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# csgeom/plane2.h

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    00001 /*
    00002     Copyright (C) 1998-2000 by Jorrit Tyberghein
    00003     Largely rewritten by Ivan Avramovic <ivan@avramovic.com>
    00004
    00005     This library is free software; you can redistribute it and/or
    00006     modify it under the terms of the GNU Library General Public
    00007     License as published by the Free Software Foundation; either
    00008     version 2 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     Library General Public License for more details.
    00014
    00015     You should have received a copy of the GNU Library General Public
    00016     License along with this library; if not, write to the Free
    00017     Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
    00018 */
    00019
    00020 #ifndef __CS_PLANE2_H__
    00021 #define __CS_PLANE2_H__
    00022
    00023
    00024 #include "csextern.h"
    00025
    00026 #include "csgeom/segment.h"
    00027 #include "csgeom/vector2.h"
    00028
    00036 enum
    00037 {
    00038   CS_POLY_IN = 1,
    00039   CS_POLY_ON = 0,
    00040   CS_POLY_OUT = -1
    00041 };
    00042
    00048 class csPlane2
    00049 {
    00050 public:
    00052   csVector2 norm;
    00053
    00055   float CC;
    00056
    00058   csPlane2 () : norm (0,1), CC (0) {}
    00059
    00061   csPlane2 (const csVector2& plane_norm, float c=0)
    00062         : norm (plane_norm), CC (c) {}
    00063
    00065   csPlane2 (float a, float b, float c=0) : norm (a,b), CC (c) {}
    00066
    00068   inline void Set (const csVector2& v1, const csVector2& v2)
    00069   {
    00070     norm.x = v2.y-v1.y;
    00071     norm.y = -(v2.x-v1.x);
    00072     CC = - (v2 * norm);
    00073   }
    00074
    00076   inline void Set (const csSegment2& s)
    00077   {
    00078     Set (s.Start (), s.End ());
    00079   }
    00080
    00082   csPlane2 (const csVector2& v1, const csVector2& v2)
    00083   {
    00084     Set (v1, v2);
    00085   }
    00086
    00088   csPlane2 (const csSegment2& s)
    00089   {
    00090     Set (s);
    00091   }
    00092
    00094   inline csVector2& Normal () { return norm; }
    00095
    00097   inline csVector2 GetNormal () const { return norm; }
    00098
    00100   inline float A () const { return norm.x; }
    00102   inline float B () const { return norm.y; }
    00104   inline float C () const { return CC; }
    00105
    00107   inline float& A () { return norm.x; }
    00109   inline float& B () { return norm.y; }
    00111   inline float& C () { return CC; }
    00112
    00114   inline void Set (float a, float b, float c)
    00115   { norm.x = a; norm.y = b; CC = c; }
    00116
    00118   inline float Classify (const csVector2& pt) const { return norm*pt+CC; }
    00119
    00121   static float Classify (float A, float B, float C,
    00122                          const csVector2& pt)
    00123   { return A*pt.x + B*pt.y + C; }
    00124
    00130   inline float Distance (const csVector2& pt) const
    00131   { return ABS (Classify (pt)); }
    00132
    00139   inline float SquaredDistance (const csVector2& pt) const
    00140   {
    00141     return Classify (pt) / norm.SquaredNorm ();
    00142   }
    00143
    00145   inline void Invert () { norm = -norm;  CC = -CC; }
    00146
    00148   inline void Normalize ()
    00149   {
    00150     float f = norm.Norm ();
    00151     if (f) { norm /= f;  CC /= f; }
    00152   }
    00153 };
    00154
    00157 #endif // __CS_PLANE2_H__