plane2.h Source File

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 #define CS_POLY_IN 1
00024 #define CS_POLY_ON 0
00025 #define CS_POLY_OUT -1
00026 
00027 #include "csgeom/vector2.h"
00028 #include "csgeom/segment.h"
00029 
00030 class csPoly2D;
00031 
00037 class csPlane2
00038 {
00039 public:
00041   csVector2 norm;
00042 
00044   float CC;
00045 
00047   csPlane2 () : norm (0,1), CC (0) {}
00048 
00050   csPlane2 (const csVector2& plane_norm, float c=0) : norm (plane_norm), CC (c) {}
00051 
00053   csPlane2 (float a, float b, float c=0) : norm (a,b), CC (c) {}
00054 
00056   inline void Set (const csVector2& v1, const csVector2& v2)
00057   {
00058     norm.x = v2.y-v1.y;
00059     norm.y = -(v2.x-v1.x);
00060     CC = - (v2 * norm);
00061   }
00062 
00064   inline void Set (const csSegment2& s)
00065   {
00066     Set (s.Start (), s.End ());
00067   }
00068 
00070   csPlane2 (const csVector2& v1, const csVector2& v2)
00071   {
00072     Set (v1, v2);
00073   }
00074 
00076   csPlane2 (const csSegment2& s)
00077   {
00078     Set (s);
00079   }
00080 
00082   inline csVector2& Normal () { return norm; }
00083 
00085   inline csVector2 GetNormal () const { return norm; }
00086 
00088   inline float A () const { return norm.x; }
00090   inline float B () const { return norm.y; }
00092   inline float C () const { return CC; }
00093 
00095   inline float& A () { return norm.x; }
00097   inline float& B () { return norm.y; }
00099   inline float& C () { return CC; }
00100 
00102   inline void Set (float a, float b, float c)
00103   { norm.x = a; norm.y = b; CC = c; }
00104 
00106   inline float Classify (const csVector2& pt) const { return norm*pt+CC; }
00107 
00109   static float Classify (float A, float B, float C,
00110                          const csVector2& pt)
00111   { return A*pt.x + B*pt.y + C; }
00112 
00118   inline float Distance (const csVector2& pt) const
00119   { return ABS (Classify (pt)); }
00120 
00127   inline float SquaredDistance (const csVector2& pt) const
00128   {
00129     return Classify (pt) / norm.SquaredNorm ();
00130   }
00131 
00133   void Invert () { norm = -norm;  CC = -CC; }
00134 
00136   void Normalize ()
00137   {
00138     float f = norm.Norm ();
00139     if (f) { norm /= f;  CC /= f; }
00140   }
00141 };
00142 
00143 #endif // __CS_PLANE2_H__