// Backwards compatibility.
mathx = math

/*---------------------------------------------------------
   Name: Deg2Rad( in )
   Desc: Convert degrees to radians
---------------------------------------------------------*/
function math.Deg2Rad( deg )
	return deg * ( math.pi / 180 )
end


/*---------------------------------------------------------
   Name: Rad2Deg( in )
   Desc: Convert radians to degrees
---------------------------------------------------------*/
function math.Rad2Deg( rad )
	return rad * ( 180 / math.pi )
end

/*---------------------------------------------------------
   Name: Dist( low, high )
   Desc: Distance between two 2d points
----------------------------------------------------------*/
function math.Dist( x1, y1, x2, y2 )
	local xd = x2-x1
	local yd = y2-y1
	return math.sqrt( xd*xd + yd*yd )
end

math.Distance = math.Dist // alias


/*---------------------------------------------------------
   Name: BinToInt( bin )
   Desc: Convert a binary string to an integer number
----------------------------------------------------------*/
function math.BinToInt(bin)
	return tonumber(bin,2)
end


/*---------------------------------------------------------
   Name: IntToBin( int )
   Desc: Convert an integer number to a binary string
----------------------------------------------------------*/
function math.IntToBin(int)

	local str = string.format("%o",int)

	local a = {
			["0"]="000",["1"]="001", ["2"]="010",["3"]="011",
        		["4"]="100",["5"]="101", ["6"]="110",["7"]="111"
		  }
	bin = string.gsub( str, "(.)", function ( d ) return a[ d ] end )
	return bin

end

/*---------------------------------------------------------
   Name: Clamp( in, low, high )
   Desc: Clamp value between 2 values
----------------------------------------------------------*/
function math.Clamp( _in, low, high )
	if (_in < low ) then return low end
	if (_in > high ) then return high end
	return _in
end

/*---------------------------------------------------------
   Name: Rand( low, high )
   Desc: Random number between low and high
---------------------------------------------------------*/
function math.Rand( low, high )
	return low + ( high - low ) * math.random()
end

/*---------------------------------------------------------
    math.Max, alias for math.max
---------------------------------------------------------*/
math.Max = math.max

/*---------------------------------------------------------
   math.Min, alias for math.min
---------------------------------------------------------*/
math.Min = math.min

/*---------------------------------------------------------
    Name: EaseInOut(fProgress, fEaseIn, fEaseOut)
    Desc: Provided by garry from the facewound source and converted
          to Lua by me :p
   Usage: math.EaseInOut(0.1, 0.5, 0.5) - all parameters shoule be between 0 and 1
---------------------------------------------------------*/
function math.EaseInOut( fProgress, fEaseIn, fEaseOut ) 

	if (fEaseIn == nil) then fEaseIn = 0 end
	if (fEaseOut == nil) then fEaseOut = 1 end

	local fSumEase = fEaseIn + fEaseOut; 

	if( fProgress == 0.0 || fProgress == 1.0 ) then return fProgress end

	if( fSumEase == 0.0 ) then return fProgress end
	if( fSumEase > 1.0 ) then
		fEaseIn = fEaseIn / fSumEase; 
		fEaseOut = fEaseOut / fSumEase; 
	end

	local fProgressCalc = 1.0 / (2.0 - fEaseIn - fEaseOut); 

	if( fProgress < fEaseIn ) then
		return ((fProgressCalc / fEaseIn) * fProgress * fProgress); 
	elseif( fProgress < 1.0 - fEaseOut ) then
		return (fProgressCalc * (2.0 * fProgress - fEaseIn)); 
	else 
		fProgress = 1.0 - fProgress; 
		return (1.0 - (fProgressCalc / fEaseOut) * fProgress * fProgress); 
	end
end


/*------------------------------------
	KNOT()
------------------------------------*/
local function KNOT( i, tinc )

	return ( i - 3 ) * tinc;
	
end


/*------------------------------------
	math.calcBSplineN()
------------------------------------*/
function math.calcBSplineN( i, k, t, tinc )

	if ( k == 1 ) then
	
		if ( ( KNOT( i, tinc ) <= t ) && ( t < KNOT( i + 1, tinc ) ) ) then
		
			return 1;
			
		else
		
			return 0;
			
		end
		
	else
		local ft = ( t - KNOT( i, tinc ) ) * math.calcBSplineN( i, k - 1, t, tinc );
		local fb = KNOT( i + k - 1, tinc ) - KNOT( i, tinc );

		local st = ( KNOT( i + k, tinc ) - t ) * math.calcBSplineN( i + 1, k - 1, t, tinc );
		local sb = KNOT( i + k, tinc ) - KNOT( i + 1, tinc );
		
		local first = 0;
		local second = 0;

		if ( fb > 0 ) then
		
			first = ft / fb;
			
		end
		if ( sb > 0 ) then
		
			second = st / sb;
			
		end

		return first + second;
		
	end
	
end


/*------------------------------------
	math.BSplinePoint()
------------------------------------*/
function math.BSplinePoint( tDiff, tPoints, tMax )
	
	local Q = Vector( 0, 0, 0 );
	local tinc = tMax / ( table.getn( tPoints ) - 3 );
	
	tDiff = tDiff + tinc;
	
	for idx, pt in pairs( tPoints ) do
	
		local n = math.calcBSplineN( idx, 4, tDiff, tinc );
		Q = Q + (n * pt);
		
	end
	
	return Q;
	
end



/*---------------------------------------------------------
    Name: Round( round )
---------------------------------------------------------*/
function math.Round(num, idp)

	local mult = 10^(idp or 0)
	return math.floor(num * mult + 0.5) / mult
  
end

/*---------------------------------------------------------
    Name: Approach( cur, target, inc )
---------------------------------------------------------*/
function math.Approach( cur, target, inc )

	inc = math.abs( inc )

	if (cur < target) then
		
		return math.Clamp( cur + inc, cur, target )

	elseif (cur > target) then

		return math.Clamp( cur - inc, target, cur )

	end

	return target
	
end

function math.NormalizeAngle( a )
	return ( a + 180 ) % 360 - 180
end


function math.AngleDifference( a, b )

	local diff = math.NormalizeAngle( a - b )
	
	if ( diff < 180 ) then
		return diff
	end
	
	return diff - 360

end

/*---------------------------------------------------------
    Name: ApproachAngle( cur, target, inc )
---------------------------------------------------------*/
function math.ApproachAngle( cur, target, inc )

	local diff = math.AngleDifference( target, cur )
	
	return math.Approach( cur, cur + diff, inc )
	
end

/*---------------------------------------------------------
    Name: TimeFraction( Start, End, Current )
---------------------------------------------------------*/
function math.TimeFraction( Start, End, Current )
	return ( Current - Start ) / ( End - Start )
end