distance formulas

Try this:

'iParXD = (iParX1 - iParX2)
'iParYD = (iParY1 - iParY2)
Function ApproxDistance:Int(iParXD:Int, iParYD:Int)
	Local iMin:Int
	Local iMax:Int
	
	If iParXD < 0 Then iParXD = -iParXD
	If iParYD < 0 Then iParYD = -iParYD
	If iParXD < iParYD Then
		iMin = iParXD
		iMax = iParYD
	Else
		iMin = iParYD
		iMax = iParXD
	EndIf
	
	Return (((iMax Shl 8) + (iMax Shl 3) - (iMax Shl 4) - (iMax Shl 1) + (iMin Shl 7) - (iMin Shl 5) + (iMin Shl 3) - (iMin Shl 1)) Shr 8)
End Function

Function Distance:Float(fParX1:Float, fParY1:Float, fParX2:Float = 0, fParY2:Float = 0)
	Return Sqr((fParX1 - fParX2) * (fParX1 - fParX2) + (fParY1 - fParY2) * (fParY1 - fParY2))
End Function

Function DistanceQuad:Float(fParX1:Float, fParY1:Float, fParX2:Float = 0, fParY2:Float = 0)
	Return ((fParX1 - fParX2) * (fParX1 - fParX2) + (fParY1 - fParY2) * (fParY1 - fParY2))
End Function

Function IntDistance:Int(iParX1:Int, iParY1:Int, iParX2:Int = 0, iParY2:Int = 0)
	Return Sqr((iParX1 - iParX2) * (iParX1 - iParX2) + (iParY1 - iParY2) * (iParY1 - iParY2))
End Function

Function IntDistanceQuad:Int(iParX1:Int, iParY1:Int, iParX2:Int = 0, iParY2:Int = 0)
	Return ((iParX1 - iParX2) * (iParX1 - iParX2) + (iParY1 - iParY2) * (iParY1 - iParY2))
End Function

The Int-Functions are a little faster than the Float-Ones, also the Quad-Ones are really fast compared to the Non-Quad-ones. But, keep in Mind: If you use the Int-Version, it'll give you an overflow if the quad of the distance is higher than Int can handle.

The fastest Distance-Approximation I've seen so far is the ApproxDistance-Function above. Really really fast.