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Paradise/code/__HELPERS/maths.dm
2016-05-06 04:38:59 -04:00

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// Credits to Nickr5 for the useful procs I've taken from his library resource.
var/const/E = 2.71828183
var/const/Sqrt2 = 1.41421356
/proc/Atan2(x, y)
if(!x && !y) return 0
var/a = arccos(x / sqrt(x*x + y*y))
return y >= 0 ? a : -a
// Greatest Common Divisor - Euclid's algorithm
/proc/Gcd(a, b)
return b ? Gcd(b, a % b) : a
/proc/IsAboutEqual(a, b, deviation = 0.1)
return abs(a - b) <= deviation
// Performs a linear interpolation between a and b.
// Note that amount=0 returns a, amount=1 returns b, and
// amount=0.5 returns the mean of a and b.
/proc/Lerp(a, b, amount = 0.5)
return a + (b - a) * amount
/proc/Mean(...)
var/values = 0
var/sum = 0
for(var/val in args)
values++
sum += val
return sum / values
// The quadratic formula. Returns a list with the solutions, or an empty list
// if they are imaginary.
/proc/SolveQuadratic(a, b, c)
ASSERT(a)
. = list()
var/d = b*b - 4 * a * c
var/bottom = 2 * a
if(d < 0) return
var/root = sqrt(d)
. += (-b + root) / bottom
if(!d) return
. += (-b - root) / bottom
// Will filter out extra rotations and negative rotations
// E.g: 540 becomes 180. -180 becomes 180.
/proc/SimplifyDegrees(degrees)
degrees = degrees % 360
if(degrees < 0)
degrees += 360
return degrees
// min is inclusive, max is exclusive
/proc/Wrap(val, min, max)
var/d = max - min
var/t = Floor((val - min) / d)
return val - (t * d)
/proc/RaiseToPower(num, power)
if(!power) return 1
return (power-- > 1 ? num * RaiseToPower(num, power) : num)
//converts a uniform distributed random number into a normal distributed one
//since this method produces two random numbers, one is saved for subsequent calls
//(making the cost negligble for every second call)
//This will return +/- decimals, situated about mean with standard deviation stddev
//68% chance that the number is within 1stddev
//95% chance that the number is within 2stddev
//98% chance that the number is within 3stddev...etc
var/gaussian_next
#define ACCURACY 10000
/proc/gaussian(mean, stddev)
var/R1;var/R2;var/working
if(gaussian_next != null)
R1 = gaussian_next
gaussian_next = null
else
do
R1 = rand(-ACCURACY,ACCURACY)/ACCURACY
R2 = rand(-ACCURACY,ACCURACY)/ACCURACY
working = R1*R1 + R2*R2
while(working >= 1 || working==0)
working = sqrt(-2 * log(working) / working)
R1 *= working
gaussian_next = R2 * working
return (mean + stddev * R1)
#undef ACCURACY