// JavaScript Document
// Original code by Evgeny Demidov
// http://www.ibiblio.org/e-notes/webgl/gpu/n-toy.html

var drag = 0;
var rxOffs = 0;
var ryOffs = 0;
var txOffs = 0;
var tyOffs = 0;
var tzOffs = 0;

var mouseXY = V3.$(-360,3,0);

function interact(){
  canvas.onmousedown = function ( ev ){
    drag  = 1;
    rxOffs = ev.clientX/100 - localParam.camera.rotate[1];
    ryOffs = ev.clientY/100 - localParam.camera.rotate[0];
    txOffs = +ev.clientX/10 - localParam.camera.translate[0];
    tyOffs = +ev.clientY/10 - localParam.camera.translate[1];
    tzOffs = +ev.clientY/10 +ev.clientX/10 - localParam.camera.translate[2];
  }
  canvas.onmouseup = function ( ev ){
    drag  = 0;
    rxOffs = ev.clientX/100;
    ryOffs = ev.clientY/100;
    txOffs = +ev.clientX/10;
    tyOffs = +ev.clientY/10;
    tzOffs = +ev.clientY/10 +ev.clientX/10;
  }
  canvas.onmousemove = function ( ev ){
  // mouseXY[0] = ev.clientX - docWidth/2;
 // mouseXY[1] = ev.clientY - docHeight/2;
  //    console.log(mouseXY[0]+','+mouseXY[1]);

   if ( drag == 0 ) return;
   if ( ev.altKey ) {
      localParam.camera.translate[2] = +ev.clientY/10 +ev.clientX/10 - tzOffs;}
   else if ( ev.shiftKey ) {
      localParam.camera.translate[0] = ev.clientX/10 - txOffs;
      localParam.camera.translate[1] = ev.clientY/10 - tyOffs;         
   } else {
      localParam.camera.rotate[1] = (ev.clientX/100 - rxOffs);
      localParam.camera.rotate[0] = (ev.clientY/100 - ryOffs);
   }
  }
}