Public API Reference

csgeom/plane2.h

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/*
    Copyright (C) 1998-2000 by Jorrit Tyberghein
    Largely rewritten by Ivan Avramovic <[email protected]>

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/

#ifndef __CS_PLANE2_H__
#define __CS_PLANE2_H__


#include "csextern.h"

#include "csgeom/segment.h"
#include "csgeom/vector2.h"

enum 
{
  CS_POLY_IN = 1,
  CS_POLY_ON = 0,
  CS_POLY_OUT = -1
};

class csPlane2
{
public:
  csVector2 norm;

  float CC;

  csPlane2 () : norm (0,1), CC (0) {}

  csPlane2 (const csVector2& plane_norm, float c=0)
        : norm (plane_norm), CC (c) {}

  csPlane2 (float a, float b, float c=0) : norm (a,b), CC (c) {}

  inline void Set (const csVector2& v1, const csVector2& v2)
  {
    norm.x = v2.y-v1.y;
    norm.y = -(v2.x-v1.x);
    CC = - (v2 * norm);
  }

  inline void Set (const csSegment2& s)
  {
    Set (s.Start (), s.End ());
  }

  csPlane2 (const csVector2& v1, const csVector2& v2)
  {
    Set (v1, v2);
  }

  csPlane2 (const csSegment2& s)
  {
    Set (s);
  }

  inline csVector2& Normal () { return norm; }

  inline csVector2 GetNormal () const { return norm; }

  inline float A () const { return norm.x; }
  inline float B () const { return norm.y; }
  inline float C () const { return CC; }

  inline float& A () { return norm.x; }
  inline float& B () { return norm.y; }
  inline float& C () { return CC; }

  inline void Set (float a, float b, float c)
  { norm.x = a; norm.y = b; CC = c; }

  inline float Classify (const csVector2& pt) const { return norm*pt+CC; }

  static float Classify (float A, float B, float C,
                         const csVector2& pt)
  { return A*pt.x + B*pt.y + C; }

  inline float Distance (const csVector2& pt) const
  { return ABS (Classify (pt)); }

  inline float SquaredDistance (const csVector2& pt) const
  {
    return Classify (pt) / norm.SquaredNorm ();
  }

  inline void Invert () { norm = -norm;  CC = -CC; }

  inline void Normalize ()
  {
    float f = norm.Norm ();
    if (f) { norm /= f;  CC /= f; }
  }
};

#endif // __CS_PLANE2_H__

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