• Introduction

  • A 2D traffic map, & you can move an UnitObj in the Map from one Place to another (-- the Pathing Algorithm finds the way out).
  • (Pretty much like how you control the units in an RTS game.)

• Overview (graph)

  • 
  • TrafficSystem.20230609_003641.demo01_CrossBlock_Complex.mp4

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      <li>
    

    TrafficSystem.20230609_004856.demo02_AlignedCube_ComplexMoving_TrafficLight.mp4

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          <source src="images/TrafficSystem 20230609_004856 demo02_AlignedCube_ComplexMoving_TrafficLight.mp4" type="video/mp4">
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      <li>(Github md video support is very limited & its breaking the html code -- a li is added below to fix that)</li>
    

• Prior Clarification

  • This is only an Experimental project
    

• How To Use

  • Left click to select an UnitObj (for movable & selectable -- controllable ones)
  • Right click to move the UnitObj to that location

• Functionalities & Hotkeys

  • vv

    • Functionality	Hotkey	Description	Activated When	*
      select an UnitObj (for controllable ones)	LButton
      move an UnitObj to Target Location	RButton
      move an UnitObj to Multi Scheduled Target Locations	+RButton
      pause Movement of Selected UnitObj	s
      resume Movement of Selected UnitObj	e
      cancel Movement of Selected UnitObj	c
      select all UnitObj (for controllable ones)	^a
      unselect all UnitObj	MButton
      select multiple UnitObj	^LButton
      select on the Main UnitObj	!s
      drag an UnitObj (for draggable ones)	^!LButton (drag)
      clear Debug Shapes	!a

    • * annotate
      • Ahk Hotkey style Notation
        • ^ = Ctrl
        • ! = Alt
        • + = Shift
        • LButton = Left Mouse Click
  • vv
    • You can send a POST request to the TrafficController Service in Port 18091, eg:
    • http://localhost:18091/v0.2.1.0/user/createTrafficLight_demo_AlignedCube?sn_row_Target=2&sn_col_Target=1&timeLength_AllowMove=100&timeLength_StopMove=100&mode_VerticalOrHorizontal=false
    • (This in turn sends (delegates) a request (internally) to the TrafficPathing)
    • & creates a TrafficLight at the specified location (for the demo)

• Internal Design & Concept

  • Main Java class

    • PathingUtil is the central of the Pathing Algorithm
      • com.redfrog.traffic.pathing.PathingUtil.goTo_TargetLocation(UnitObj, double, double, double, GotoMode)
        is the main Api to use for Moving a (controllable) UnitObj to a Target Location
    • TrafficItemControlService is the central for creating the UnitObj (& the Map) (& Demo)

  • Algorithms

    • algorithm (function name)	success rate	time complexity	description	logic complexity
      (*some trivals)	5% (low) only works for simple shapes	O(1)		1%
      get_Points_AtCloserDirection_ByAreaDet	10% only works for simple shapes	O(1)		10%
      repath_by_WrapVertexSearchAlg _by_PermutationAndIntersection	100% works in all cases always finds the path (unless unreachable pratically) always finds the shortest path	~O(n!)	uses a Permutation to brute force all the possible paths (not just random brute force -- some level of logic is still required) takes very Long time to calculate -- when the shape is complex (optimization are added, made faster, but still not fast enough)	45%
      repath_by_WrapVertexSearchAlg _by_DirectionalTangentLine_with_ShortestGotoPoint	70% works in many cases sometimes fails to find a path (even such path exist pratically) often not finding the shortest path	~O(n)		50%
      repath_by_WrapVertexSearchAlg _by_DirectionalTangentLine_with_Permutation	95%~100% works in most/all cases always finds the path (should) may not find the shortest path	~O(n) ~O(n^2) ~O(n!)	(permutation is involved, a bit) (lots other nested sub algorithms / mechanisms are added for optimization)	65%

    • * the rate / complexity values are just rough estimations, no real math / benchmark

• Technology Stack

  • JavaFx
  • Spring

• Design Difficulties & Problems facing

  • Number Precision
    • double precision problem is a messy problem
    • in a Graphical app, precise Math calculations are required
      • eg: for the logic of Pathing Algorithm
      • eg: when you need to check for Collision
      • (tbh, this can apply to any other situations too...)
  • Collide & Stuck & Calc Hang & Both Dynamic
    • this happened many times (likey a bug)
    • I cannot tell where this is coming from:
      • inf loop/recursion;
      • some random bug (due to collision / determination of sth);
      • or there is no bug, but just the calculation is taking too long;
    • when there is only one UnitObj moving, the collision & pathing looks fine -- does not seem such bug
    • when there are 2 UnitObj moving -- especially when one of the UnitObj is doing unstoppable moving, the bug appears way more often
      • (-- if none are doing unstoppable moving -- seems fine)
  • Speed & Frame (& Incremental movements)
    • AnimationTimer is executing base on Frame, not Time.
    • This makes the calculation of Speed & detection of Collision harder.

• Q&A

  • Where is the Comment & JavaDoc?
    • The comments I had in the Code are hideously long & unreadable. So they are all removed.
      • (Hopefully this doesnt break the code, it shouldnt but might remove some actual code accidentally during the process.)