include/geometry/plane.h

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/*********************************************************************
** Copyright (c) 1998 MaK Technologies, Inc.
** All rights reserved.
*********************************************************************/
/*********************************************************************
** $RCSfile: plane.h,v $ $Revision: 1.12 $ $State: Exp $
*********************************************************************/

#ifndef plane_H_
#define plane_H_

// \file plane.h
// \brief Contains the DtPlane class declaration.

#include <vlutil/vlMachineTypes.h>
#include "geometry/geometryDefines.h"

// forward declarations
class DtPoint;
class DtVector;
class DtChord;

//
// DtPlane represents a plane in 3-space.
class DT_DLL_geometry DtPlane
{
public:

   // default constructor (returns the xy-plane)
   DtPlane();

   // Define the plane passing through points v0, v1, and v2.
   // the three points v0, v1, and v2, are not collinear and not coincident.
   // The vertices v0, v1, and v2 appear in counterclockwise
   // order when viewing the plane from outside to inside in
   // a right-handed Cartesian coordinate system.
   DtPlane(const DtPoint& v0, const DtPoint& v1, const DtPoint& v2);

   // Plane defined by a location and normal direction vector.
   // \note The second parameter is passed by value so that the copy can be used
   // internally to the function, for performance reasons.
   DtPlane(const DtVector& point, DtVector normal);

   // define a plane by specifying the coefficients for the plane equation:
   // Ax + By + Cz + D = 0
   DtPlane(double a, double b, double c, double d);

   // Special version of the constructor that specifies the plane's coefficients, 
   // in that is assumes they are correct as specified.  
   // \note This version does \b not test them for correctness!
   DtPlane(bool ignored, double a, double b, double c, double d);

   // copy constructor
   DtPlane(const DtPlane& orig);

   // destructor
   virtual ~DtPlane();

   // assignment operator
   DtPlane& operator=(const DtPlane& orig);

   // Coefficients of the plane equation Ax + By + Cz + D = 0.
   virtual double a() const;
   virtual double b() const;
   virtual double c() const;
   virtual double d() const;

   // compute the vector normal to the plane.
   virtual const DtVector normal() const;

   // determine if chord intersects the plane; time specifies the
   // parametric value along the chord. 
   virtual bool intersects(const DtChord& chord, double& time) const;

   // print the contents of the object
   virtual void dump() const;

   // compute the distance of a point p to the plane.
   double distanceToPlane(const DtPoint& p) const;

   // \return point on the plane closest to the specified point.
   DtPoint closestPointOnPlane(const DtPoint& p) const;

protected:

   // The plane is specified by the equation Ax + By + Cz + D = 0.
   double  myA;
   double  myB;
   double  myC;
   double  myD;

};

#endif