CInfiniteAmortizedNoise2D Class Reference

The amortized 2D noise class. More...

#include <InfiniteAmortizedNoise2D.h>

Inheritance diagram for CInfiniteAmortizedNoise2D:

Public Member Functions
	CInfiniteAmortizedNoise2D (const unsigned n, const unsigned int s)
	Constructor. More...
	~CInfiniteAmortizedNoise2D ()
	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. More...

Protected Member Functions
virtual unsigned int	h (const unsigned int x, const unsigned int y)
	2D hash function. More...
void	FillUp (float *t, const float s, const int n)
	Fill amortized noise table bottom up. More...
void	FillDn (float *t, const float s, const int n)
	Fill amortized noise table top down. More...
virtual void	initEdgeTables (const int x, const int y, const int n)
	Initialize the amortized noise tables. More...
void	initSplineTable (const int n)
	Initialize the spline table. More...
float	getNoise (const int i, const int j)
	Get one point of amortized noise. More...
void	getNoise (const int n, const int i0, const int j0, float **cell)
	Get 1 octave of amortized noise into cell. More...
void	addNoise (const int n, const int i0, const int j0, const float scale, float **cell)
	Add 1 octave of amortized noise into cell. More...

Protected Attributes
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.
unsigned int	seed
	Hash seed.

Detailed Description

The 2D amortized noise class implements the 2D infinite amortized noise algorithm.

Constructor & Destructor Documentation

CInfiniteAmortizedNoise2D()

CInfiniteAmortizedNoise2D::CInfiniteAmortizedNoise2D	(	const unsigned	n,
		const unsigned int	s
	)

Constructor.

Parameters

n	Cell size.
s	Hash function seed.

Member Function Documentation

addNoise()

void CInfiniteAmortizedNoise2D::addNoise ( const int  n, const int  i0, const int  j0, const float  scale, float **  cell  )

protected

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.

FillDn()

void CInfiniteAmortizedNoise2D::FillDn ( float *  t, const float  s, const int  n  )

protected

Fill amortized noise table top down.

Parameters

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

FillUp()

void CInfiniteAmortizedNoise2D::FillUp ( float *  t, const float  s, const int  n  )

protected

Fill amortized noise table bottom up.

Parameters

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

generate()

float CInfiniteAmortizedNoise2D::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

getNoise() [1/2]

float CInfiniteAmortizedNoise2D::getNoise ( const int  i, const int  j  )

protected

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 pointmultiplication as described in the paper "Amortized Noise".

Parameters

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

Returns

Noise value at (x, y).

getNoise() [2/2]

void CInfiniteAmortizedNoise2D::getNoise ( const int  n, const int  i0, const int  j0, float **  cell  )

protected

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.

h()

unsigned int CInfiniteAmortizedNoise2D::h ( const unsigned int  x, const unsigned int  y  )

protectedvirtual

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

Parameters

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

Returns

Hash of (x, y).

initEdgeTables()

void CInfiniteAmortizedNoise2D::initEdgeTables ( const int  x0, const int  y0, const int  n  )

protectedvirtual

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.

Reimplemented in CTerrainGenerator.

initSplineTable()

void CInfiniteAmortizedNoise2D::initSplineTable ( const int  n )

protected

Initialize the spline table as described in the paper "Amortized Noise".

Parameters

n	Granularity.

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

• InfiniteAmortizedNoise2D.h
• InfiniteAmortizedNoise2D.cpp