text: 
  function ScrollControls( camera , params ){
  
    this.camera     = camera;
    var params      = params || {};
  
    this.dampening  = params.dampening  || .9;
    this.minPos     = params.minPos     || -1000;
    this.maxPos     = params.maxPos     ||  0; 
    this.multiplier = params.multiplier || .01;
  
    this.speed = 0;
    
  
  
    window.addEventListener( 'mousewheel', this.onMouseWheel.bind( this ), false );
  
  
  }
  
  ScrollControls.prototype.update = function(){
  
    this.camera.position.y += this.speed;
  
    if( this.camera.position.y < this.minPos ){
  
      var dif = this.minPos - this.camera.position.y;
  
      this.camera.position.y = this.minPos;
      this.speed = 0;
     
      // this.speed += this.
  
    }else if( this.camera.position.y > this.maxPos ){
  
      var dif = this.maxPos - this.camera.position.y;
  
      this.camera.position.y = this.maxPos;
      this.speed = 0;
     
      // this.speed += this.
  
    }
  
    this.speed *= this.dampening;
  
  }
  
  
  ScrollControls.prototype.onMouseWheel = function( e ){
  
    this.speed += e.wheelDeltaY * this.multiplier; 
  
  }
  