// 绕当前视点旋转
RotControl = function ( camera, div) {

	var self = this;
	var $div = $(div);
	camera.target = new THREE.Vector3( 0, 0, 0 );
	
	// 事件，回调函数
	this.onRot = function(event){
	}
	
	var limit = Math.PI *3/ 4;	


	var first = true;
	var drag = false;
	var lastX=0;
	var lastY=0;
	var lastDist=0;
	
	
	
	// touch消息里没有offseXY数值，我得想办法从其他数值计算出来
	// 以前我记得做过，好像是要遍历父子链
	function getDivPos(div)
	{
		var pos={};
		pos.x = div.offsetLeft;
		pos.y = div.offsetTop;
		while(div.offsetParent!=null)
		{
			div = div.offsetParent;
			pos.x += div.offsetLeft;
			pos.y += div.offsetTop;
		}
		return pos;
	}
	function calcOffset(event)
	{
		if (event.offsetX != null)
			return;
		
		var pos = getDivPos(event.target);
		event.offsetX = event.clientX - pos.x + document.body.scrollLeft;
		event.offsetY = event.clientY - pos.y + document.body.scrollTop;
	}	

	var onMouseDown = function ( event ) {
		drag = true;
		first = true;
	}
	var onMouseUp = function ( event ) {
		drag = false;
	}
	var onMouseMove = function ( event ) {

		/*
		var movementX = event.movementX || event.mozMovementX || event.webkitMovementX || 0;
		var movementY = event.movementY || event.mozMovementY || event.webkitMovementY || 0;
		*/
		
		if (event.originalEvent.touches !=null)
		{
			if (event.originalEvent.touches.length>=2)//缩放
			{
				var m1 = event.originalEvent.touches[0];
				var m2 = event.originalEvent.touches[1];
				var dx = m1.clientX-m2.clientX;
				var dy = m1.clientY-m2.clientY;
				
				var dist = Math.sqrt(dx*dx+dy*dy);
				var delta = dist - lastDist;
				lastDist = dist;
				if (first)
				{
					first = false;
					return;
				}				

				if (delta>0 && camera.fov>5){
					camera.fov*=0.99;
					camera.updateProjectionMatrix();
				}else if (delta<0 && camera.fov<90){
					camera.fov*=1.01;;
					camera.updateProjectionMatrix();
				} 
				
				
				return;				
			}
			else if (event.originalEvent.touches.length>=1)//模仿鼠标
			{
				event = event.originalEvent.touches[0];
				// 重点touch消息里没有offseXY数值，我得想办法从其他数值计算出来
				calcOffset(event);
				//
				event.buttons = 1;
			}
			else //说明length=0，应该不可能
			{
				return;				
			}
		}
		
		var movementX = event.offsetX-lastX;
		var movementY = event.offsetY-lastY;
		lastX = event.offsetX;
		lastY = event.offsetY;
		
		if (first)
		{
			first = false;
			return;
		}


		if ( self.enabled == false ) 
			return;
		// event.button\buttons\which和按键有关
		// 但没有按键时，button也等于0，和左键冲突
		// buttons=1、4、2，好像是ie的定义
		// which=1、2、3，比较正常
		//if (event.which == 0)//左中右健按下，意味着开始拖拽，ie下放开按键后，仍然保持状态
		//	return;
		if (event.buttons == 0)//左中右健按下，意味着开始拖拽
			return;			
		if (!drag)
			return;
		
		// 对camera施加一个微小的旋转，直接改变matrix
		
		// 1 更新prs到matrix
		//camera.updateMatrix();
		
		//		
		var angleZ = 0.02*camera.fov*movementX/div.clientHeight;
		var angleX = 0.02*camera.fov*movementY/div.clientHeight;
		
		
		var dir = camera.getWorldDirection();		
		var up = new THREE.Vector3(0,0,1);
		var side = new THREE.Vector3();
		side.crossVectors(dir, up);
		side.normalize();		
		var rotX = new THREE.Quaternion(); rotX.setFromAxisAngle(side, angleX);
		var rotZ = new THREE.Quaternion(); rotZ.setFromAxisAngle(up, angleZ);

		// 限制上下不能垂直
		var temp = new THREE.Vector3();
		temp.copy(dir);
		temp.applyQuaternion(rotX);
		if (Math.abs(temp.z)<0.9)
			dir.applyQuaternion(rotX);
		dir.applyQuaternion(rotZ);	
		
		var pos = camera.position;
		var tar = new THREE.Vector3();
		tar.addVectors(pos, dir);
		camera.up.set(0,0,1);
		camera.lookAt(tar);
		
		// 这里一大堆是为了从视线计算出航向角
		var dir = camera.getWorldDirection();
		// 注意，heading的目的地是leaflet的orientedMarker
		// 他的起始轴是y轴，但正方向是顺时针
		var heading= Math.atan2(dir.x, dir.y)*180/Math.PI;//[-pi, pi]	
		var fovy = camera.fov;
		var fovx = (Math.atan(Math.tan(fovy/2)*camera.aspect)*2)*180/Math.PI;
		var eventEye = {heading:heading, fovx:fovx};
		self.onRot(eventEye);
		
	};

	this.dispose = function() {

		$div.unbind( 'mousemove', onMouseMove );
		$div.unbind( 'mousedown', onMouseDown );
		$div.unbind( 'mouseup', onMouseUp );
		// $div.unbind( 'touchmove', onMouseMove );
		// $div.unbind( 'touchstart', onMouseDown );
		// $div.unbind( 'touchend', onMouseUp );

	};

	$div.bind( 'mousemove', onMouseMove );
	$div.bind( 'mousedown', onMouseDown );
	$div.bind( 'mouseup', onMouseUp );
	$div.bind( 'touchmove', onMouseMove );
	$div.bind( 'touchstart', onMouseDown );
	$div.bind( 'touchend', onMouseUp );
	
	
	



	
	this.enabled = false;

};