var prevPrlxX = -1;
var prevPrlxY = -1;
var curPrlxX = -1;
var curPrlxY = -1;
function doMouseMove(evt)
{
  if (typeof(UseScroll) != "undefined")
    UseScroll.hide();

  try
  {
    curPrlxX = Math.floor((evt.clientX || evt.mouseX || 0)/document.body.offsetWidth*200)/100 - 1;
    curPrlxY = Math.floor((evt.clientY || evt.mouseY || 0)/document.body.offsetHeight*200)/100 - 1;

    if (curPrlxX != prevPrlxX)
    {
      gebid("tree1").style.left = Math.floor(0 - 20*(curPrlxX+1)) + "px";
      gebid("tree2").style.right = Math.floor(25 + 10*(curPrlxX+1)) + "px";
      gebid("gras").style.right = Math.floor(-40 + 10*(curPrlxX+1)) + "px";
      gebid("sky").firstChild.style.left = Math.floor(-20 + 10*(curPrlxX+1)) + "px";

      if (typeof(topics) != "undefined")
      {
        for (var i=0; i<topics.__allTopicEls.length; i++)
        {
          var el = topics.__allTopicEls[i];
          el.style.left = el.posLeft - 4*(el.scale-0.3)*curPrlxX + "%";
        }
      }

      prevPrlxX = curPrlxX;
    }

    if (curPrlxY != prevPrlxY)
    {
      gebid("tree1").style.top = Math.floor(0 - 20*(curPrlxY+1)) + "px";
      gebid("tree2").style.bottom = Math.floor(60 + 10*(curPrlxY+1)) + "px";
      gebid("gras").style.bottom = Math.floor(-20 + 10*(curPrlxY+1)) + "px";
      gebid("sky").firstChild.style.top = Math.floor(-20 + 10*(curPrlxY+1)) + "px";

      if (typeof(topics) != "undefined")
      {
        for (var i=0; i<topics.__allTopicEls.length; i++)
        {
          var el = topics.__allTopicEls[i];
          el.style.top = el.posTop - 4*(el.scale-0.3)*curPrlxY + "%";
        }
      }

      prevPrlxY = curPrlxY;
    }
  }
  catch(e)
  {
  }
}