Reference TCollisionEvents

  TCollisionEvents = record
  public
    { Called when two shapes first touch. Return false to ignore the collision
      until they separate. }
    OnBegin: TCollisionFilterEvent;
    { Called each step while two shapes touch before the collision is solved.
      Return false to ignore the collision for this step. }
    OnPreSolve: TCollisionFilterEvent;
    { Called each step while two shapes touch after the collision is solved }
    OnPostSolve: TCollisionEvent;
    { Called when two shapes stop touching or one of them is removed }
    OnSeparate: TCollisionEvent;
  end;