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NumberUtil

The NumberUtil module provides utility functions for Lua numbers.

E

The irrational number e.

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NumberUtil.E == 2.7182818284590

Tau

Equal to 2π.

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NumberUtil.Tau == 6.2831853071796

Lerp(min, max, alpha)

Interpolate between two numbers by a certain alpha/percentage. The name "lerp" comes from combining linear interpolation.

Visually, think of a number line ranging from 'min' to 'max' and then move along that line by 'alpha' percent.

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NumberUtil.Lerp(5, 15, 0.5) == 10
NumberUtil.Lerp(5, 15, 0)   == 5
NumberUtil.Lerp(5, 15, 0.7) == 12
NumberUtil.Lerp(5, 15, 2)   == 25

LerpClamp(min, max, alpha)

The same as Lerp, except alpha is clamped between the range of [0, 1]. This helps avoid the resultant number being out of the input range of [min, max].

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NumberUtil.LerpClamp(5, 15, 0.5) == 10
NumberUtil.LerpClamp(5, 15, 2)   == 15  -- 'alpha' clamped to 1.

InverseLerp(min, max, num)

The inverse of the Lerp function. It returns the alpha value between the range of [min, max] given the num.

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NumberUtil.InverseLerp(5, 15, 10) == 0.5
NumberUtil.InverseLerp(5, 15, 12) == 0.7

Map(n, inMin, inMax, outMin, outMax)

Remaps the range of 'num' from its old range of [inMin, inMax] to a new range of [outMin, outMax]. This is useful when needing to convert a range of inputs to a different output. For instance, remapping gamepad stick input to a larger range controlling a vehicle steering wheel.

Mathematically, this is done by doing an inverse lerp with n on [inMin, inMax] to get the correct alpha value, and then lerping that alpha value with the range of [outMin, outMax].

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NumberUtil.Map(0.5, 0, 1, -10, 10) == 0
NumberUtil.Map(1, -1, 1, 0, 5)     == 5

Round(num)

Rounds a number to the nearest whole number.

Internally, this uses the math.floor and math.ceil Lua math functions to round the number.

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NumberUtil.Round(1.5)  == 2
NumberUtil.Round(3.2)  == 3
NumberUtil.Round(-0.5) == -1

RoundTo(num, multiple)

Rounds a number to the nearest given multiple. An example would be locking world positions onto a larger grid.

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NumberUtil.RoundTo(3.4, 5) == 5
NumberUtil.RoundTo(12, 5)  == 10