2), (x3, y3) are the three vertices along a polygon, the
50 *order is such that left hand side is inside the polygon. Then (x2,y2) is
52 * (x2-x1, y2-y1) cross (x3-x1, y3-y1) <0.
53 *A vertex is an interior cusp if it is a cusp and a reflex.
54 *A vertex is an exterior cusp if it is a cusp but not a reflex.
56 * $Header: /home/krh/git/sync/mesa-cvs-repo/Mesa/src/glu/sgi/libnurbs/nurbtess/partitionY.h,v 1.1 2001/03/17 00:25:41 brianp Exp $
62 #include "directedLine.h"
64 /*whether an edge is below a vertex*/
65 Int
isBelow(directedLine
*v
, directedLine
*e
);
67 /*whether an edge is above a vertex*/
68 Int
isAbove(directedLine
*v
, directedLine
*e
);
74 Int
cuspType(directedLine
*v
);
76 /*used in trapezoidalization*/
77 typedef struct sweepRange
{
79 Int leftType
; /*either a vertex (leftType=0) or an edge (leftType =1) */
81 Int rightType
; /*either a vertex (rightType=0) or an edge (rightType =1) */
84 sweepRange
* sweepRangeMake(directedLine
* left
, Int leftType
,
85 directedLine
* right
, Int rightType
);
87 void sweepRangeDelete(sweepRange
* range
);
88 Int
sweepRangeEqual(sweepRange
* sr1
, sweepRange
* sr2
);
90 /*given a set of simple polygons where the interior
91 *is decided by left-hand principle,
92 *return a range (sight) for each vertex. This is called
95 void sweepY(Int nVertices
, directedLine
**sortedVerteces
, sweepRange
** ret_ranges
);
98 directedLine
* partitionY(directedLine
*polygons
, sampledLine
**retSampledLines
);
100 void findDiagonals(Int total_num_edges
, directedLine
** sortedVertices
, sweepRange
** ranges
, Int
& num_diagonals
, directedLine
** diagonal_vertices
);
102 directedLine
** DBGfindDiagonals(directedLine
*polygons
, Int
& num_diagonals
);