WoWInterface/Interface/AddOns/Plater/libs/DF/math.lua

local DF = _G ["DetailsFramework"]
if (not DF or not DetailsFrameworkCanLoad) then
	return 
end

local UnitExists = UnitExists
local atan2 = math.atan2
local pi = math.pi
local abs = math.abs 

SMALL_FLOAT = 0.000001

--find distance between two players
function DF:GetDistance_Unit (unit1, unit2)
	if (UnitExists (unit1) and UnitExists (unit2)) then
		local u1X, u1Y = UnitPosition (unit1)
		local u2X, u2Y = UnitPosition (unit2)
		
		local dX = u2X - u1X
		local dY = u2Y - u1Y
		
		return ((dX*dX) + (dY*dY)) ^ .5
	end
	return 0
end

--find distance between two points
function DF:GetDistance_Point (x1, y1, x2, y2)
	local dx = x2 - x1
	local dy = y2 - y1
	return ((dx * dx) + (dy * dy)) ^ .5
end

--find a rotation for an object from a point to another point
function DF:FindLookAtRotation (x1, y1, x2, y2)
	return atan2 (y2 - y1, x2 - x1) + pi
end

--find the value scale between two given values. e.g: value of 500 in a range 0-100 result in 10 in a scale for 0-10
function DF:MapRangeClamped (inputX, inputY, outputX, outputY, value)
	return DF:GetRangeValue (outputX, outputY, Clamp (DF:GetRangePercent (inputX, inputY, value), 0, 1))
end

--find the value scale between two given values. e.g: value of 75 in a range 0-100 result in 7.5 in a scale for 0-10
function DF:MapRangeUnclamped (inputX, inputY, outputX, outputY, value)
	return DF:GetRangeValue (outputX, outputY, DF:GetRangePercent (inputX, inputY, value))
end

--find the normalized percent of the value in the range. e.g range of 200-400 and a value of 250 result in 0.25
function DF:GetRangePercent (minValue, maxValue, value)
	return (value - minValue) / max((maxValue - minValue), SMALL_FLOAT)
end

--find the value in the range given from a normalized percent. e.g range of 200-400 and a percent of 0.8 result in 360
function DF:GetRangeValue (minValue, maxValue, percent)
	return Lerp (minValue, maxValue, percent)
end

--dot product of two 2D Vectors
function DF:GetDotProduct (value1, value2)
	return (value1.x * value2.x) + (value1.y * value2.y)
end

--normalized value 0-1 result in the value on the range given, e.g 200-400 range with a value of .5 result in 300
function DF:LerpNorm (minValue, maxValue, value)
	return (minValue + value * (maxValue - minValue))
end

--change the color by the deltaTime
function DF:LerpLinearColor (deltaTime, interpSpeed, r1, g1, b1, r2, g2, b2)
	deltaTime = deltaTime * interpSpeed
	local r = r1 + (r2 - r1) * deltaTime
	local g = g1 + (g2 - g1) * deltaTime
	local b = b1 + (b2 - b1) * deltaTime
	return r, g, b
end

--check if a number is near another number by a tolerance
function DF:IsNearlyEqual (value1, value2, tolerance)
	tolerance = tolerance or SMALL_FLOAT
	return abs (value1 - value2) <= tolerance
end

--check if a number is near zero
function DF:IsNearlyZero (value, tolerance)
	tolerance = tolerance or SMALL_FLOAT
	return abs (value) <= tolerance
end

--check if a number is within a two other numbers, if isInclusive is true, it'll  include the max value
function DF:IsWithin (minValue, maxValue, value, isInclusive)
	if (isInclusive) then
		return ((value >= minValue) and (value <= maxValue))	
	else
		return ((value >= minValue) and (value < maxValue))
	end
end

--dont allow a number ot be lower or bigger than a certain range
function DF:Clamp (minValue, maxValue, value)
	return value < minValue and minValue or value < maxValue and value or maxValue
end

--from http://lua-users.org/wiki/SimpleRound cut fractions on a float
function DF:Round (num, numDecimalPlaces)
	local mult = 10^(numDecimalPlaces or 0)
	return math.floor(num * mult + 0.5) / mult
end

function DF:ScaleBack ()

end