OSG学习:使用已有回调示例
回调的类型有很多种,一般很容易就想到的是UpdateCallBack,或者EventCallBack,回调的意思就是说,你可以规定在某件事情发生时启动一个函数,这个函数可能做一些事情。这个函数就叫做回调函数。
#include<osg\MatrixTransform> #include<osg\PositionAttitudeTransform> #include<osg\Geode> #include<osgDB\Registry> #include<osgDB\ReadFile> #include<osgGA\TrackballManipulator> #include<osgViewer\Viewer> //创建一条路径 osg::AnimationPath* createAnimationPath(const osg::Vec3& center, float radius, double looptime) { //路径实体 osg::AnimationPath* animationPath = new osg::AnimationPath; //设置循环模式为LOOP animationPath->setLoopMode(osg::AnimationPath::LOOP); //设置关键点数 int numSamples = 40; float yaw = 0.0f; float yaw_delta = 2.0f*osg::PI / ((float)numSamples - 1.0f); float roll = osg::inDegrees(30.0f); //设置时间间隔 double time = 0.0f; double time_delta = looptime / (double)numSamples; //插入关键点与时间以及旋转角度和位置 for (int i = 0; i < numSamples; ++i) { osg::Vec3 position(0, 0, 0); osg::Quat rotation(osg::Quat(roll, osg::Vec3(0.0, 1.0, 0.0))*osg::Quat(-(yaw + osg::inDegrees(90.0f)), osg::Vec3(0.0, 0.0, 1.0))); //具体插入操作 animationPath->insert(time, osg::AnimationPath::ControlPoint(position, rotation)); yaw += yaw_delta; time += time_delta; } return animationPath; } //创建移动模型 osg::Node* createMovingModel(const osg::Vec3& center, float radius) { float animationLength = 10.0f; //创建的路径 osg::AnimationPath* animationPath = createAnimationPath(center, radius, animationLength); osg::Group* model = new osg::Group; //读取模型,并隐藏它下面的第一个节点 osg::Node* fountain = osgDB::readNodeFile("fountain.osgt"); fountain->asGroup()->getChild(0)->setNodeMask(0); //如果读取成功,则更新赋予它的路径 if (fountain) { osg::PositionAttitudeTransform* xform = new osg::PositionAttitudeTransform; //设置更新回调 xform->setUpdateCallback(new osg::AnimationPathCallback(animationPath, 0.0, 1.0)); //加入子模型节点 xform->addChild(fountain); model->addChild(xform); } return model; } //创建模型 osg::Node* createModel() { osg::Vec3 center(0.0f, 0.0f, 0.0f); float radius = 1.0f; osg::Group* root = new osg::Group; //创建移动的节点,以radius为半径转圈 osg::Node* movingModel = createMovingModel(center, radius*0.8f); //把节点加入到root中并返回 root->addChild(movingModel); return root; } //主函数 int main(int argc, char** argv) { osgViewer::Viewer viewer; //创建模型 osg::Node* model = createModel(); viewer.setSceneData(model); viewer.setCameraManipulator(new osgGA::TrackballManipulator()); viewer.realize(); return viewer.run(); }结果图: