Random Class Reference

Generate seedable random numbers of various types and in multiple intervals. Handles per-thread random number generators. More...

#include <Random.hpp>

Classes
struct	LocalMT19937
	A MT19937 generator seeded using the shared generator. Used to provide per-thread MT19937 generators in a thread-safe way. More...

Static Public Member Functions
static void	seed ()
static void	seed (unsigned int seedValue)
static unsigned int	getSeed ()
static int	Int (int min, int max)
static float	Float ()
static float	Float (float min, float max)
static glm::vec3	Color ()
static glm::vec2	sampleDisk ()
static glm::vec3	sampleSphere ()
static glm::vec3	sampleCosineHemisphere ()
template<typename T >
static void	shuffle (std::vector< T > &items)

Static Private Attributes
static unsigned int	_seed
	The current main seed.
static std::mt19937	_shared
	Shared randomness generator, used for seeding per-thread generators. More...
static std::mutex	_lock
	The lock for the shared generator.
static thread_local LocalMT19937	_thread
	Per-thread randomness generator, seeded using the shared generator.

Detailed Description

Generate seedable random numbers of various types and in multiple intervals. Handles per-thread random number generators.

Member Function Documentation

Color()

glm::vec3 Random::Color ( )

static

Generate a random color in RGB color space. Internally a HSV color with reasonable saturation and luminance is generated and converted to RGB.

Returns

an RGB triplet.

Float() [1/2]

float Random::Float ( )

static

Generate a float in [0.0, 1.0)

Returns

a float in [0.0, 1.0)

Float() [2/2]

float Random::Float ( float  min, float  max  )

static

Generate a float in a given interval.

Parameters

min	the included lower bound
max	the excluded higher bound

Returns

a float in [min, max)

getSeed()

unsigned int Random::getSeed ( )

static

Query the current global seed.

Returns

the current global seed

Int()

int Random::Int ( int  min, int  max  )

static

Generate an integer in a given interval.

Parameters

min	the included lower bound
max	the included higher bound

Returns

an integer in [min, max]

sampleCosineHemisphere()

glm::vec3 Random::sampleCosineHemisphere ( )

static

Sample point from the hemisphere, following a cosine lobe

Returns

a 3D point on the unit z-positive hemisphere

sampleDisk()

glm::vec2 Random::sampleDisk ( )

static

Sample point uniformly on a disk.

Returns

a 2D point on the unit disk

sampleSphere()

glm::vec3 Random::sampleSphere ( )

static

Sample point uniformly on a sphere.

Returns

a 3D point on the unit sphere

seed() [1/2]

void Random::seed ( )

static

Seed the shared generator using a random number.

Note

The seed is obtained through a std::random_device.

Warning

Threads created before the call won't be seeded (except for the calling thread).

Note

It is recommended to seed the generator on the main thread at the beginning of the application execution.

seed() [2/2]

void Random::seed ( unsigned int  seedValue )

static

Seed the shared generator using a given number.

Parameters

seedValue

the seed to use

Warning

Threads created before the call won't be seeded (except for the calling thread).

Note

It is recommended to seed the generator on the main thread at the beginning of the application execution.

shuffle()

template<typename T >

void Random::shuffle ( std::vector< T > &  items )

static

Shuffle elements of a vector randomly, in-place.

Parameters

items

the items to shuffle

Member Data Documentation

_shared

std::mt19937 Random::_shared

staticprivate

Shared randomness generator, used for seeding per-thread generators.

Warning

Not thread safe.

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

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