MaxPhysics Community Project : Main

The Collition detection with a Line
If you put in the above John's example those two functions

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''''''	COLLIDE WITH LINE
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Function Collide:TList(Constraints:TList , x1:Float , y1:Float , x2:Float , y2:Float )
	Local ConList:TList = Null
	If Constraints <> Null
		For Local Constraint:VerletConstraint = EachIn Constraints 
			Local x3:Float = Constraint.ParticleA.x
			Local y3:Float = Constraint.ParticleA.y
			Local x4:Float = Constraint.ParticleB.x
			Local y4:Float = Constraint.ParticleB.y
			Local A:Double =  (y4 - y3)*(x2 - x1) - (x4 - x3)*(y2 - y1)
			
			If Not A = 0
				Local ua:Float = ( (x4 - x3)*(y1 - y3) - (y4 - y3)*(x1 - x3) ) /  A 
				Local ub:Float = ( (x2 - x1)*(y1 - y3) - (y2 - y1)*(x1 - x3) ) /  A 
				If ua >=0 And ua <=1 
					If ub >=0 And ub <=1 
						If ConList = Null 
							ConList = CreateList()
						End If
						Local P:Vector2d =  Point( x1 + ua*(x2 - x1) ,  y1 + ua*(y2 - y1) )
						ListAddLast ConList, P
						
					EndIf
				Endif
			EndIf
		Next
	End If
	Return ConList
End Function

Function Test(Constraints:TList)
	Local x1:Float = 20
	Local y1:Float = 20
	Local x2:Float = 400
	Local y2:Float = 400
	SetColor 255 , 0 , 0
	DrawLine x1 , y1 , x2 , y2
	Local CP:TList = Collide(Constraints , x1 , y1 , x2 , y2)
	If CP <> Null
		DrawText "Collide" , 20 , 20
	End If
End Function

At the begining of the example

import "Vector2d.Bmx"

And before the flip 1

	Test(Physics.Constraints)	

You have a visual of a basic collision detection
Also the collide function returns a TList with all the intersection points.

IMPORTANT : This is not coming from a tutorial so the whole idea may become a failure.
If you have any suggestion pls post

Also If anyone ever worked with collision stuff pls post