flock.html

<html>
  <head>
    <title>Flock Model</title>
    <script src="../lib/agentscript.js"></script>
    <script src="../tools/coffee-script.js"></script>
    <script type="text/coffeescript">

    u = ABM.Util # Aliases
    Shapes = ABM.Shapes
    class MyModel extends ABM.Model

      setVision: (@vision) ->  @patches.cacheRect @vision, true
      setMaxTurn: (maxTurn) -> @maxTurn = u.degToRad(maxTurn)
      toggleConsole: () -> @useConsole = not @useConsole

      setup: ->
        # u.randomSeed() # use for repeatable runs

        @refreshPatches = false # <3fps->4fps turtles larger part of drawing
        # No optimizations: 4fps
        # @patches.usePixels() # 4fps same as refresh off
        @patches.cacheTurtlesHere() # 17fps, big help for inRadius

        # w/ refresh off and two optimizations, 22-23fps
        # Deprecated:
        # @turtles.setUseSprites() # 24 -> 36

        @turtles.setDefault "useSprites", true
        @anim.setRate 60# , false, false # multistep, noRAF

        @useConsole = true
        @population = 150     # turtles (was more, Chrome regression problem)
        @setVision 3          # patches & set patch rect
        @minSeparation = 0.75 # patches
        @setMaxTurn(3.0)      # degrees -> radians

        # defaults
        @turtles.setDefault "size", 1.5
        # @turtles.setDefault "color", [255,0,0] # slightly faster! ->38/39 ??

        p.color = u.randomGray 0, 100 for p in @patches
        p.sprout 1 for p in @patches.nOf(@population)
        #a.color = u.randomMapColor() for a in @turtles

      step: ->
        if @useConsole and @anim.ticks % 100 is 0
          console.log "flock alignment: #{@reportFlockVectorSize()}"
        @flock(a) for a in @turtles

      flock: (a) -> # a is turtle
        # These two forms are identical
        # flockmates = @turtles.inRadius(a, @vision).other(a)
        flockmates = a.inRadius(@turtles, @vision).other(a)
        if flockmates.length isnt 0
          [nearestNeighbor, d] = u.minOneOf flockmates, ((f) -> f.distance a), true
          if d < @minSeparation
            @separate a, nearestNeighbor
          else
            @align a, flockmates
            @cohere a, flockmates
        a.forward .5 # move partial patch for smooth animation.

      separate: (a, nearest) ->
        h = nearest.towards a; @turnTowards a, h
      align: (a, flockmates) ->
        @turnTowards a, @averageHeading(flockmates)
      cohere: (a, flockmates) ->
        @turnTowards a, @averageHeadingTowards(a, flockmates)

      turnTowards: (a, heading) ->
        turn = u.subtractRads heading, a.heading # angle from h to a
        turn = u.clamp turn, -@maxTurn, @maxTurn # limit the turn
        a.rotate turn
      averageHeading: (flockmates) ->
        dx = (Math.sin f.heading for f in flockmates).reduce (x,y) -> x+y
        dy = (Math.cos f.heading for f in flockmates).reduce (x,y) -> x+y
        @safeAtan dy, dx
      averageHeadingTowards: (a, flockmates) ->
        dx = (Math.sin f.towards a for f in flockmates).reduce (x,y) -> x+y
        dy = (Math.cos f.towards a for f in flockmates).reduce (x,y) -> x+y
        @safeAtan dy, dx
      safeAtan: (x,y) -> Math.atan2 y, x # if x is 0 and y is 0 then 0 else Math.atan2 y, x # atan ok if x 0

      reportFlockVectorSize: ->
        dx = (Math.sin a.heading for a in @turtles).reduce (x,y) -> x+y
        dy = (Math.cos a.heading for a in @turtles).reduce (x,y) -> x+y
        Math.sqrt(dx*dx + dy*dy)/@population

    # div, patchSize, minX, maxX, minY, maxY, isTorus, hasNeighbors
    #   Defaults: 13, -16, 16, -16, 16, false, true
    model = new MyModel({
      div: "layers",
      size: 15,
      minX: -16,
      maxX: 16,
      minY: -16,
      maxY: 16,
      isTorus: true,
      hasNeighbors: false
    })
    .debug() # Debug: Put Model vars in global name space
    .start() # Run model immediately after startup initialization

    </script>
  </head>
  <body>
    <div id="layers"></div>
  </body>
</html>