/*
1.创建一个AnimManager一般继承于osg::NodeCallback
2.在AnimManager中创建一个采样器sampler（例如Vec3LinearSampler，有各种sammpler）
3. sammpler 配置了各种Interpolator（插值器，如Vec3LinearInterpolator）
4.sampler 中有KeyframeContainer(关键帧容器，如Vec3KeyframeContainer）
5.向keyframeContainer中插入对应的关键帧（如Vec3Keyframe 关键帧中包含时间戳和对应的数据类型(如Vec3)）；
6.取值 sampler->getValueAt(time t,p1) t 为时间，p1为对应的数据类型如Vec3，当时间超出sampler的结束时间，或取值永远是最后一帧。
7.取出的p1 用到你想用的地方。
*/

#include <iostream>
#include <osg/io_utils>
#include <osg/Geometry>
#include <osg/Shape>
#include <osg/ShapeDrawable>
#include <osg/Material>
#include <osg/MatrixTransform>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
#include <osgGA/TrackballManipulator>
#include <osgAnimation/Sampler>


class MyNode
{
public:
	MyNode(std::string f,float x,float y,float z) 
	{
		id = f;
		_v = osg::Vec3(x,y,z);
	}
	MyNode(){ id = "";}
	MyNode( const MyNode&no)
	{
		id = no.id;
		_v = no._v;
 
	}
	MyNode & operator = (const MyNode&no)
	{
		id = no.id;
		_v = no._v;
	 
		return *this;
	}
	const  MyNode    operator * (float  v) const //不能返回引用，因为no是临时对象
	{
		MyNode no;
		no.id = id;
		no._v = _v*v;
		return  no;
	}
	inline float operator * (const MyNode  rhs) const
	{
		 return  _v*rhs._v;
	}

	inline MyNode operator + (const MyNode & rhs) const//不能返回引用，因为no是临时对象
	{
		 MyNode no;
		 no.id = id;
		 no._v = _v+rhs._v;
		return no;
	}
	std::string id;
	osg::Vec3 _v;
};
typedef osgAnimation::TemplateKeyframe<MyNode> MyNodeKeyframe;
typedef osgAnimation::TemplateKeyframeContainer<MyNode> MyNodeKeyframeContainer;
typedef osgAnimation::TemplateLinearInterpolator<MyNode, MyNode> MyNodeLinearInterpolator;
typedef osgAnimation::TemplateSampler<MyNodeLinearInterpolator> MyNodeLinearSampler;


class AnimManager : public osg::NodeCallback
{
public:

	AnimManager() 
	{
		_sampler = new MyNodeLinearSampler;
		_playing = false;
		_lastUpdate = 0;

	 
	}
	virtual void operator()(osg::Node* node, osg::NodeVisitor* nv)
	{ 
		if (nv->getVisitorType() == osg::NodeVisitor::UPDATE_VISITOR && 
			nv->getFrameStamp() && 
			nv->getFrameStamp()->getFrameNumber() != _lastUpdate) 
		{

			_lastUpdate = nv->getFrameStamp()->getFrameNumber();

			_currentTime = osg::Timer::instance()->tick();

			if (_playing && _sampler.get() && _sampler->getKeyframeContainer()) 
			{
				osg::MatrixTransform* transform = dynamic_cast<osg::MatrixTransform*>(node);
				if (transform) {
					osg::Vec3 result;
					float t = osg::Timer::instance()->delta_s(_startTime, _currentTime);
					//float duration = _sampler->getEndTime() - _sampler->getStartTime();
					//t = fmod(t, duration);//循环

					if(t> _sampler->getEndTime())
					{
						stop();
					}

					MyNode no;

					_sampler->getValueAt(t, no );
					result = no._v;

					std::cout<<no.id<<"  "<<result.x()<<" "<<result.y()<<"  "<<result.z()<<std::endl;
					transform->setMatrix(osg::Matrix::translate(result));
				}
			}
		}

		traverse(node,nv);
	}

	void start() { _startTime = osg::Timer::instance()->tick(); _currentTime = _startTime; _playing = true;}
	void stop() { _currentTime = _startTime; _playing = false;}

	osg::ref_ptr<MyNodeLinearSampler> _sampler;
	osg::Timer_t _startTime;
	osg::Timer_t _currentTime;
	bool _playing;
	unsigned int _lastUpdate;
};
osg::MatrixTransform* setupAnimtkNode(osg::Geode* staticGeode) 
{
	osg::MatrixTransform* node = new osg::MatrixTransform();

	AnimManager* callback = new AnimManager();
	MyNodeKeyframeContainer* keys = callback->_sampler->getOrCreateKeyframeContainer();

	keys->push_back( MyNodeKeyframe(0.0,MyNode("A",1,0,0)));
	keys->push_back( MyNodeKeyframe(1.0,MyNode("B",5,0,9)));
	keys->push_back( MyNodeKeyframe(2.0,MyNode("C",1,8,0)));
	keys->push_back( MyNodeKeyframe(3.0,MyNode("D",1,8,-5)));

	callback->start();
	node->setUpdateCallback(callback);

	osg::Geode* geode = new osg::Geode();
	geode->addDrawable(new osg::ShapeDrawable(new osg::Sphere(osg::Vec3(0.0f, 0.0f, 0.0f), 2)));

	node->addChild(geode);

	return node;
}

int main(int argc, char** argv) 
{
	osg::ArgumentParser arguments(&argc, argv);
	osgViewer::Viewer viewer(arguments);

	osgGA::TrackballManipulator* tbm = new osgGA::TrackballManipulator();

	viewer.setCameraManipulator(tbm);

	viewer.addEventHandler(new osgViewer::StatsHandler());
	viewer.addEventHandler(new osgViewer::WindowSizeHandler());

	osg::Group* root = new osg::Group();
	osg::Geode* geode = new osg::Geode();

	root->setInitialBound(osg::BoundingSphere(osg::Vec3(10,0,20), 50));
	root->addChild(setupAnimtkNode(geode));
	root->addChild(geode);

	viewer.setSceneData(root);
	return viewer.run();
}