81 lines
No EOL
2.8 KiB
Lua
81 lines
No EOL
2.8 KiB
Lua
-- randomize input
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function math.variance(seed, variance)
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return seed * ((math.random( 100 - (variance/2), 100 + (variance/2)))/100)
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end
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--Returns the x vector from {len} and {dir}
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function math.lengthdir_x( len, dir )
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local dir = math.rad( dir )
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return math.cos( dir ) * len
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end
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--Returns the y vector from {len} and {dir}
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function math.lengthdir_y( len, dir )
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local dir = math.rad( dir )
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return -math.sin( dir ) * len
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end
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-- Averages an arbitrary number of angles (in radians).
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function math.averageAngles(...)
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local x,y = 0,0
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for i=1,select('#',...) do local a= select(i,...) x, y = x+math.cos(a), y+math.sin(a) end
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return math.atan2(y, x)
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end
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-- Returns the distance between two points.
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function math.dist(x1,y1, x2,y2) return ((x2-x1)^2+(y2-y1)^2)^0.5 end
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-- Returns the angle between two points.
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function math.angle(x1,y1, x2,y2) return math.atan2(x2-x1, y2-y1) end
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-- Returns the closest multiple of 'size' (defaulting to 10).
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function math.multiple(n, size) size = size or 10 return math.round(n/size)*size end
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-- Clamps a number to within a certain range.
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function math.clamp(low, n, high) return math.min(math.max(low, n), high) end
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-- Linear interpolation between two numbers.
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function math.lerp(a,b,t) return a+(b-a)*t end
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-- Cosine interpolation between two numbers.
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function math.cerp(a,b,t) local f=(1-math.cos(t*math.pi))*.5 return a*(1-f)+b*f end
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-- Normalize two numbers.
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function math.normalize(x,y) local l=(x*x+y*y)^.5 if l==0 then return 0,0,0 else return x/l,y/l,l end end
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-- Returns 'n' rounded to the nearest 'deci'th (defaulting whole numbers).
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function math.round(n, deci) deci = 10^(deci or 0) return math.floor(n*deci+.5)/deci end
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-- Randomly returns either -1 or 1.
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function math.rsign() return math.random(2) == 2 and 1 or -1 end
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-- Returns 1 if number is positive, -1 if it's negative, or 0 if it's 0.
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function math.sign(n) return n>0 and 1 or n<0 and -1 or 0 end
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-- Checks if two lines intersect (or line segments if seg is true)
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-- Lines are given as four numbers (two coordinates)
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function findIntersect(l1p1x,l1p1y, l1p2x,l1p2y, l2p1x,l2p1y, l2p2x,l2p2y, seg1, seg2)
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local a1,b1,a2,b2 = l1p2y-l1p1y, l1p1x-l1p2x, l2p2y-l2p1y, l2p1x-l2p2x
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local c1,c2 = a1*l1p1x+b1*l1p1y, a2*l2p1x+b2*l2p1y
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local det,x,y = a1*b2 - a2*b1
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if det==0 then return false, "The lines are parallel." end
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x,y = (b2*c1-b1*c2)/det, (a1*c2-a2*c1)/det
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if seg1 or seg2 then
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local min,max = math.min, math.max
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if seg1 and not (min(l1p1x,l1p2x) <= x and x <= max(l1p1x,l1p2x) and min(l1p1y,l1p2y) <= y and y <= max(l1p1y,l1p2y)) or
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seg2 and not (min(l2p1x,l2p2x) <= x and x <= max(l2p1x,l2p2x) and min(l2p1y,l2p2y) <= y and y <= max(l2p1y,l2p2y)) then
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return false, "The lines don't intersect."
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end
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end
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return x,y
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end |