DiscTile Class Reference

Poisson tiling. More...

#include <sampling.h>

Public Member Functions
	DiscTile ()
	Empty.
	DiscTile (const double &, const double &, const QVector< Vector2 > &)
	Create a Poisson disc sampling over a square domain.
	DiscTile (const double &, const double &, int, Random &=Random::R239)
	Create a poisson sampling in a square domain.
	DiscTile (const double &, const double &, int, const QVector< Vector2 > &, Random &=Random::R239)
	Create a poisson sampling in a square domain.
	~DiscTile ()
	Empty.
void	Relaxation (const double &=1.0/4.0)
	Perform a relaxation step over the Poisson-Disc distribution.
void	Relaxation (int, const double &=1.0/4.0)
	Perform a relaxation step over the Poisson-Disc distribution.
void	Scramble ()
	Scramble the points inside the generated tile.
void	Draw (QGraphicsScene &) const
	Draw the distribution.
Box2	GetBox () const
	Return the box.
double	Radius () const
	Return the radius.
Vector2	Vertex (int) const
	Getter on the i-th sample.
Vector2	Vertex (int, int, int) const
	Compute the i-th sample for a displaced tile.
Vector2	Vertex (const QPoint &, int) const
	Compute the i-th sample for a displaced tile.
const QVector< Vector2 >	GetSet () const
	Return the vector containing the samples.
int	Size () const
	Return the number of samples.
void	Scale (const double &)
	Scale a disc tile.
QVector< Vector2 >	Sample (const Box2 &, double(*)(const Vector2 &)) const
	Sample a domain according to an input importance function.
QVector< Vector2 >	Sample (const ScalarField2 &) const
	Sample a domain according to an input importance function.
QVector< Vector2 >	Sample (const Box2 &) const
	Sample a domain according to an input importance function.
double	Packing () const
	Compute the packing density.

Static Public Member Functions
static bool	Check (const Vector2 &, const QVector< Vector2 > &, double)
	Performs a Poisson disc check on a set of point and a candidate position.

Static Public Attributes
static const DiscTile	UnitReference
	Reference unit disc tile with 231 discs.

Protected Member Functions
void	Generate (int, Random &=Random::R239)
	Generate the poisson sampling of the domain.
bool	Intersect (const Vector2 &, bool=true) const
	Check if a disc intersect existing discs inside the tile, with or without toric constraints.

Protected Attributes
double	s = 0.0
	Size.
double	r = 0.0
	Radius.
double	e = 0.0
	Squared radius with small epsilon tolerance.
QVector< Vector2 >	p
	Set of samples.

Friends
std::ostream &	operator<< (std::ostream &s, const DiscTile &disctile)
	Overloaded.

Detailed Description

Poisson tiling.

Can be used for importance sampling from Template Poisson disk tiles, Ares Lagae, Philip Dutré. See Ares Lagae, Philip Dutré. A procedural object distribution function. ACM Transactions on Graphics. 24(4), 1442–1461.

Constructor & Destructor Documentation

DiscTile() [1/4]

DiscTile::DiscTile ( )

explicit

Empty.

Initialize a poisson disc tiling.

DiscTile() [2/4]

DiscTile::DiscTile ( const double & s, const double & r, const QVector< Vector2 > & v )

explicit

Create a Poisson disc sampling over a square domain.

Parameters

s	Size of the side of the square.
r	Radius of the samples.
v	Set of points.

DiscTile() [3/4]

DiscTile::DiscTile ( const double & s, const double & r, int n, Random & ra = Random::R239 )

explicit

Create a poisson sampling in a square domain.

Parameters

s	Size of the side of the square.
r	Radius of the samples.
n	Maximum number of samples in the dart throwing process. Note that the number of samples will be different.
ra	Random number generator.

DiscTile() [4/4]

DiscTile::DiscTile ( const double & s, const double & r, int n, const QVector< Vector2 > & p, Random & ra = Random::R239 )

explicit

Create a poisson sampling in a square domain.

Parameters

s	Size of the side of the square.
r	Radius of the samples.
n	Maximum number of samples in the dart throwing process. Note that the number of samples will be different.
p	Set of samples that will be in the tile.
ra	Random number generator.

Member Function Documentation

Check()

bool DiscTile::Check ( const Vector2 & p, const QVector< Vector2 > & s, double r )

static

Performs a Poisson disc check on a set of point and a candidate position.

Returns true if the candidate intersects with the distribution, false otherwise.

Parameters

p	Candidate position.
s	Set of point.
r	Poisson disc radius.

Draw()

void DiscTile::Draw

(

QGraphicsScene &

scene

)

const

Draw the distribution.

Parameters

scene

The graphics scene.

Generate()

void DiscTile::Generate ( int n, Random & random = Random::R239 )

protected

Generate the poisson sampling of the domain.

Parameters

n	Number of darts thrown on the domain. Note that the number of generated samples will be less than n.
random	Random number generator.

Intersect()

bool DiscTile::Intersect ( const Vector2 & q, bool t = true ) const

protected

Check if a disc intersect existing discs inside the tile, with or without toric constraints.

This complexity is O(n), thus the function is expensive should it be called many times.

Parameters

q	Point.
t	Toric constraint, set to true as default.

Packing()

double DiscTile::Packing

(

)

const

Compute the packing density.

See also

DiscTile::Packing()

Relaxation() [1/2]

void DiscTile::Relaxation

(

const double &

c = 1.0 / 4.0

)

Perform a relaxation step over the Poisson-Disc distribution.

Parameters

c	Relaxation coefficient, it is the fraction of the Poisson radius.

Relaxation() [2/2]

void DiscTile::Relaxation	(	int	n,
		const double &	c = 1.0 / 4.0 )

Perform a relaxation step over the Poisson-Disc distribution.

Parameters

c	Relaxation coefficient, it the fraction of the radius of the Poisson distribution.
n	Number of steps.

Sample() [1/3]

QVector< Vector2 > DiscTile::Sample

(

const Box2 &

box

)

const

Sample a domain according to an input importance function.

Parameters

box

The box.

Sample() [2/3]

QVector< Vector2 > DiscTile::Sample	(	const Box2 &	b,
		double(*	f )(const Vector2 &) ) const

Sample a domain according to an input importance function.

Parameters

b	The box.
f	Importance function.

Sample() [3/3]

QVector< Vector2 > DiscTile::Sample

(

const ScalarField2 &

s

)

const

Sample a domain according to an input importance function.

Parameters

s	Scalar field defining the importance function.

Scale()

void DiscTile::Scale

(

const double &

s

)

Scale a disc tile.

Parameters

s	Scaling factor.

Scramble()

void DiscTile::Scramble

(

)

Scramble the points inside the generated tile.

Use a modified version of the Fisher-Yates algorithm.

See also

Shuffle::Table

Vertex() [1/3]

Vector2 DiscTile::Vertex ( const QPoint & t, int i ) const

inline

Compute the i-th sample for a displaced tile.

Parameters

t	Integer coordinates of the tile.
i	Sample index.

Vertex() [2/3]

Vector2 DiscTile::Vertex ( int i ) const

inline

Getter on the i-th sample.

Parameters

i	Sample index.

Vertex() [3/3]

Vector2 DiscTile::Vertex ( int x, int y, int i ) const

inline

Compute the i-th sample for a displaced tile.

Parameters

x,y	Integer coordinates of the tile.
i	Sample index.

Friends And Related Symbol Documentation

operator<<

std::ostream & operator<< ( std::ostream & s, const DiscTile & disctile )

friend

Overloaded.

Parameters

s	Stream.
disctile	The disc tile.