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# SegmentDistance.cpp

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    00001 //------------------------------------------------------------------------------
    00002 // Lamp : Open source game middleware
    00003 // Copyright (C) 2004  Junpei Ohtani ( Email : junpee@users.sourceforge.jp )
    00004 //
    00005 // This library is free software; you can redistribute it and/or
    00006 // modify it under the terms of the GNU Lesser General Public
    00007 // License as published by the Free Software Foundation; either
    00008 // version 2.1 of the License, or (at your option) any later version.
    00009 //
    00010 // This library is distributed in the hope that it will be useful,
    00011 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00012 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    00013 // Lesser General Public License for more details.
    00014 //
    00015 // You should have received a copy of the GNU Lesser General Public
    00016 // License along with this library; if not, write to the Free Software
    00017 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
    00018 //------------------------------------------------------------------------------
    00019
    00020 /** @file
    00021  * セグメント距離実装
    00022  * @author Junpee
    00023  */
    00024
    00025 #include "LampBasic.h"
    00026 #include "Geometry/Distance/SegmentDistance.h"
    00027
    00028 namespace Lamp{
    00029
    00030 //------------------------------------------------------------------------------
    00031 // 点
    00032 //------------------------------------------------------------------------------
    00033 // 点距離の二乗
    00034 float SegmentDistance::squaredDistance(
    00035     const Segment& segment, const Vector3& point){
    00036     const Vector3& direction = segment.getDirection();
    00037     Vector3 distance = point - segment.getOrigin();
    00038     float t = distance.dotProduct(direction);
    00039     // tが-だったら投影しない
    00040     if(t > 0.f){
    00041         float squaredLength = direction.getSquaredLength();
    00042         if(t >= squaredLength){
    00043             // tが方向を超えていた場合はターゲット位置からの距離
    00044             // t = 1.f;
    00045             distance -= direction;
    00046         }else{
    00047             t /= squaredLength;
    00048             distance -= t * direction;
    00049         }
    00050     }
    00051     return distance.getSquaredLength();
    00052 }
    00053 //------------------------------------------------------------------------------
    00054 // セグメント
    00055 //------------------------------------------------------------------------------
    00056 // セグメント距離の二乗
    00057 float SegmentDistance::squaredDistance(
    00058     const Segment& segment0, const Segment& segment1){
    00059     const Vector3& origin0 = segment0.getOrigin();
    00060     const Vector3& direction0 = segment0.getDirection();
    00061     const Vector3& origin1 = segment1.getOrigin();
    00062     const Vector3& direction1 = segment1.getDirection();
    00063     Vector3 direction2 = origin0 - origin1;
    00064     float dot00 = direction0.dotProduct(direction0);
    00065     float dot01 = direction0.dotProduct(direction1);
    00066     float dot11 = direction1.dotProduct(direction1);
    00067     float dot02 = direction0.dotProduct(direction2);
    00068     float dot12 = direction1.dotProduct(direction2);
    00069     float determ = dot00 * dot11 - dot01 * dot01;
    00070     float sValue, tValue, sDenom, tDenom;
    00071     sDenom = tDenom = determ;
    00072
    00073     // セグメントが平行かチェック
    00074     if(determ <= Math::epsilon){
    00075         sValue = 0.f;
    00076         sDenom = 1.f;
    00077         tValue = dot12;
    00078         tDenom = dot11;
    00079     }else{
    00080         sValue = dot01 * dot12 - dot11 * dot02;
    00081         tValue = dot00 * dot12 - dot01 * dot02;
    00082     }
    00083
    00084     // s補正
    00085     if(sValue < 0.f){
    00086         sValue = 0.f;
    00087         tValue = dot12;
    00088         tDenom = dot11;
    00089     }else if(sValue > determ){
    00090         sValue = determ;
    00091         tValue = dot01 + dot12;
    00092         tDenom = dot11;
    00093     }
    00094
    00095     // t補正
    00096     if(tValue < 0.f){
    00097         tValue = 0.f;
    00098         float tmpS = (-dot02);
    00099         if(tmpS < 0.f){
    00100             sValue = 0.f;
    00101         }else if(tmpS > dot00){
    00102             sValue = sDenom;
    00103         }else{
    00104             sValue = tmpS;
    00105             sDenom = dot00;
    00106         }
    00107     }else if(tValue > tDenom){
    00108         tValue = tDenom;
    00109         float tmpS = dot01 - dot02;
    00110         if(tmpS < 0.f){
    00111             sValue = 0.f;
    00112         }else if(tmpS > dot00){
    00113             sValue = sDenom;
    00114         }else{
    00115             sValue = tmpS;
    00116             sDenom = dot00;
    00117         }
    00118     }
    00119
    00120     float s, t;
    00121     if(Math::abs(sDenom) > Math::epsilon){ s = sValue / sDenom; }
    00122     else{ s = 0.f; }
    00123     if(Math::abs(tDenom) > Math::epsilon){ t = tValue / tDenom; }
    00124     else{ t = 0.f; }
    00125
    00126     Vector3 direction =
    00127         (origin0 + (s * direction0)) - (origin1 + (t * direction1));
    00128     return direction.getSquaredLength();
    00129 }
    00130 //------------------------------------------------------------------------------
    00131 // 球
    00132 //------------------------------------------------------------------------------
    00133 // 球距離の二乗
    00134 float SegmentDistance::squaredDistance(
    00135     const Segment& segment, const Sphere& sphere){
    00136     Assert(false);
    00137     return 0.f;
    00138 }
    00139 //------------------------------------------------------------------------------
    00140 // 三角
    00141 //------------------------------------------------------------------------------
    00142 // 三角距離の二乗
    00143 float SegmentDistance::squaredDistance(
    00144     const Segment& segment, const Triangle& triangle){
    00145     Assert(false);
    00146     return 0.f;
    00147 }
    00148 //------------------------------------------------------------------------------
    00149 } // End of namespace Lamp
    00150 //------------------------------------------------------------------------------