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vgstation13/code/__HELPERS/maths.dm
2015-08-18 17:29:27 +00:00

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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
/* //All point fingers and laugh at this joke of a list, I even heard using sqrt() is faster than this list lookup, honk.
// List of square roots for the numbers 1-100.
var/list/sqrtTable = list(1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 5,
5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10)
*/
/proc/Atan2(x, y)
if (!x && !y)
return 0
var/invcos = arccos(x / sqrt(x * x + y * y))
return y >= 0 ? invcos : -invcos
proc/arctan(x)
var/y=arcsin(x/sqrt(1+x*x))
return y
/proc/Ceiling(x, y = 1)
. = -round(-x / y) * y
//Moved to macros.dm to reduce pure calling overhead, this was being called shitloads, like, most calls of all procs.
/*
/proc/Clamp(const/val, const/min, const/max)
if (val <= min)
return min
if (val >= max)
return max
return val
*/
// cotangent
/proc/Cot(x)
return 1 / Tan(x)
// cosecant
/proc/Csc(x)
return 1 / sin(x)
/proc/Default(a, b)
return a ? a : b
/proc/Floor(x = 0, y = 0)
if(x == 0)
return 0
if(y == 0)
return round(x)
if(x < y)
return 0
var/diff = round(x, y) //finds x to the nearest value of y
if(diff > x)
return x - (y - (diff - x)) //diff minus x is the inverse of what we want to remove, so we subtract from y - the base unit - and subtract the result
else
return diff //this is good enough
// Greatest Common Divisor - Euclid's algorithm
/proc/Gcd(a, b)
return b ? Gcd(b, a % b) : a
/proc/Inverse(x)
return 1 / x
/proc/IsAboutEqual(a, b, deviation = 0.1)
return abs(a - b) <= deviation
/proc/IsEven(x)
return x % 2 == 0
// Returns true if val is from min to max, inclusive.
/proc/IsInRange(val, min, max)
return min <= val && val <= max
/proc/IsInteger(x)
return Floor(x) == x
/proc/IsOdd(x)
return !IsEven(x)
/proc/IsMultiple(x, y)
return x % y == 0
// Least Common Multiple
/proc/Lcm(a, b)
return abs(a) / Gcd(a, b) * abs(b)
// 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
/*
* Returns the nth root of x.
*/
/proc/Root(const/n, const/x)
return x ** (1 / n)
/*
* Secant.
*/
/proc/Sec(const/x)
return 1 / cos(x)
// 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
/*
* Tangent.
*/
/proc/Tan(const/x)
return sin(x) / cos(x)
/proc/ToDegrees(const/radians)
// 180 / Pi
return radians * 57.2957795
/proc/ToRadians(const/degrees)
// Pi / 180
return degrees * 0.0174532925
// 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)
/*
* A very crude linear approximatiaon of pythagoras theorem.
*/
/proc/cheap_pythag(const/Ax, const/Ay)
var/dx = abs(Ax)
var/dy = abs(Ay)
if (dx >= dy)
return dx + (0.5 * dy) // The longest side add half the shortest side approximates the hypotenuse.
else
return dy + (0.5 * dx)
/*
* Magic constants obtained by using linear regression on right-angled triangles of sides 0<x<1, 0<y<1
* They should approximate pythagoras theorem well enough for our needs.
*/
#define k1 0.934
#define k2 0.427
/proc/cheap_hypotenuse(const/Ax, const/Ay, const/Bx, const/By)
var/dx = abs(Ax - Bx) // Sides of right-angled triangle.
var/dy = abs(Ay - By)
if (dx >= dy)
return (k1*dx) + (k2*dy) // No sqrt or powers :).
else
return (k2*dx) + (k1*dy)
#undef k1
#undef k2
//Checks if something's a power of 2, to check bitflags.
//Thanks to wwjnc for this.
/proc/test_bitflag(var/bitflag)
return bitflag != 0 && !(bitflag & (bitflag - 1))