OSG学习：响应键盘鼠标示例

示例功能：示例里面有两个模型，一个是牛，另一个是飞机。鼠标右键时牛和飞机都隐藏，鼠标左键双击时牛和飞机都显示，按键盘上面的LEFT键，显示牛，按键盘上面的RIGHT键显示飞机。其中显示与隐藏节点使用的是setNodeMask(bool)。bool的值为0的时候是隐藏，1的时候是显示。

#include<osgDB\ReadFile>
#include<osgViewer\Viewer>
#include<osg\Node>

class UseEventHandler :public osgGA::GUIEventHandler
{
public:
	virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
	{
		osgViewer::Viewer* viewer = dynamic_cast<osgViewer::Viewer*>(&aa);
		if (!viewer)return false;

		switch (ea.getEventType())
		{
		case osgGA::GUIEventAdapter::KEYDOWN:
		{
												if (ea.getKey() == 0xFF51)
												{
													viewer->getSceneData()->asGroup()->getChild(1)->setNodeMask(0);
													viewer->getSceneData()->asGroup()->getChild(0)->setNodeMask(1);
												}
												if (ea.getKey() == 0xFF53)
												{
													viewer->getSceneData()->asGroup()->getChild(0)->setNodeMask(0);
													viewer->getSceneData()->asGroup()->getChild(1)->setNodeMask(1);
												}
												break;
		}
		case osgGA::GUIEventAdapter::PUSH:
			if (ea.getButton() == 4)
			{
				viewer->getSceneData()->asGroup()->getChild(0)->setNodeMask(0);
				viewer->getSceneData()->asGroup()->getChild(1)->setNodeMask(0);
			}
			break;
		case osgGA::GUIEventAdapter::DOUBLECLICK:
			if (ea.getButton() == 1)
			{
				viewer->getSceneData()->asGroup()->getChild(0)->setNodeMask(1);
				viewer->getSceneData()->asGroup()->getChild(1)->setNodeMask(1);
			}
			break;
		default:
			break;
		}
		return false;
	}
};

void main()
{
	osgViewer::Viewer viewer;
	osg::ref_ptr<osg::Group> root = new osg::Group();
	root->addChild(osgDB::readNodeFile("cow.osg"));
	root->addChild(osgDB::readNodeFile("glider.osg"));
	viewer.setSceneData(root.get());
	viewer.addEventHandler(new UseEventHandler);
	viewer.realize();
	viewer.run();
}

结果图：