1 | /************************************************************** ggt-head beg |
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2 | * |
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3 | * GGT: Generic Graphics Toolkit |
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4 | * |
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5 | * Original Authors: |
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6 | * Allen Bierbaum |
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7 | * |
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8 | * ----------------------------------------------------------------- |
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9 | * File: LineSegOps.h,v |
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10 | * Date modified: 2004/09/16 21:21:09 |
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11 | * Version: 1.8 |
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12 | * ----------------------------------------------------------------- |
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13 | * |
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14 | *********************************************************** ggt-head end */ |
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15 | /*************************************************************** ggt-cpr beg |
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16 | * |
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17 | * GGT: The Generic Graphics Toolkit |
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18 | * Copyright (C) 2001,2002 Allen Bierbaum |
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19 | * |
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20 | * This library is free software; you can redistribute it and/or |
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21 | * modify it under the terms of the GNU Lesser General Public |
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22 | * License as published by the Free Software Foundation; either |
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23 | * version 2.1 of the License, or (at your option) any later version. |
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24 | * |
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25 | * This library is distributed in the hope that it will be useful, |
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26 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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27 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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28 | * Lesser General Public License for more details. |
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29 | * |
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30 | * You should have received a copy of the GNU Lesser General Public |
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31 | * License along with this library; if not, write to the Free Software |
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32 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
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33 | * |
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34 | ************************************************************ ggt-cpr end */ |
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35 | #ifndef _GMTL_LINESEGOPS_H_ |
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36 | #define _GMTL_LINESEGOPS_H_ |
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37 | |
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38 | #include <gmtl/LineSeg.h> |
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39 | #include <gmtl/RayOps.h> |
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40 | |
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41 | namespace gmtl { |
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42 | |
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43 | /** |
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44 | * Finds the closest point on the line segment to a given point. |
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45 | * |
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46 | * @param lineseg the line segment to test |
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47 | * @param pt the point which to test against lineseg |
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48 | * |
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49 | * @return the point on the line segment closest to pt |
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50 | */ |
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51 | template< class DATA_TYPE > |
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52 | Point<DATA_TYPE, 3> findNearestPt( const LineSeg<DATA_TYPE>& lineseg, |
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53 | const Point<DATA_TYPE, 3>& pt ) |
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54 | { |
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55 | // result = origin + dir * dot((pt-origin), dir) |
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56 | return ( lineseg.mOrigin + lineseg.mDir * |
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57 | dot(pt - lineseg.mOrigin, lineseg.mDir) ); |
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58 | } |
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59 | |
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60 | /** |
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61 | * Computes the shortest distance from the line segment to the given point. |
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62 | * |
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63 | * @param lineseg the line segment to test |
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64 | * @param pt the point which to test against lineseg |
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65 | * |
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66 | * @return the shortest distance from pt to lineseg |
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67 | */ |
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68 | template< class DATA_TYPE > |
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69 | inline DATA_TYPE distance( const LineSeg<DATA_TYPE>& lineseg, |
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70 | const Point<DATA_TYPE, 3>& pt ) |
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71 | { |
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72 | return gmtl::length(gmtl::Vec<DATA_TYPE, 3>(pt - findNearestPt(lineseg, pt))); |
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73 | } |
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74 | |
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75 | /** |
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76 | * Computes the shortest distance from the line segment to the given point. |
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77 | * |
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78 | * @param lineseg the line segment to test |
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79 | * @param pt the point which to test against lineseg |
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80 | * |
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81 | * @return the squared shortest distance from pt to lineseg (value is squared, this func is slightly faster since it doesn't involve a sqrt) |
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82 | */ |
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83 | template< class DATA_TYPE > |
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84 | inline DATA_TYPE distanceSquared( const LineSeg<DATA_TYPE>& lineseg, |
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85 | const Point<DATA_TYPE, 3>& pt ) |
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86 | { |
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87 | return gmtl::lengthSquared(gmtl::Vec<DATA_TYPE, 3>(pt - findNearestPt(lineseg, pt))); |
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88 | } |
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89 | |
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90 | |
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91 | } // namespace gmtl |
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92 | #endif |
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