Class that implements the improved Perlin noise function. More...

#include <CD_PerlinSdf.H>

Inheritance diagram for PerlinSdf:

Collaboration diagram for PerlinSdf:

Public Member Functions
	PerlinSdf (const Real a_noiseAmp, const RealVect &a_noiseFreq, const Real a_persistence, const int a_octaves, const bool a_reseed=false)
	Full constructor.

	PerlinSdf (const PerlinSdf &a_inputIF)
	Copy constructor.

virtual	~PerlinSdf ()
	Destructor.

virtual Real	value (const RealVect &a_pos) const
	Level-set function.

virtual BaseIF *	newImplicitFunction () const
	Factory method.

Static Public Member Functions
static int	random (const int i)
	Simple random number generator.

Protected Member Functions
virtual void	reseed ()
	Reseed function.

double	noise (const double a_x, const double a_y, const double a_z) const
	Ken Perlin's 3D noise function.

Real	noise (const RealVect &a_pos) const
	Chombo interface to Perlin noise function.

Real	octaveNoise (const RealVect &a_pos) const
	Octave noise function. Returns noise over over several octaves.

Static Protected Member Functions
static Real	lerp (const Real t, const Real a, const Real b)
	Interpolation function.

static Real	fade (const Real t)
	Fade function.

static Real	grad (const int hash, const double x, const double y, const double z)
	Gradient function using hash table lookup.

Protected Attributes
RealVect	m_noiseFreq
	Perlin noise frequency.

Real	m_noiseAmp
	Perlin noise amplitude.

Real	m_persistence
	Perlin octave fade factor.

int	m_octaves
	Number of octaves to use for noise.

double	p [512]
	Permutation table.

Static Protected Attributes
static constexpr int	m_permutationTable [256]
	Ken Perlin's original permutation array.

Detailed Description

Class that implements the improved Perlin noise function.

Typically, you will use this function to displace a level-set function by using SumIF. However, Perlin noise is also a signed distance function, and so it can be used as an implicit function as well.

Note: See the original paper by Ken Perlin for understanding the algorithm: "Improving Noise. Ken Perlin (2002)"

Constructor & Destructor Documentation

◆ PerlinSdf() [1/2]

PerlinSdf::PerlinSdf	(	const Real	a_noiseAmp,
		const RealVect &	a_noiseFreq,
		const Real	a_persistence,
		const int	a_octaves,
		const bool	a_reseed = `false`
	)

Full constructor.

Parameters

[in]	a_noiseAmp	Noise amplitude
[in]	a_noiseFreq	Base frequency
[in]	a_octaves	Number of octaves to use for Perlin noise
[in]	a_persistence	Reduction factor for each octave
[in]	a_reseed	Reseed permutation vector (true) or use Ken Perlin's original one (false)

◆ PerlinSdf() [2/2]

PerlinSdf::PerlinSdf ( const PerlinSdf & a_inputIF )

Copy constructor.

Parameters

[in] a_inputIF Input PerlinSdf

Member Function Documentation

◆ fade()

Real PerlinSdf::fade ( const Real t )

staticprotected

Fade function.

Returns: Return value

Parameters

[in] t Description

◆ grad()

Real PerlinSdf::grad	(	const int	hash,
		const double	x,
		const double	y,
		const double	z
	)

staticprotected

Gradient function using hash table lookup.

Returns: Return value

Parameters

[in]	hash	Description
[in]	x	Description
[in]	y	Description
[in]	z	Description

◆ lerp()

Real PerlinSdf::lerp	(	const Real	t,
		const Real	a,
		const Real	b
	)

staticprotected

Interpolation function.

Returns: Return value

Parameters

[in]	t	Description
[in]	a	Description
[in]	b	Description

◆ newImplicitFunction()

BaseIF * PerlinSdf::newImplicitFunction ( ) const

virtual

Factory method.

Returns: New copy of this implicit function

◆ noise() [1/2]

double PerlinSdf::noise	(	const double	a_x,
		const double	a_y,
		const double	a_z
	)		const

protected

Ken Perlin's 3D noise function.

For 2D, we use Ken Perlin's function with z = 0

Parameters

[in]	a_x	Position
[in]	a_y	Position
[in]	a_z	Position

Returns: Return value

◆ noise() [2/2]

Real PerlinSdf::noise ( const RealVect & a_pos ) const

protected

Chombo interface to Perlin noise function.

Returns: Return value

Parameters

[in,out] a_pos Description

◆ octaveNoise()

Real PerlinSdf::octaveNoise ( const RealVect & a_pos ) const

protected

Octave noise function. Returns noise over over several octaves.

Returns: Return value

Parameters

[in,out] a_pos Description

normFrac;

◆ random()

int PerlinSdf::random ( const int i )

static

Simple random number generator.

Returns: Return value

Parameters

[in] i I

◆ value()

Real PerlinSdf::value ( const RealVect & a_pos ) const

virtual

Level-set function.

Parameters

[in] a_pos Position

Returns: Function value at the given point

Member Data Documentation

◆ m_permutationTable

constexpr int PerlinSdf::m_permutationTable

staticconstexprprotected

Initial value:

= {
    151, 160, 137, 91,  90,  15,  131, 13,  201, 95,  96,  53,  194, 233, 7,   225, 140, 36,  103, 30,  69,  142,
    8,   99,  37,  240, 21,  10,  23,  190, 6,   148, 247, 120, 234, 75,  0,   26,  197, 62,  94,  252, 219, 203,
    117, 35,  11,  32,  57,  177, 33,  88,  237, 149, 56,  87,  174, 20,  125, 136, 171, 168, 68,  175, 74,  165,
    71,  134, 139, 48,  27,  166, 77,  146, 158, 231, 83,  111, 229, 122, 60,  211, 133, 230, 220, 105, 92,  41,
    55,  46,  245, 40,  244, 102, 143, 54,  65,  25,  63,  161, 1,   216, 80,  73,  209, 76,  132, 187, 208, 89,
    18,  169, 200, 196, 135, 130, 116, 188, 159, 86,  164, 100, 109, 198, 173, 186, 3,   64,  52,  217, 226, 250,
    124, 123, 5,   202, 38,  147, 118, 126, 255, 82,  85,  212, 207, 206, 59,  227, 47,  16,  58,  17,  182, 189,
    28,  42,  223, 183, 170, 213, 119, 248, 152, 2,   44,  154, 163, 70,  221, 153, 101, 155, 167, 43,  172, 9,
    129, 22,  39,  253, 19,  98,  108, 110, 79,  113, 224, 232, 178, 185, 112, 104, 218, 246, 97,  228, 251, 34,
    242, 193, 238, 210, 144, 12,  191, 179, 162, 241, 81,  51,  145, 235, 249, 14,  239, 107, 49,  192, 214, 31,
    181, 199, 106, 157, 184, 84,  204, 176, 115, 121, 50,  45,  127, 4,   150, 254, 138, 236, 205, 93,  222, 114,
    67,  29,  24,  72,  243, 141, 128, 195, 78,  66,  215, 61,  156, 180}

Ken Perlin's original permutation array.

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

Source/ImplicitFunctions/CD_PerlinSdf.H
Source/ImplicitFunctions/CD_PerlinSdf.cpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Static Protected Member Functions

Protected Attributes

Static Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ PerlinSdf() [1/2]

◆ PerlinSdf() [2/2]

Member Function Documentation

◆ fade()

◆ grad()

◆ lerp()

◆ newImplicitFunction()

◆ noise() [1/2]

◆ noise() [2/2]

◆ octaveNoise()

◆ random()

◆ value()

Member Data Documentation

◆ m_permutationTable