PerlinNoise Class Reference

Generate 3D perlin noise and multi-layered noise. More...

#include <PerlinNoise.hpp>

Public Member Functions
	PerlinNoise ()
void	generate (Image &image, uint channel, float scale, float z, const glm::vec3 &offset=glm::vec3(0.0f))
void	generatePeriodic (Image &image, uint channel, float scale, float z, const glm::vec3 &offset=glm::vec3(0.0f))
void	generateLayers (Image &image, uint channel, int octaves, float gain, float lacunarity, float scale, const glm::vec3 &offset=glm::vec3(0.0f))
void	reseed ()

Private Member Functions
float	dotGrad (const glm::ivec3 &ip, const glm::vec3 &dp)
float	perlin (const glm::vec3 &p, const glm::ivec3 &w=glm::ivec3(kHashTableSize-1))

Private Attributes
std::array< int, 2 *kHashTableSize >	_hashes
	Permutation table.
Image	_directions
	random unit sphere directions.

Static Private Attributes
static const int	kHashTableSize = 256
	Number of hashes used for the generation, limit the periodicity.

Detailed Description

Generate 3D perlin noise and multi-layered noise.

Constructor & Destructor Documentation

PerlinNoise()

PerlinNoise::PerlinNoise

(

)

Constructor. Initialize the randomness table.

Member Function Documentation

dotGrad()

float PerlinNoise::dotGrad ( const glm::ivec3 &  ip, const glm::vec3 &  dp  )

private

Compute the dot product between a direction vector and the gradient at a (ix, iy, iz) location on the grid.

Parameters

ip	the grid vertex location
dp	the direction vector

Returns

the dot product

generate()

void PerlinNoise::generate	(	Image &	image,
		uint	channel,
		float	scale,
		float	z,
		const glm::vec3 &	offset = glm::vec3(0.0f)
	)

Fill a component of an image with Perlin noise in [-1,1].

Parameters

image	image to fill with preset dimensions
channel	the channel of the image to fill
scale	the frequency, in pixels
z	the depth (in pixels) at which the 3D Perlin noise should be sampled
offset	the origin in sampled noise space

generateLayers()

void PerlinNoise::generateLayers	(	Image &	image,
		uint	channel,
		int	octaves,
		float	gain,
		float	lacunarity,
		float	scale,
		const glm::vec3 &	offset = glm::vec3(0.0f)
	)

Fill a component of an image with multi-layered Perlin noise (FBM).

Parameters

image	image to fill with preset dimensions
channel	the channel of the image to fill
octaves	number of layers
gain	the amplitude ratio between a layer and the previous one
lacunarity	the frequency ratio between a layer and the previous one
scale	the base frequency, in pixels
offset	the origin in sampled noise space

generatePeriodic()

void PerlinNoise::generatePeriodic	(	Image &	image,
		uint	channel,
		float	scale,
		float	z,
		const glm::vec3 &	offset = glm::vec3(0.0f)
	)

Fill a component of an image with tiling Perlin noise in [-1,1].

Parameters

image	image to fill with preset dimensions
channel	the channel of the image to fill
scale	the frequency, in pixels
z	the depth (in pixels) at which the 3D Perlin noise should be sampled
offset	the origin in sampled noise space

Note

The scale might internally be adjusted to ensure periodicity.

perlin()

float PerlinNoise::perlin ( const glm::vec3 &  p, const glm::ivec3 &  w = glm::ivec3(kHashTableSize-1)  )

private

Evaluate Perlin noise for a given location in noise space.

Parameters

p	location
w	the tiling period to apply on each axis

Returns

the noise value in [-1, 1]

reseed()

void PerlinNoise::reseed

(

)

Regenerate the randomness table with new values.

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

• src/engine/generation/PerlinNoise.hpp
• src/engine/generation/PerlinNoise.cpp