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十三、OSG学习笔记-osgDB文件读写-CSDN博客https://blog.csdn.net/weixin_36323170/article/details/146165712

本章节代码：

OsgStudy/EventHandle · CuiQingCheng/OsgStudy - 码云 - 开源中国https://gitee.com/cuiqingcheng/osg-study/tree/master/OsgStudy/EventHandle

一、事件的概念

事件：是计算机应用程序和人通过外设进行交互的途径。

核心模块 OSG::GA，通过事件回调，遍历响应各个事件处理的handle方法，所以在是现实时，可以通过自定义handle处理方法，从而实现事件操作器；

示例代码如下：

/**
	osg 事件处理器
**/

#include <windows.h>
#include <iostream>

#include <osgViewer/Viewer>
#include <osgDB/ReaderWriter>
#include <osgDB/ReadFile>
#include <osgGA/GUIEventHandler>
#include <osg/MatrixTransform>


class TestInput:public osgGA::GUIEventHandler
{
public:
	// aa ,就是viewer
	bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa) override
	{
		osgViewer::Viewer* vw = dynamic_cast<osgViewer::Viewer*>(&aa);
		switch (ea.getEventType())
		{
		case osgGA::GUIEventAdapter::KEYDOWN:
			std::cout << ea.getKey() << std::endl;
			_keyMap[ea.getKey()] = true;
			if (((_keyMap['w'] == true) || (_keyMap['W'] == true)) && ((_keyMap['a'] == true) || (_keyMap['A'] == true)))
			{
				std::cout << "应该向左前方走" << std::endl;
			}

			if (ea.getKey() == osgGA::GUIEventAdapter::KEY_Alt_L)
			{
				std::cout << "按下了左边的ALT键" << std::endl;
			}
			break;
		case osgGA::GUIEventAdapter::KEYUP:
			_keyMap[ea.getKey()] = false;
			break;
		case osgGA::GUIEventAdapter::PUSH:
			if (ea.getButton() == osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON)
			{
				std::cout << "左键点击（" << ea.getX() << "," << ea.getY() << ")" << std::endl;
			}
			else if (ea.getButton() == osgGA::GUIEventAdapter::RIGHT_MOUSE_BUTTON)
			{
				std::cout << "右键点击（" << ea.getX() << "," << ea.getY() << ")" << std::endl;
			}
			else if (ea.getButton() == osgGA::GUIEventAdapter::MIDDLE_MOUSE_BUTTON)
			{
				std::cout << "中键点击（" << ea.getX() << "," << ea.getY() << ")" << std::endl;
			}
			else {
			}
			break;

		case osgGA::GUIEventAdapter::DRAG:// 拖拽
			std::cout << "你DRAG了" << std::endl;
			break;
		case osgGA::GUIEventAdapter::SCROLL: // 滚轮事件
			if (ea.getScrollingMotion() == osgGA::GUIEventAdapter::SCROLL_UP)// 滚轮向上
			{
				osg::ref_ptr<osg::MatrixTransform> mx = new osg::MatrixTransform;
				mx->addChild(vw->getSceneData());
				mx->setMatrix(osg::Matrix::rotate(0.1, osg::Vec3f(1.0, 0, 0)));
				vw->setSceneData(mx);
			}
			else if (ea.getScrollingMotion() == osgGA::GUIEventAdapter::SCROLL_DOWN) // 滚轮向下
			{
				osg::ref_ptr<osg::MatrixTransform> mx = new osg::MatrixTransform;
				mx->addChild(vw->getSceneData());
				mx->setMatrix(osg::Matrix::rotate(-0.1, osg::Vec3f(1.0, 0, 0)));
				vw->setSceneData(mx);
			}
			break;
		case osgGA::GUIEventAdapter::RESIZE:
			std::cout << "改变窗口大小" << std::endl;
			break;
		default:
			break;
		}
		//return true;// 如果为true,这这个事件不往后传递。
		return false;
	}

private:
	std::map<int, bool>	_keyMap; // 按键状态记录map
};



int main()
{
	osg::ref_ptr<osgViewer::Viewer> viewer = new osgViewer::Viewer;

	viewer->setUpViewInWindow(50, 50, 1500, 1000);
	viewer->setSceneData(osgDB::readNodeFile("glider.osg"));
	osg::ref_ptr<TestInput> Test = new TestInput;
	viewer->addEventHandler(Test);// 加入事件
	viewer->run();
	return 0;
}