ffmap-backend/html/pacman.js

function pacman() {
  var angle = d3.scale.linear()
                    .domain([0, 1, 2, 3])
                    .range([0.01, Math.PI/4, 0.01, Math.PI/4])

  d3.timer(pacman_animate)
  var a = 0

  var p = {x: 0, y: 0}
  var pm = vis.append("path")
                  .style("fill", "#ff0")
                  .style("stroke", "#000")
                  .style("stroke-width", 2.5)
                  .style("stroke-linejoin", "round")

  function pacman_animate() {
    var size = force.size()
    var nodes = force.nodes()
    var n = nodes.length
    if (n == 0)
      return
   
    a = (a + 0.10)%2

    pm.attr("d", d3.svg.arc().innerRadius(0)
       .outerRadius(24).endAngle(-angle(a) + Math.PI/2 + 2*Math.PI).startAngle(angle(a) + Math.PI/2))

    var closest = null
    var dd = Infinity;
    for (i = 0; i < n; i++) {
      var o = nodes[i]

      var d = Math.pow((o.x - p.x),2) + Math.pow( o.y - p.y, 2)
      if (d < dd) {
        dd = d
        closest = o
      }
    }

    var dx = closest.x - p.x
    var dy = closest.y - p.y

    var d = Math.sqrt(Math.pow(dx,2) +  Math.pow(dy,2))

    dx = dx/d
    dy = dy/d

    if (d>8) {
      p.x += dx * 2
      p.y += dy * 6
    } else {
      var snd;
      if (closest.flags.client) {
        snd = new Audio("pacman_eatfruit.wav")
      } else {
        snd = new Audio("pacman_eatghost.wav")
      }
      snd.play()

      data.nodes = data.nodes.filter(function (d) {
        return d.id != closest.id
      })

      data.links = data.links.filter(function (d) {
        return d.target.id != closest.id && d.source.id != closest.id
      })
      update()
    }

    pm.attr("transform", "matrix(" + [dx, dy, -dy, dx, p.x, p.y].join(",") + ")")
  }
}