1/*
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:
9**
10** http://oss.sgi.com/projects/FreeB
11**
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.
17**
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.
23**
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.
33**
34*/
35/*
36*/
37
38#include <stdlib.h>
39#include <stdio.h>
40
41#include "partitionX.h"
42
43#define CONCAVITY_ZERO 1.0e-6 //this number is used to test whether a vertex is concave (refelx)
44                              //or not. The test needs to compute the area of the three adjacent
45                              //vertices to see if the are is positive or negative.
46
47Int isCuspX(directedLine *v)
48{
49  //if v->prev <= v && v->next <= v
50  //|| v->prev >= v && v->next >= v
51  Real* T = v->head();
52  Real* P = v->getPrev()->head();
53  Real* N = v->getNext()->head();
54  if(
55     (compV2InX(T,P) != -1 &&
56      compV2InX(T,N) != -1
57      ) ||
58     (compV2InX(T,P) != 1 &&
59      compV2InX(T,N) != 1
60      )
61     )
62    return 1;
63  else
64    return 0;
65}
66
67Int isReflexX(directedLine* v)
68{
69  Real* A = v->getPrev()->head();
70  Real* B = v->head();
71  Real* C = v->tail();
72  Real Bx,By, Cx, Cy;
73  //scale them in case they are too small
74  Bx = 10*(B[0] - A[0]);
75  By = 10*(B[1] - A[1]);
76  Cx = 10*(C[0] - A[0]);
77  Cy = 10*(C[1] - A[1]);
78
79  if(Bx*Cy - Cx*By < -CONCAVITY_ZERO) return 1;
80  else return 0;
81}
82
83
84/*return
85 *0: not-cusp
86 *1: interior cusp
87 *2: exterior cusp
88 */
89Int cuspTypeX(directedLine *v)
90{
91  if(! isCuspX(v)) return 0;
92  else
93    {
94//printf("isCusp,%f,%f\n", v->head()[0], v->head()[1]);
95      if(isReflexX(v))
96	{
97//	  printf("isReflex\n");
98	  return 1;
99	}
100      else
101	{
102//	  printf("not isReflex\n");
103	  return 2;
104	}
105    }
106}
107
108Int numInteriorCuspsX(directedLine *polygon)
109{
110  directedLine *temp;
111  int ret = 0;
112  if(cuspTypeX(polygon) == 1)
113    ret++;
114  for(temp = polygon->getNext(); temp != polygon; temp = temp->getNext())
115    if(cuspTypeX(temp) == 1)
116      ret++;
117  return ret;
118}
119
120
121void findInteriorCuspsX(directedLine *polygon, Int& ret_n_interior_cusps,
122			directedLine** ret_interior_cusps)
123{
124  directedLine *temp;
125  ret_n_interior_cusps = 0;
126  if(cuspTypeX(polygon) == 1)
127    {
128      ret_interior_cusps[ret_n_interior_cusps++] = polygon;
129    }
130  for(temp = polygon->getNext(); temp != polygon; temp = temp->getNext())
131    if(cuspTypeX(temp) == 1)
132      {
133	ret_interior_cusps[ret_n_interior_cusps++] = temp;
134      }
135}
136
137directedLine* findDiagonal_singleCuspX(directedLine* cusp)
138{
139  directedLine* temp;
140  Int is_minimal = ((compV2InX(cusp->head(), cusp->tail()) == -1)? 1:0);
141
142  if(is_minimal)
143    for(temp = cusp->getNext(); temp != cusp; temp = temp->getNext())
144      {
145	if(compV2InX(cusp->head(), temp->head()) == 1)
146	  {
147	    return temp;
148	  }
149      }
150  else //is maxmal
151    for(temp = cusp->getNext(); temp != cusp; temp = temp->getNext())
152      {
153	if(compV2InX(cusp->head(), temp->head()) == -1)
154	  {
155	    return temp;
156	  }
157      }
158  return NULL;
159}
160
161
162
163