Option Explicit
'Script written by Howard Jiho Kim / crtl-i.com

Call Main()
Sub Main()
		
	Dim startPt, velocity
	velocity = Array(10,0,0)
	startPt = Rhino.GetObjects("Select Start Points",1)
	
	'Attractors / Distances
	Dim no_attr, attr, attrStr, i
	no_attr = Rhino.GetInteger("How many attractors?")
	ReDim attr(no_attr-1), attrStr(no_attr-1)
	
	For i=0 To no_attr-1
		attr(i) = Rhino.GetObject("Select Attractor " & (i+1),1)
		attrStr(i) = Rhino.GetReal("Enter Strength for Attractor " & (i+1))
	Next
	
	For i=0 To Ubound(startPt)
		Flow velocity, startPt(i), no_attr, attr, attrStr, 35
	Next
	
	
End Sub
Function Flow(velocity, startPt, no_attr, attr, attrStr, gens)
	
	Dim vec1, vec0
	vec1 = Rhino.VectorCreate(velocity, Array(0,0,0))
	vec0 = Rhino.VectorCreate(Rhino.PointCoordinates(startPt), Array(0,0,0))
	
	Dim totalDistance, distance, i
	ReDim distance(no_attr-1)
	
	Dim vec, finalVec, vec4, tagStop
	tagStop = 0
	ReDim vec(no_attr-1)
	
	Dim newPt, newLine, endPt2
	totalDistance=0
	

	
	If gens>0 Then
		
		For i=0 To no_attr-1
			distance(i) = Rhino.Distance(Rhino.PointCoordinates(startPt), Rhino.PointCoordinates(attr(i)))
			totalDistance = totalDistance + distance(i)
			Rhino.Print distance(i)
			Rhino.Print totalDistance
			If distance(i) < 1 Then
				gens = -1
			End If
		Next
	
		'Vectors
	
		vec4 = vec1
		
		For i=0 To no_attr-1
			vec(i) = Rhino.VectorCreate(Rhino.PointCoordinates(attr(i)), Rhino.PointCoordinates(startPt))
			vec(i) = Rhino.VectorUnitize(vec(i))
			vec(i) = Rhino.VectorScale(vec(i), (attrStr(i)/distance(i))^2)
		
			vec4 = Rhino.VectorAdd(vec4, vec(i))
		Next
		
		finalVec = Rhino.VectorUnitize(vec4)
		finalVec = Rhino.VectorScale(finalVec, 1)
		
		If tagStop = 0 Then
			newPt = Rhino.AddPoint(finalVec)
			newLine = Rhino.AddLine(Array(0,0,0), finalVec)
			endPt2 = Rhino.MoveObject(newPt, vec0)
			newLine = Rhino.MoveObject(newLine, vec0)
		End If
		
		Flow velocity, endPt2, no_attr, attr, attrStr, gens-1
		
	End If
	
End Function