Circle Class Reference

Circles. More...

#include <circle.h>

Inheritance diagram for Circle:

Public Member Functions
	Circle ()
	Empty.
	Circle (const double &)
	Creates a circle.
	Circle (const Vector &, const Vector &, const double &)
	Creates a circle.
	Circle (const Vector &, const Vector &, const Vector &)
	Creates a circle given three vertices.
	~Circle ()
	Empty.
bool	Intersect (const Ray &, double &) const
	Compute the ray-disc intersection.
Vector	Center () const
	Gets the center of a circle.
Vector	Axis () const
	Axis of the circle.
double	Radius () const
	Radius of the circle.
double	R (const Vector &) const
	Compute the distance between a point and a circle.
Vector	Normal (const Vector &) const
	Computes the distance vector between a circle and a point.
void	Rotate (const Matrix &)
	Rotates a circle.
void	Translate (const Vector &)
	Translates a circle.
void	Scale (const double &)
	Uniformly scales a circle.
Box	GetBox () const
	Compute the axis aligned bounding box of a circle.
double	Area () const
	Area of a circle.
Vector	RandomInside (Random &=Random::R239) const
	Generate a random vector inside the circle.
Vector	RandomOn (Random &=Random::R239) const
	Generate a random vector on the circle.
Vector	Vogel (int, int) const
	Generate a spiraling vector in the disc.

Static Public Member Functions
static double	Area (const double &)
	Area of a circle given its radius.

Protected Attributes
Vector	c = Vector::Null
	Center of the circle.
Vector	axis = Vector::Z
	Axis.
double	r = 1.0
	Radius.

Static Protected Attributes
static constexpr const double	epsilon = 1.0e-10
	Internal epsilon constant.

Friends
std::ostream &	operator<< (std::ostream &s, const Circle &circle)
	Overloaded.

Detailed Description

Circles.

Circles are characterized by their center, axis and radius. They are sometimes interpreted as discs, as for ray intersection.

See also

Disc

Constructor & Destructor Documentation

Circle() [1/3]

Circle::Circle ( const double & r )

explicit

Creates a circle.

Parameters

r

Radius.

Circle() [2/3]

Circle::Circle ( const Vector & c, const Vector & axis, const double & r )

explicit

Creates a circle.

Parameters

c	Center.
axis	Axis, which should be normalized.
r	Radius.

Circle() [3/3]

Circle::Circle ( const Vector & x, const Vector & y, const Vector & z )

explicit

Creates a circle given three vertices.

Basically set the center to the center of the triangle, and compute the radius.

Parameters

x,y,z

Argument vertices

Member Function Documentation

Area() [1/2]

double Circle::Area ( ) const

inline

Area of a circle.

See also

Circle::Area(const double&)

Area() [2/2]

double Circle::Area ( const double & r )

inlinestatic

Area of a circle given its radius.

This static function avoids the creation of an instance of a circle.

See also

Circle::Area()

Parameters

r

Radius.

GetBox()

Box Circle::GetBox

(

)

const

Compute the axis aligned bounding box of a circle.

Some math will demonstrate that the box can be computed easily directly from the axis of the circle. Computations involve three square roots. For a larger but even faster bounding box, use the bounding box of the corresponding sphere:

Circle c;
Box b(c.Center(),c.Radius());

Intersect()

bool Circle::Intersect	(	const Ray &	ray,
		double &	t ) const

Compute the ray-disc intersection.

Parameters

ray	The ray.
t	Intersection depth.

Normal()

Vector Circle::Normal

(

const Vector &

p

)

const

Computes the distance vector between a circle and a point.

This function projects the point in the plane of the circle and computes the distance to the circle in its plane, before adding the extra term along the normal.

Parameters

p

Point.

R()

double Circle::R

(

const Vector &

p

)

const

Compute the distance between a point and a circle.

Cost: 10+, 8*, 1sqrt

Parameters

p

Point.

RandomInside()

Vector Circle::RandomInside

(

Random &

random = Random::R239

)

const

Generate a random vector inside the circle.

Parameters

random

Random number generator.

RandomOn()

Vector Circle::RandomOn

(

Random &

random = Random::R239

)

const

Generate a random vector on the circle.

Parameters

random

Random number generator.

Rotate()

void Circle::Rotate

(

const Matrix &

r

)

Rotates a circle.

Parameters

r	Rotation matrix.

Scale()

void Circle::Scale

(

const double &

s

)

Uniformly scales a circle.

Parameters

s	Scaling factor.

Translate()

void Circle::Translate

(

const Vector &

t

)

Translates a circle.

Parameters

t	Translation vector.

Vogel()

Vector Circle::Vogel	(	int	i,
		int	n ) const

Generate a spiraling vector in the disc.

Parameters

i	Integer, should be <n.
n	Number of points.

Friends And Related Symbol Documentation

operator<<

std::ostream & operator<< ( std::ostream & s, const Circle & circle )

friend

Overloaded.

Parameters

s	Stream.
circle	The circle.