108 lines
3.1 KiB
Lua
108 lines
3.1 KiB
Lua
--- Various utility functions
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-- @module utils
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local utils = {}
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-- reimplementation of math.frexp, due to its removal from Lua 5.3 :(
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-- courtesy of airstruck
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local log2 = math.log(2)
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local frexp = math.frexp or function(x)
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if x == 0 then return 0, 0 end
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local e = math.floor(math.log(math.abs(x)) / log2 + 1)
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return x / 2 ^ e, e
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end
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--- Clamps a value within the specified range.
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-- @param value Input value
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-- @param min Minimum output value
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-- @param max Maximum output value
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-- @return number
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function utils.clamp(value, min, max)
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return math.max(math.min(value, max), min)
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end
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--- Returns `value` if it is equal or greater than |`size`|, or 0.
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-- @param value
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-- @param size
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-- @return number
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function utils.deadzone(value, size)
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return math.abs(value) >= size and value or 0
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end
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--- Check if value is equal or greater than threshold.
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-- @param value
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-- @param threshold
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-- @return boolean
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function utils.threshold(value, threshold)
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-- I know, it barely saves any typing at all.
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return math.abs(value) >= threshold
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end
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--- Scales a value from one range to another.
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-- @param value Input value
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-- @param min_in Minimum input value
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-- @param max_in Maximum input value
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-- @param min_out Minimum output value
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-- @param max_out Maximum output value
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-- @return number
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function utils.map(value, min_in, max_in, min_out, max_out)
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return ((value) - (min_in)) * ((max_out) - (min_out)) / ((max_in) - (min_in)) + (min_out)
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end
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--- Linear interpolation.
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-- Performs linear interpolation between 0 and 1 when `low` < `progress` < `high`.
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-- @param progress (0-1)
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-- @param low value to return when `progress` is 0
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-- @param high value to return when `progress` is 1
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-- @return number
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function utils.lerp(progress, low, high)
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return progress * (high - low) + low
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end
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--- Hermite interpolation.
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-- Performs smooth Hermite interpolation between 0 and 1 when `low` < `progress` < `high`.
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-- @param progress (0-1)
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-- @param low value to return when `progress` is 0
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-- @param high value to return when `progress` is 1
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-- @return number
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function utils.smoothstep(progress, low, high)
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local t = utils.clamp((progress - low) / (high - low), 0.0, 1.0)
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return t * t * (3.0 - 2.0 * t)
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end
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--- Round number at a given precision.
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-- Truncates `value` at `precision` points after the decimal (whole number if
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-- left unspecified).
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-- @param value
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-- @param precision
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-- @return number
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function utils.round(value, precision)
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if precision then return utils.round(value / precision) * precision end
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return value >= 0 and math.floor(value+0.5) or math.ceil(value-0.5)
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end
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--- Wrap `value` around if it exceeds `limit`.
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-- @param value
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-- @param limit
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-- @return number
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function utils.wrap(value, limit)
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if value < 0 then
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value = value + utils.round(((-value/limit)+1))*limit
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end
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return value % limit
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end
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--- Check if a value is a power-of-two.
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-- Returns true if a number is a valid power-of-two, otherwise false.
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-- @author undef
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-- @param value
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-- @return boolean
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function utils.is_pot(value)
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-- found here: https://love2d.org/forums/viewtopic.php?p=182219#p182219
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-- check if a number is a power-of-two
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return (frexp(value)) == 0.5
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end
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return utils
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