agentscript/models/nbody.html at master · gepr/agentscript · GitHub

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

    u = ABM.Util # ABM.Util alias
    class MyModel extends ABM.Model
      setup: ->
        @refreshPatches = false # for static patches

        # globals
        @population = 4
        @sun = true
        @v0max = 1
        @gravExp = -2
        # use maxX/Ycor: turtle coords extend to +/-.5 further than maxX/Y.
        @maxDistanceFromSun = Math.sqrt(Math.pow(@world.maxYcor,2)+Math.pow(@world.maxXcor,2))

        # defaults
        @turtles.setDefault "shape", "circle"
        @turtles.setDefault "heading", 0 # override promotion to random angle

        # window.foo = @patches.nOf(@population)
        for p in @patches.nOf(@population)
          p.sprout 1, @turtles, (a) =>
            if @sun and a.id is 0
              a.mass = 10000; a.setXY 0,0; a.vx = a.vy = 0
            else
              a.mass = 10 + u.randomInt(1000)
              a.vx = @v0max * (1 - u.randomFloat(2))
              a.vy = @v0max * (1 - u.randomFloat(2))
              # a.penDown = true
            a.size = 3 * u.log10(a.mass)

        # @turtles.setDefaultPen(1, true)
        @turtles.setDefault "penSize", 1 #Pen(1, true)
        @turtles.setDefault "penDown", true #Pen(1, true)
      step: ->
        # console.log @anim.toString() if @anim.ticks % 100 is 0
        for a in @turtles
          for a1 in @turtles.other(a)
            k = Math.pow(10, @gravExp)*a1.mass/Math.max(Math.pow(a.distance(a1),3), .000001)
            a.vx += (a1.x-a.x)*k; a.vy += (a1.y-a.y)*k
        for a in @turtles when not (@sun? and a.id is 0)
          # unless (@sun and a.id is 0)
          # scale opacity by distance to center
          opacityScale = (1-a.distance(@patches.patch(0,0))/@maxDistanceFromSun)
          # Lots of ways to scale opacity:
          # - Build an opacity gradient (ColorMaps) for each planet
          # - Create a new color w/ the new opacity/alpha
          # - Set the color's r,g,b,a via setter or property name
          [r, g, b] = a.color # first, get my r,g,b,a values
          # safe to add 10, will clip when expression > 255
          # a.color = [r, g, b, (10+opacityScale*255)]
          a.setColor r, g, b, (10+opacityScale*255) # way less GC
          # console.log opacityScale if a.id is 2
          # a.color = a.color
          # a.scaleOpacity a.color.slice(0,3), opacityScale
          #
          a.setXY u.clamp(a.x+a.vx, @patches.minX, @patches.maxX),
                  u.clamp(a.y+a.vy, @patches.minY, @patches.maxY)
          a.vx = u.sign(-a.x)*.001 if Math.abs(a.x) is @patches.maxX
          a.vy = u.sign(-a.y)*.001 if Math.abs(a.y) is @patches.maxY
          # # a.setXY 0,0 if @sun and a.id is 0
        null

    # div, patchSize, minX, maxX, minY, maxY, isTorus, hasNeighbors
    #   Defaults: 13, -16, 16, -16, 16, false, true
    model = new MyModel {
      div: "layers",
      size: 2,
      minX: -120,
      maxX: 120,
      minY: -100,
      maxY: 100,
      hasNeighbors: false
    }
    model.debug() # Debug: Put Model vars in global name space
    model.start() # Run model immediately after startup initialization

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