disk Class Reference

A circular disk in 3D space. More...

#include <disk.h>

Collaboration diagram for disk:

List of all members.

Public Member Functions
	disk (point3< double > const &nml_, point3< double > const &pos_, doublec radius_)
	Specify the disk in 3D space.
boolc	intersects (point3< double > &p0, point3< double > &p1, disk const &D2) const
	Find if the two disks intersect, and if so return the first and last intersection points on the line of intersection.
boolc	intersects (point3< double > &p0, point3< double > &p1, plane const &w2) const
	Does this disk intersect with the plane?
	operator stringc () const
	Serialize this object by writing it out as a string.
Public Attributes
point3< double >	nml
	Normal or the disks orientation.
point3< double >	pos
	Position.
double	radius
	The circles radius.

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Detailed Description

A circular disk in 3D space.

Definition at line 11 of file disk.h.

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Constructor & Destructor Documentation

disk::disk	(	point3< double > const &	nml_,
		point3< double > const &	pos_,
		doublec	radius_
	)

Specify the disk in 3D space.

Definition at line 11 of file disk.cpp.

  : nml(nml_), pos(pos_), radius(radius_)
{
//cout << SHOW(nml.dot()) << endl;
//  assert(nml.dot()<=1.0+zero<double>::val);
}

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Member Function Documentation

boolc disk::intersects	(	point3< double > &	p0,
		point3< double > &	p1,
		plane const &	w2
	)			const

Does this disk intersect with the plane?

Definition at line 99 of file disk.cpp.

References point3< T >::dot(), crossproduct::evalxyz(), circleLine::intersection2D(), point3< T >::normalize(), point2< T >::x, and point2< T >::y.

{
  plane w1(nml,nml.dot(pos));

  // linept + linegrad*t
  point3<double> linept;
  point3<double> linegrad;

  bool res = w1.intersects(linept,linegrad,w2); 
  if (res==false)
    return false;

  // Make a coordinate system relative to the disks origin.
  point3<double> q0(linept-pos);
  point3<double> q1(linept+linegrad-pos);

  // armx and army are the arms of the 2D coordinate system
  // in 3D space.
  point3<double> armx(q0);
  if (zero<double>::test(armx.dot()))
  {
    //t=1 case
    armx += linegrad;
    if (zero<double>::test(armx.dot()))
      return false;

    q0=linept+linegrad-pos;
    q1=linept-pos;
  }
  armx.normalize();

  point3<double> army;
  crossproduct::evalxyz(army,armx,nml);
  assert(zero<double>::test(army.dot())==false);

  // Get the line points in the 2D coordinate system representation.
  point2<double> Q0(armx.dot(q0),0.0);
  assert(zero<double>::test(army.dot(q0)));
  point2<double> Q1(armx.dot(q1),army.dot(q1));

  point2<double> P0;
  point2<double> P1;
  res = circleLine::intersection2D(P0,P1,radius,Q0,Q1);
  if (res==false)
    return false;

  p0 = armx*P0.x + army*P0.y + pos;
  p1 = armx*P1.x + army*P1.y + pos;

  return true;
}

boolc disk::intersects	(	point3< double > &	p0,
		point3< double > &	p1,
		disk const &	D2
	)			const

Find if the two disks intersect, and if so return the first and last intersection points on the line of intersection.

Definition at line 24 of file disk.cpp.

References point3< T >::dot(), intersects(), nml, pos, intervalintersection::unordered(), point3< T >::x, and point3< T >::y.

Referenced by intersects(), disktest::test00(), diskinttest::update01(), diskinttest::update02(), and diskinttest::update03lineline().

{
  // Four intersection points of disks on line.
  point3<double> q[4];

  plane w2(D2.nml,D2.nml.dot(D2.pos));
  if (intersects(q[0],q[1],w2)==false)
    return false;

  plane w1(nml,nml.dot(pos));
  if (D2.intersects(q[2],q[3],w1)==false)
    return false;

  // Given line segments [q0,q1] and [q3,q4],
  // determine if they overlap and the start and end points.
  // These lines should be colinear.
  // <TODO>

  
  point3<double> linegrad(q[2]-q[0]);
  if (zero<double>::test(linegrad.dot()))
  {
    linegrad = q[3]-q[0];
    // The disks are touching.
    if (zero<double>::test(linegrad.dot()))
    {
      p0 = q[0];
      p1 = q[0];
      return true;
    }
  };

  // Let the line by q[0] + linegrad*t.

  double t[4];
  t[0] = 0.0;

  if (zero<double>::test(linegrad.x*linegrad.x))
  {
    assert(zero<double>::test(linegrad.y*linegrad.y)==false);

    for (uint i=1; i<4; ++i)
      t[i] = (q[i].y-q[0].y) / linegrad.y;
  }  
  else
  {
    for (uint i=1; i<4; ++i)
      t[i] = (q[i].x-q[0].x) / linegrad.x;
  }

#ifndef NDEBUG
  for (uint i=0; i<4; ++i)
  {
    //cout << SHOW( (q[i]-(q[0]+linegrad*t[i])).dot() ) << endl;
    assert( zero<double>::test((q[i]-(q[0]+linegrad*t[i])).dot()) );
  }
#endif

  double c0;
  double c1;
  if (intervalintersection::unordered(c0,c1,t[0],t[1],t[2],t[3])==false)
    return false;

  p0 = q[0] + linegrad*c0;
  p1 = q[0] + linegrad*c1;

  return true;
}

disk::operator stringc

(

)

const

Serialize this object by writing it out as a string.

Definition at line 155 of file disk.cpp.

References nml, pos, radius, point3< T >::x, point3< T >::y, and point3< T >::z.

{
  stringstream ss;
  ss << nml.x << " " << nml.y << " " << nml.z << "  ";
  ss << pos.x << " " << pos.y << " " << pos.z << "  "; 
  ss << radius;

  return ss.str();
}

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Member Data Documentation

point3<double> disk::nml

Normal or the disks orientation.

Definition at line 16 of file disk.h.

Referenced by intersects(), diskinttest::keyboard01(), diskinttest::keyboard02(), operator stringc(), diskinttest::test01(), diskinttest::test02(), diskinttest::update01(), diskinttest::update02(), and diskinttest::update03lineline().

point3<double> disk::pos

Position.

Definition at line 19 of file disk.h.

Referenced by intersects(), diskinttest::keyboard01(), diskinttest::keyboard02(), operator stringc(), diskinttest::test01(), diskinttest::test02(), diskinttest::update01(), diskinttest::update02(), and diskinttest::update03lineline().

double disk::radius

The circles radius.

Definition at line 22 of file disk.h.

Referenced by diskinttest::keyboard02(), operator stringc(), diskinttest::test01(), diskinttest::test02(), diskinttest::update02(), and diskinttest::update03lineline().

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The documentation for this class was generated from the following files:

• mathlib/disk.h
• mathlib/disk.cpp