modlib/math.lua
2021-03-04 12:19:08 +01:00

72 lines
2.0 KiB
Lua

-- Make random random
math.randomseed(minetest and minetest.get_us_time() or os.time() + os.clock())
for _ = 1, 100 do math.random() end
function round(number, steps)
steps = steps or 1
return math.floor(number * steps + 0.5) / steps
end
local c0 = ("0"):byte()
local cA = ("A"):byte()
function default_digit_function(digit)
if digit <= 9 then return string.char(c0 + digit) end
return string.char(cA + digit - 10)
end
default_precision = 10
-- See https://github.com/appgurueu/Luon/blob/master/index.js#L724
function tostring(number, base, digit_function, precision)
digit_function = digit_function or default_digit_function
precision = precision or default_precision
local out = {}
if number < 0 then
table.insert(out, "-")
number = -number
end
number = number + base ^ -precision / 2
local digit
while number >= base do
digit = math.floor(number % base)
table.insert(out, digit_function(digit))
number = number / base
end
digit = math.floor(number)
table.insert(out, digit_function(digit))
modlib.table.reverse(out)
number = number % 1
if number ~= 0 and number >= base ^ -precision then
table.insert(out, ".")
while precision >= 0 and number >= base ^ precision do
number = number * base
digit = math.floor(number % base)
table.insert(out, digit_function(digit))
number = number - digit
precision = precision - 1
end
end
return table.concat(out)
end
-- See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/fround#polyfill
function fround(number)
if number == 0 or number ~= number then
return number
end
local sign = 1
if number < 0 then
sign = -1
number = -number
end
local exp = math.floor(math.log(number, 2))
local powexp = 2 ^ math.max(-126, math.min(number, 127))
local leading = exp < -127 and 0 or 1
local mantissa = math.floor((leading - number / powexp) * 0x800000 + 0.5)
if mantissa <= -0x800000 then
return sign * math.huge
end
mantissa = mantissa / 0x800000
return sign * powexp * (leading - mantissa), mantissa
end