OSG LineSegmentIntersector进行碰撞检测

#include <osgViewer/Viewer> #include <osgViewer/ViewerEventHandlers> #include <osgGA/StateSetManipulator> #include <osgDB/ReadFile> #include <osgUtil/LineSegmentIntersector> #include <osgUtil/IntersectionVisitor> #include <osg/MatrixTransform> #include <osg/Group> #include <osg/Node> int main() { osg::ref_ptr<osg::Node> cow = osgDB::readNodeFile("cow.osg");//第一个节点 osg::ref_ptr<osg::Node> axes = osgDB::readNodeFile("axes.osg");//第二个节点 osg::ref_ptr<osg::MatrixTransform> mt_cow = new osg::MatrixTransform; mt_cow->setMatrix(osg::Matrix::scale(osg::Vec3(0.5,0.5,0.5))*osg::Matrix::translate(osg::Vec3(-10,0,0))); mt_cow->addChild(cow.get()); osg::ref_ptr<osg::MatrixTransform> mt_axes = new osg::MatrixTransform; mt_axes->addChild(axes.get()); osg::ref_ptr<osg::Group> root = new osg::Group; root->addChild(mt_cow.get()); root->addChild(mt_axes.get()); osgViewer::Viewer * viewer = new osgViewer::Viewer; viewer->addEventHandler(new osgGA::StateSetManipulator(viewer->getCamera()->getOrCreateStateSet())); /************************************************************************/ /* 碰撞检测 */ /************************************************************************/ osg::Vec3 p_start(-100,0,0); osg::Vec3 p_end(100,0,0); osgUtil::LineSegmentIntersector::Intersections _intersections; osg::ref_ptr< osgUtil::LineSegmentIntersector > _lineSegmentIntersector = new osgUtil::LineSegmentIntersector(p_start,p_end); osgUtil::IntersectionVisitor _iv(_lineSegmentIntersector.get()); cow->accept(_iv); _intersections=_lineSegmentIntersector->getIntersections(); int _intersectionNumber=_intersections.size(); if (_intersectionNumber!=0) { osgUtil::LineSegmentIntersector::Intersections::iterator hitr = _intersections.begin(); osg::Vec3 vec3_p1 =hitr->getWorldIntersectPoint()*mt_cow->getMatrix();//这样得到的交点就是绝对的世界坐标了。 mt_axes->setMatrix(osg::Matrix::translate(vec3_p1));//把坐标系原点移动到交点，可以测试现在的坐标系原点是不是刚好和牛相交！ hitr++; osg::Vec3 vec3_p2 =hitr->getWorldIntersectPoint()*mt_cow->getMatrix(); } viewer->setSceneData(root.get()); return viewer->run(); }

在参考了多个例子后写了这么一个例子，总算明白了进行线段相交的各个步骤的含义了。