PerlinSdf Class Reference

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.
Real	lerp (const Real t, const Real a, const Real b) const
	Interpolation function.
Real	fade (const Real t) const
	Fade function.
Real	grad (const int hash, const double x, const double y, const double z) const
	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

noise()

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

octaveNoise()

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

protected

Octave noise function. Returns noise over over several octaves.

normFrac;

random()

int PerlinSdf::random ( const int  i )

static

Simple random number generator.

Parameters

[in]

seed

value()

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

virtual

Level-set function.

Parameters

[in]

a_pos

Position

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.

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

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