xiiRandom Class Reference

Copyright (c) Theophilus Eriata. All Rights Reserved. More...

#include <Random.h>

Public Member Functions
void	Initialize (xiiUInt64 uiSeed)
	Initializes the RNG with the given seed value. The value should not be zero.
void	InitializeFromCurrentTime ()
void	Save (xiiStreamWriter &inout_stream) const
	Serializes the current state.
void	Load (xiiStreamReader &inout_stream)
	Deserializes the current state.
xiiUInt32	UInt ()
	Returns a uint32 value, ie. ranging from 0 to (2 ^ 32) - 1.
xiiUInt32	UIntInRange (xiiUInt32 uiRange)
xiiUInt32	UInt32Index (xiiUInt32 uiArraySize, xiiUInt32 uiFallbackValue=xiiInvalidIndex)
xiiUInt16	UInt16Index (xiiUInt16 uiArraySize, xiiUInt16 uiFallbackValue=0xFFFF)
xiiInt32	IntMinMax (xiiInt32 iMinValue, xiiInt32 iMaxValue)
	Returns an int32 value in range [iMinValue ; iMaxValue].
XII_ALWAYS_INLINE bool	Bool ()
	Returns a boolean either being true or false.
XII_ALWAYS_INLINE double	DoubleZeroToOneExclusive ()
	Returns a value in range [0.0 ; 1.0), ie. including zero, but excluding one.
XII_ALWAYS_INLINE double	DoubleZeroToOneInclusive ()
	Returns a value in range [0.0 ; 1.0], ie. including zero and one.
double	DoubleMinMax (double fMinValue, double fMaxValue)
	Returns a double value in range [fMinValue ; fMaxValue].
double	DoubleVariance (double fValue, double fVariance)
	Returns a double value around fValue with a given variance (0 - 1 range).
double	DoubleVarianceAroundZero (double fAbsMaxValue)
	Returns a double value between [-fAbsMaxValue; +fAbsMaxValue] with a Gaussian distribution.
XII_ALWAYS_INLINE float	FloatZeroToOneExclusive ()
	Returns a value in range [0.0 ; 1.0), ie. including zero, but excluding one.
XII_ALWAYS_INLINE float	FloatZeroToOneInclusive ()
	Returns a value in range [0.0 ; 1.0], ie. including zero and one.
XII_ALWAYS_INLINE float	FloatMinMax (float fMinValue, float fMaxValue)
	Returns a float value in range [fMinValue ; fMaxValue].
XII_ALWAYS_INLINE float	FloatVariance (float fValue, float fVariance)
	Returns a float value around fValue with a given variance (0 - 1 range).
XII_ALWAYS_INLINE float	FloatVarianceAroundZero (float fAbsMaxValue)
	Returns a float value between [-fAbsMaxValue; +fAbsMaxValue] with a Gaussian distribution.

Detailed Description

Copyright (c) Theophilus Eriata. All Rights Reserved.

A random number generator. Currently uses the WELL512 algorithm.

Member Function Documentation

DoubleMinMax()

double xiiRandom::DoubleMinMax	(	double	fMinValue,
		double	fMaxValue )

Returns a double value in range [fMinValue ; fMaxValue].

Todo

Probably not correct

DoubleVariance()

double xiiRandom::DoubleVariance	(	double	fValue,
		double	fVariance )

Returns a double value around fValue with a given variance (0 - 1 range).

Todo

Test whether this is actually correct

DoubleVarianceAroundZero()

double xiiRandom::DoubleVarianceAroundZero

(

double

fAbsMaxValue

)

Returns a double value between [-fAbsMaxValue; +fAbsMaxValue] with a Gaussian distribution.

Todo

Test whether this is actually correct

InitializeFromCurrentTime()

void xiiRandom::InitializeFromCurrentTime

(

)

Initializes the RNG using current time stamp. Not very sophisticated, but good enough for things that do not need to be secure.

UInt16Index()

xiiUInt16 xiiRandom::UInt16Index	(	xiiUInt16	uiArraySize,
		xiiUInt16	uiFallbackValue = 0xFFFF )

Returns a random uint16 in range [0 ; uiArraySize - 1].

Same as UInt32Index() just for 16 bit indices.

UInt32Index()

xiiUInt32 xiiRandom::UInt32Index	(	xiiUInt32	uiArraySize,
		xiiUInt32	uiFallbackValue = xiiInvalidIndex )

Returns a random uint32 in range [0 ; uiArraySize - 1].

If uiArraySize is 0, uiFallbackValue is returned instead. This is meant for generating a random index into an array. If the array is empty, no valid index can be generated, however, instead of asserting, a dedicated invalid index is returned.

This function is nearly the same as UIntInRange(), except that that function asserts that uiRange is larger than 0.

UIntInRange()

xiiUInt32 xiiRandom::UIntInRange

(

xiiUInt32

uiRange

)

Returns a uint32 value in range [0 ; uiRange - 1]

Note

A range of 0 is invalid and will assert! It also has no mathematical meaning. A range of 1 already means "between 0 and 1 EXCLUDING 1". So always use a range of at least 1.

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

• /home/runner/work/XII/XII/Source/Engine/Foundation/Math/Random.h
• /home/runner/work/XII/XII/Source/Engine/Foundation/Math/Implementation/Random.cpp