Leap_JavaScript_API_trigger_point.html

<!DOCTYPE html>
<html>
<head>
<title>Leap JavaScript API</title>
<script>
var ws;
    
if ((typeof(WebSocket) == 'undefined') &&
    (typeof(MozWebSocket) != 'undefined')) {
  WebSocket = MozWebSocket;
}
    

function init() {
  ws = new WebSocket("ws://localhost:6437/");
  ws.onopen = function(event) {
    document.getElementById("main").style.visibility = "visible";
    document.getElementById("connection").innerHTML = "WebSocket connection open!";
  };
    
    
  var actionStartTime = new Date().getTime();
  var timeThreshold = 300;
    
  // is gun ready to be fired?
  var cocked;

  // co-ordinate corrections for converting tip positon to canvas position
  // where canvas top left corner is at (0,0)
  // finger tip position at left of range of motion is approx -230
  // finger tip position at right of range of motion is approx +230
  var XCORRECTION = 230;  // to be added to tip x position (position[0])
  // tip position at top of range of motion is approx 480
  // tip position at bottom of range of motion is approx 80
  var YCORRECTION = 480;  // to be substracted from tip y position (position[1])
    
    
    
  ws.onmessage = function(event) {
    var obj = JSON.parse(event.data);
    var str = JSON.stringify(obj, undefined, 2);
      
    var posX = XCORRECTION + Math.floor( obj.hands[0].fingers[0].tip.position[0]);
    var posY = YCORRECTION - Math.floor( obj.hands[0].fingers[0].tip.position[1]);
    document.getElementById("output").innerHTML = '<pre>' + "posX:"+ posX + " posY:" + posY+ '</pre>';

      
    // gun fires when finger count goes from cocked position (2 fingers) to 1 finger.
    var fingercount = obj.hands[0].fingers.length;        
    if (fingercount == 2) {
      cocked = 1; // 1 == true
    } else if (fingercount == 1) {
      if (cocked) {
          // shot fired!
          console.log("shot fired at", posX, posY);
      }
      cocked = 0; // 0 == false
    } else {
      cocked = 0; // 0 == false
    }
  };
    
  ws.onclose = function(event) {
    ws = null;
    document.getElementById("main").style.visibility = "hidden";
    document.getElementById("connection").innerHTML = "WebSocket connection closed";
  };
  ws.onerror = function(event) {
    alert("Received error");
  };
}
</script>
</head>
<body onload="init();">
<h1>Leap JavaScript API</h1>
<div id="connection">WebSocket not connected</div>
<div id="main" style="visibility:hidden">
  <p>Frame data:</p>
  <div id="output"></div>
</div>
</body>
</html>