//第三人称摄像机更随   var cameraTransform : Transform;    //跟随相机 private var _target : Transform;    //跟随物体  // The distance in the x-z plane to the target  var distance = 7.0;   //相机距离物理的距离  // the height we want the camera to be above the target var height = 3.0;  //相机距离物体的高度  var angularSmoothLag = 0.3;   var angularMaxSpeed = 15.0;  var heightSmoothLag = 0.3;  var snapSmoothLag = 0.2; var snapMaxSpeed = 720.0;  var clampHeadPositionScreenSpace = 0.75;  var lockCameraTimeout = 0.2;  private var headOffset = Vector3.zero; private var centerOffset = Vector3.zero;  private var heightVelocity = 0.0; private var angleVelocity = 0.0; private var snap = false; private var controller : ThirdPersonController; private var targetHeight = 100000.0;      function Awake () { 	if(!cameraTransform && Camera.main) 		cameraTransform = Camera.main.transform;  //获取主相机 	if(!cameraTransform) { 		Debug.Log("Please assign a camera to the ThirdPersonCamera script."); 		enabled = false;	 	} 			 		 	_target = transform; 	if (_target) 	{ 		controller = _target.GetComponent(ThirdPersonController);   	} 	 	if (controller) 	{ 		var characterController : CharacterController = _target.collider; 		centerOffset = characterController.bounds.center - _target.position; 		headOffset = centerOffset; 		headOffset.y = characterController.bounds.max.y - _target.position.y; 	} 	else 		Debug.Log("Please assign a target to the camera that has a ThirdPersonController script attached.");  	 	Cut(_target, centerOffset); }  function DebugDrawStuff () { 	Debug.DrawLine(_target.position, _target.position + headOffset);  }  function AngleDistance (a : float, b : float) { 	a = Mathf.Repeat(a, 360); 	b = Mathf.Repeat(b, 360); 	 	return Mathf.Abs(b - a); }  function Apply (dummyTarget : Transform, dummyCenter : Vector3) { 	// Early out if we don't have a target 	if (!controller) 		return; 	 	var targetCenter = _target.position + centerOffset; 	var targetHead = _target.position + headOffset;  //	DebugDrawStuff();  	// Calculate the current & target rotation angles 	var originalTargetAngle = _target.eulerAngles.y; 	var currentAngle = cameraTransform.eulerAngles.y;  	// Adjust real target angle when camera is locked 	var targetAngle = originalTargetAngle;  	 	// When pressing Fire2 (alt) the camera will snap to the target direction real quick. 	// It will stop snapping when it reaches the target 	if (Input.GetButton("Fire2")) 		snap = true; 	 	if (snap) 	{ 		// We are close to the target, so we can stop snapping now! 		if (AngleDistance (currentAngle, originalTargetAngle) < 3.0) 			snap = false; 		 		currentAngle = Mathf.SmoothDampAngle(currentAngle, targetAngle, angleVelocity, snapSmoothLag, snapMaxSpeed); 	} 	// Normal camera motion 	else 	{ 		if (controller.GetLockCameraTimer () < lockCameraTimeout) 		{ 			targetAngle = currentAngle; 		}  		// Lock the camera when moving backwards! 		// * It is really confusing to do 180 degree spins when turning around. 		if (AngleDistance (currentAngle, targetAngle) > 160 && controller.IsMovingBackwards ()) 			targetAngle += 180;  		currentAngle = Mathf.SmoothDampAngle(currentAngle, targetAngle, angleVelocity, angularSmoothLag, angularMaxSpeed); 	}   	// When jumping don't move camera upwards but only down! 	if (controller.IsJumping ()) 	{ 		// We'd be moving the camera upwards, do that only if it's really high 		var newTargetHeight = targetCenter.y + height; 		if (newTargetHeight < targetHeight || newTargetHeight - targetHeight > 5) 			targetHeight = targetCenter.y + height; 	} 	// When walking always update the target height 	else 	{ 		targetHeight = targetCenter.y + height; 	}  	// Damp the height 	var currentHeight = cameraTransform.position.y; 	currentHeight = Mathf.SmoothDamp (currentHeight, targetHeight, heightVelocity, heightSmoothLag);  	// Convert the angle into a rotation, by which we then reposition the camera 	var currentRotation = Quaternion.Euler (0, currentAngle, 0); 	 	// Set the position of the camera on the x-z plane to: 	// distance meters behind the target 	cameraTransform.position = targetCenter; 	cameraTransform.position += currentRotation * Vector3.back * distance;  	// Set the height of the camera 	cameraTransform.position.y = currentHeight; 	 	// Always look at the target	 	SetUpRotation(targetCenter, targetHead); }  function LateUpdate () { 	Apply (transform, Vector3.zero); }    function Cut (dummyTarget : Transform, dummyCenter : Vector3) { 	var oldHeightSmooth = heightSmoothLag; 	var oldSnapMaxSpeed = snapMaxSpeed; 	var oldSnapSmooth = snapSmoothLag; 	 	snapMaxSpeed = 10000; 	snapSmoothLag = 0.001; 	heightSmoothLag = 0.001; 	 	snap = true; 	Apply (transform, Vector3.zero); 	 	heightSmoothLag = oldHeightSmooth; 	snapMaxSpeed = oldSnapMaxSpeed; 	snapSmoothLag = oldSnapSmooth; }  function SetUpRotation (centerPos : Vector3, headPos : Vector3) { 	// Now it's getting hairy. The devil is in the details here, the big issue is jumping of course. 	// * When jumping up and down we don't want to center the guy in screen space. 	//  This is important to give a feel for how high you jump and avoiding large camera movements. 	//    	// * At the same time we dont want him to ever go out of screen and we want all rotations to be totally smooth. 	// 	// So here is what we will do: 	// 	// 1. We first find the rotation around the y axis. Thus he is always centered on the y-axis 	// 2. When grounded we make him be centered 	// 3. When jumping we keep the camera rotation but rotate the camera to get him back into view if his head is above some threshold 	// 4. When landing we smoothly interpolate towards centering him on screen 	var cameraPos = cameraTransform.position; 	var offsetToCenter = centerPos - cameraPos; 	 	// Generate base rotation only around y-axis 	var yRotation = Quaternion.LookRotation(Vector3(offsetToCenter.x, 0, offsetToCenter.z));  	var relativeOffset = Vector3.forward * distance + Vector3.down * height; 	cameraTransform.rotation = yRotation * Quaternion.LookRotation(relativeOffset);  	// Calculate the projected center position and top position in world space 	var centerRay = cameraTransform.camera.ViewportPointToRay(Vector3(.5, 0.5, 1)); 	var topRay = cameraTransform.camera.ViewportPointToRay(Vector3(.5, clampHeadPositionScreenSpace, 1));  	var centerRayPos = centerRay.GetPoint(distance); 	var topRayPos = topRay.GetPoint(distance); 	 	var centerToTopAngle = Vector3.Angle(centerRay.direction, topRay.direction); 	 	var heightToAngle = centerToTopAngle / (centerRayPos.y - topRayPos.y);  	var extraLookAngle = heightToAngle * (centerRayPos.y - centerPos.y); 	if (extraLookAngle < centerToTopAngle) 	{ 		extraLookAngle = 0; 	} 	else 	{ 		extraLookAngle = extraLookAngle - centerToTopAngle; 		cameraTransform.rotation *= Quaternion.Euler(-extraLookAngle, 0, 0); 	} }  function GetCenterOffset () { 	return centerOffset; }