The finite amortized 2D noise class. More...

#include <FiniteAmortizedNoise2D.h>

Public Member Functions
	CFiniteAmortizedNoise2D (const unsigned n)
	Constructor.

	~CFiniteAmortizedNoise2D ()
	Destructor.

float	generate (int x, int y, const int m0, const int m1, const int n, float **cell)
	Generate a cell of 2D amortized noise.

Private Member Functions
void	initPerlinNoiseTables ()
	Initialize Perlin noise tables.

float	getRandomUnitFloat ()
	Random float in range [-1, 1].

unsigned int	h (const unsigned int x)
	1D hash function.

unsigned int	h (const unsigned int x, const unsigned int y)
	2D hash function.

void	FillUp (float *t, const float s, const int n)
	Fill amortized noise table bottom up.

void	FillDn (float *t, const float s, const int n)
	Fill amortized noise table top down.

void	initEdgeTables (const int x, const int y, const int n)
	Initialize the amortized noise tables.

void	initSplineTable (const int n)
	Initialize the spline table.

float	getNoise (const int i, const int j)
	Get one point of amortized noise.

void	getNoise (const int n, const int i0, const int j0, float **cell)
	Get 1 octave of amortized noise into cell.

void	addNoise (const int n, const int i0, const int j0, const float scale, float **cell)
	Add 1 octave of amortized noise into cell.

Private Attributes
float	g2 [B][2]
	Perlin gradient table.

int	p [B]
	Perlin permutation table.

float *	uax
	X coordinate of u used to compute a.

float *	vax
	X coordinate of v used to compute a.

float *	ubx
	X coordinate of u used to compute b.

float *	vbx
	X coordinate of v used to compute b.

float *	uay
	Y coordinate of u used to compute a.

float *	vay
	Y coordinate of v used to compute a.

float *	uby
	Y coordinate of u used to compute b.

float *	vby
	Y coordinate of v used to compute b.

float *	spline
	Spline table.

Detailed Description

The 2D amortized noise class implements the 2D amortized noise algorithm using Perlin's finite hash table.

Constructor & Destructor Documentation

CFiniteAmortizedNoise2D::CFiniteAmortizedNoise2D ( const unsigned n )

Constructor.

Parameters

n	Cell size.

Member Function Documentation

void CFiniteAmortizedNoise2D::addNoise	(	const int	n,
		const int	i0,
		const int	j0,
		const float	scale,
		float **	cell
	)

private

Add a single octave of noise into a subcell. This differs from CInfiniteAmortizedNoise2D::getNoise in that it adds the noise to the cell instead of copying it there.

Parameters

n	Granularity.
i0	x offset of this subcell in cell.
j0	y offset of this subcell in cell.
scale	Noise is to be rescaled by this factor.
cell	Noise cell.

void CFiniteAmortizedNoise2D::FillDn	(	float *	t,
		const float	s,
		const int	n
	)

private

Fill amortized noise table top down.

Parameters

t	Amortized noise table.
s	Initial value.
n	Granularity.

void CFiniteAmortizedNoise2D::FillUp	(	float *	t,
		const float	s,
		const int	n
	)

private

Fill amortized noise table bottom up.

Parameters

t	Amortized noise table.
s	Initial value.
n	Granularity.

float CFiniteAmortizedNoise2D::generate	(	int	x,
		int	y,
		const int	m0,
		const int	m1,
		const int	n,
		float **	cell
	)

Generate a cell of 1/f amortized noise with persistence 0.5 and lacunarity 2.0.

Parameters

x	x coordinate of top left corner of cell.
y	y coordinate of top left corner of cell.
m0	First octave.
m1	Last octave.
n	Granularity.
cell	Cell to put generated noise into.

Returns: Multiply noise by this to get into the range -1..1

float CFiniteAmortizedNoise2D::getNoise	(	const int	i,
		const int	j
	)

private

Compute a single point of a single octave of Perlin noise. This is similar to Perlin's noise2 function except that it substitutes table lookups for floating point multiplication.

Parameters

i	x coordinate of point.
j	y coordinate of point.

Returns: Noise value at (i, j).

void CFiniteAmortizedNoise2D::getNoise	(	const int	n,
		const int	i0,
		const int	j0,
		float **	cell
	)

private

Get a single octave of noise into a subcell. This differs from CInfiniteAmortizedNoise2D::addNoise in that it copies the noise to the cell instead of adding it in.

Parameters

n	Granularity.
i0	x offset of this subcell in cell.
j0	y offset of this subcell in cell.
cell	Noise cell.

float CFiniteAmortizedNoise2D::getRandomUnitFloat ( )

private

Get a random unit floating point number.

Returns: Random floating point number >=-1 and <=1.

unsigned int CFiniteAmortizedNoise2D::h ( const unsigned int x )

private

A 1D hash function. Hash one dimension into a single unsigned int.

Parameters

x	value to be hashed.

Returns: Hash of x.

unsigned int CFiniteAmortizedNoise2D::h	(	const unsigned int	x,
		const unsigned int	y
	)

private

A 2D hash function. Hash two dimensions into a single unsigned int.

Parameters

x	X coordinate of value to be hashed.
y	Y coordinate of value to be hashed.

Returns: Hash of (x, y).

void CFiniteAmortizedNoise2D::initEdgeTables	(	const int	x0,
		const int	y0,
		const int	n
	)

private

Initialize the amortized noise tables.

Parameters

x0	x coordinate of top left corner of cell.
y0	y coordinate of top left corner of cell.
n	Granularity.

void CFiniteAmortizedNoise2D::initPerlinNoiseTables ( )

private

Initialize the Perlin noise tables. Loads p with a random permutation and g2 with a randomly chosen selection of unit gradients.

void CFiniteAmortizedNoise2D::initSplineTable ( const int n )

private

Initialize the spline table.

Parameters

n	Granularity.

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

Public Member Functions

Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation