source: GTP/trunk/Lib/Vis/Preprocessing/src/Plane3.h @ 860

#ifndef _Plane3_H__
#define _Plane3_H__

#include "Vector3.h"

namespace GtpVisibilityPreprocessor {

  
/** 3D Plane */
class Plane3 {
public:

  Vector3 mNormal;
  float mD;
  
  Plane3() {}
  
  Plane3(const Vector3 &a,
                 const Vector3 &b,
                 const Vector3 &c
         ) {
    Vector3 v1=a-b, v2=c-b;
    mNormal = Normalize(CrossProd(v2,v1));
    mD = -DotProd(b, mNormal);
  }

  Plane3(const Vector3 &normal,
                 const Vector3 &point
                 ):mNormal(normal)
  {
    mD = -DotProd(normal, point);
  }

  void ReverseOrientation()
  {
          mNormal *= -1;
          mD *= -1;
  }

  float Distance(const Vector3 &v) const {
    return DotProd(v, mNormal) + mD;
  }

  enum {BACK_SIDE = -1, INTERSECTS = 0, FRONT_SIDE = 1};
                 
                
  /** Returns 1 if v is on front side, -1 if on back side, 0 if on plane.
  */
  int Side(const Vector3 &v, const float threshold = 1e-6) const;

  /** Finds intersection of line segment between points a and b with plane.
          @param a start point
          @param b end point
          @param t if not NULL, returns parameter value of intersections
          @param coplanar if not NULL, returns true if plane and line segments are coplanar.
  */
  Vector3 FindIntersection(const Vector3 &a,
                                                   const Vector3 &b,
                                                   float *t = NULL,
                                                   bool *coplanar = NULL) const;
  
  /** Finds value of intersection parameter t on line segment from a to b.
      @returns 0 if coplanar, else parameter t
  */
  float FindT(const Vector3 &a, const Vector3 &b) const;

  friend bool
  PlaneIntersection(const Plane3 &a, const Plane3 &b, const Plane3 &c, Vector3 &result);
  
  friend ostream &operator<<(ostream &s, const Plane3 p) {
    s<<p.mNormal<<" "<<p.mD;
    return s;
  }

  
};
  

}

#endif