Collision Detection - Asteroids

'Class module
Sub Class_Globals
   Private MyRect As Rect
   Private Others As List
   Private checkInterval, interval As Int
   Private outRect(1) As Rect
   Private safeZone As Int
---->>   Public objectType As String    <<----
End Sub

Public Sub Initialize (vMyRect As Rect, vOthers As List, vCheckInterval As Int, vSafeZone As Int, vType As String)
   MyRect = vMyRect
   'Others is a list of objects. Each object should have a GetRect sub such as: 
   'Public Sub GetRect(outRect() As Rect)
   '   outRect(0) = bd.DestRect
   'End Sub
   'Note that this class holds a reference to the list. This means that if later an object is added or removed
   'then it will automatically affect this class as well.
   Others = vOthers
   'Check for collision every x ticks. If the objects do not move too fast there is no point
   'in checking for collision every tick.
   checkInterval = vCheckInterval
   'As each sprite is treated as a rectangle you may want to decrease the rectangle size to avoid cases
   'where the collision is in two corners for example.
   safeZone = vSafeZone
   'Define Object Type (car, dog, poop, etc.)
   objectType = vType
End Sub

'Checks for collisions. Returns the collided object if there was a collision
Public Sub Tick As Object
   interval = interval + 1
   If interval = checkInterval Then
      interval = 0
      Dim r As Rect
      For i = 0 To Others.Size - 1
         CallSub2(Others.Get(i), "GetRect", outRect)
         If MyRect.Left < outRect(0).Right - safeZone AND MyRect.Right > outRect(0).Left + safeZone _
            AND MyRect.Top < outRect(0).Bottom - safeZone AND MyRect.Bottom > outRect(0).Top + safeZone Then
            Return Others.Get(i)
         End If
      Next
      Return Null
   End If
End Sub

   Dim objType As String
   objType = "dog"
   collision.Initialize(leroyBd.DestRect, game.Dogs, 10, 10 * GameUtils.scale, objType)
   objType = "car"
   collision.Initialize(leroyBd.DestRect, game.Cars, 10, 10 * GameUtils.scale, objType)

      Dim catchDog As Dog
      catchDog = collision.Tick
      If catchDog <> Null Then
         game.PlaySound(game.barkSFX, 1)
         game.score = game.score + 100
         game.myScoreBoard.AddScore(game.score)
         game.dogRemain = game.dogRemain - 1
         game.myScoreBoard.dogUpdate(game.dogRemain)
         catchDog.Explode
      End If
      
      Dim killLeroy As Car
      killLeroy = collision.Tick
      If killLeroy <> Null Then
         Crash
      End If