ParametrizedLine.h

// -*- C++ -*-

#if !defined(__geom_ParametrizedLine_h__)
#define __geom_ParametrizedLine_h__

// If we are debugging the whole geom namespace.
#if defined(DEBUG_geom) && !defined(DEBUG_ParametrizedLine)
#define DEBUG_ParametrizedLine
#endif

#include <iostream>
#include <cassert>
#include <cmath>

#include "SegmentMath.h"

BEGIN_NAMESPACE_GEOM


template<int N, typename T = double>
class ParametrizedLine {
private:

  //
  // Private types.
  //

  typedef SegmentMath<N,T> Segment;

public:

  //
  // Public types.
  //

  typedef T Number;
  typedef ads::FixedArray<N,Number> Point;
  typedef ads::FixedArray<1,Number> ParameterPoint;

private:

  //
  // Member data
  //

  // The line segment that determines the line and the parametrization.
  Segment _segment;
  // The derivative of position is a constant, so we store it.
  Point _derivative;

public:

  //--------------------------------------------------------------------------


  ParametrizedLine()
  {}

  ParametrizedLine(const Point& source, const Point& target) : 
    _segment(source, target),
    _derivative(_segment.getLength() * _segment.getTangent()) {
    assert(isValid());
  }

  void
  build(const Point& source, const Point& target) {
    _segment.make(source, target);
    _derivative = _segment.getLength() * _segment.getTangent();
    assert(isValid());
  }

  ParametrizedLine(const ParametrizedLine& other) : 
    _segment(other._segment),
    _derivative(other._derivative)
  {}

  ParametrizedLine& 
  operator=(const ParametrizedLine& other) {
    if (this != &other) {
      _segment = other._segment;
      _derivative = other._derivative;
    }
    return *this;
  }

  ~ParametrizedLine()
  {}

  //--------------------------------------------------------------------------


  Point 
  computePosition(const ParameterPoint& parameterPoint) const {
    return _segment.getSource() + 
      (parameterPoint[0] * _segment.getLength()) * _segment.getTangent();
  }

  const Point&
  computeDerivative(const ParameterPoint& parameterPoint) const {
    return _derivative;
  }

  //--------------------------------------------------------------------------


  bool
  operator==(const ParametrizedLine& other) {
    return _segment == other._segment && _derivative == other._derivative;
  }


  bool
  operator!=(const ParametrizedLine& other) {
    return ! operator==(other);
  }

  //--------------------------------------------------------------------------
  // Private member functions.

private:
  
  // Check that the length is non-zero.
  bool
  isValid() {
    return _segment.getLength() != 0;
  }
};


END_NAMESPACE_GEOM

#endif

---