reactos/dll/glu32/libnurbs/nurbtess/partitionX.cc

   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 ** $Date$ $Revision: 1.1 $
  35 */
  36 /*
  37 ** $Header: /cygdrive/c/RCVS/CVS/ReactOS/reactos/lib/glu32/libnurbs/nurbtess/partitionX.cc,v 1.1 2004/02/02 16:39:13 navaraf Exp $
  38 */
  39
  40 #include <stdlib.h>
  41 #include <stdio.h>
  42
  43 #include "partitionX.h"
  44
  45 #define CONCAVITY_ZERO 1.0e-6 //this number is used to test whether a vertex is concave (refelx)
  46                               //or not. The test needs to compute the area of the three adjacent
  47                               //vertices to see if the are is positive or negative.
  48
  49 Int isCuspX(directedLine *v)
  50 {
  51   //if v->prev <= v && v->next <= v
  52   //|| v->prev >= v && v->next >= v
  53   Real* T = v->head();
  54   Real* P = v->getPrev()->head();
  55   Real* N = v->getNext()->head();
  56   if(
  57      (compV2InX(T,P) != -1 &&
  58       compV2InX(T,N) != -1
  59       ) ||
  60      (compV2InX(T,P) != 1 &&
  61       compV2InX(T,N) != 1
  62       )
  63      )
  64     return 1;
  65   else
  66     return 0;
  67 }
  68
  69 Int isReflexX(directedLine* v)
  70 {
  71   Real* A = v->getPrev()->head();
  72   Real* B = v->head();
  73   Real* C = v->tail();
  74   Real Bx,By, Cx, Cy;
  75   //scale them in case they are too small
  76   Bx = 10*(B[0] - A[0]);
  77   By = 10*(B[1] - A[1]);
  78   Cx = 10*(C[0] - A[0]);
  79   Cy = 10*(C[1] - A[1]);
  80
  81   if(Bx*Cy - Cx*By < -CONCAVITY_ZERO) return 1;
  82   else return 0;
  83 }
  84
  85
  86 /*return
  87  *0: not-cusp
  88  *1: interior cusp
  89  *2: exterior cusp
  90  */
  91 Int cuspTypeX(directedLine *v)
  92 {
  93   if(! isCuspX(v)) return 0;
  94   else
  95     {
  96 //printf("isCusp,%f,%f\n", v->head()[0], v->head()[1]);
  97       if(isReflexX(v))
  98         {
  99 //        printf("isReflex\n");
 100           return 1;
 101         }
 102       else
 103         {
 104 //        printf("not isReflex\n");
 105           return 2;
 106         }
 107     }
 108 }
 109
 110 Int numInteriorCuspsX(directedLine *polygon)
 111 {
 112   directedLine *temp;
 113   int ret = 0;
 114   if(cuspTypeX(polygon) == 1)
 115     ret++;
 116   for(temp = polygon->getNext(); temp != polygon; temp = temp->getNext())
 117     if(cuspTypeX(temp) == 1)
 118       ret++;
 119   return ret;
 120 }
 121
 122
 123 void findInteriorCuspsX(directedLine *polygon, Int& ret_n_interior_cusps,
 124                         directedLine** ret_interior_cusps)
 125 {
 126   directedLine *temp;
 127   ret_n_interior_cusps = 0;
 128   if(cuspTypeX(polygon) == 1)
 129     {
 130       ret_interior_cusps[ret_n_interior_cusps++] = polygon;
 131     }
 132   for(temp = polygon->getNext(); temp != polygon; temp = temp->getNext())
 133     if(cuspTypeX(temp) == 1)
 134       {
 135         ret_interior_cusps[ret_n_interior_cusps++] = temp;
 136       }
 137 }
 138
 139 directedLine* findDiagonal_singleCuspX(directedLine* cusp)
 140 {
 141   directedLine* temp;
 142   Int is_minimal = ((compV2InX(cusp->head(), cusp->tail()) == -1)? 1:0);
 143
 144   if(is_minimal)
 145     for(temp = cusp->getNext(); temp != cusp; temp = temp->getNext())
 146       {
 147         if(compV2InX(cusp->head(), temp->head()) == 1)
 148           {
 149             return temp;
 150           }
 151       }
 152   else //is maxmal
 153     for(temp = cusp->getNext(); temp != cusp; temp = temp->getNext())
 154       {
 155         if(compV2InX(cusp->head(), temp->head()) == -1)
 156           {
 157             return temp;
 158           }
 159       }
 160   return NULL;
 161 }
 162
 163
 164