OSG中的节点

1.多个模型添加到一个场景中去

#include <osgViewer/Viewer>

#include <osgDB/ReadFile>

#include <osg/Node>
int main(void)
{
osgViewer::Viewer viewer;
osg::Group * root = new osg::Group();
root->addChild(osgDB::readNodeFile("sofa.osg"));
root->addChild(osgDB::readNodeFile("cow.osg"));
viewer.setSceneData(root);
viewer.realize();
viewer.run();
return 0;

}

出现下面效果：

删除节点：

#include <osgViewer/Viewer>
#include <osgDB/ReadFile>
#include <osg/Node>
int main(void)
{
osgViewer::Viewer viewer;
osg::Group * root = new osg::Group();
root->addChild(osgDB::readNodeFile("sofa.osg"));
osg::Node * cow = osgDB::readNodeFile("cow.osg");
root->removeChild(cow);
viewer.setSceneData(root);
viewer.realize();
viewer.run();
return 0;
}

添加节点：

#include <osgViewer/Viewer>
#include <osgDB/ReadFile>
#include <osg/Node>
int main(void)
{
osgViewer::Viewer viewer;
osg::Group * root = new osg::Group();
root->addChild(osgDB::readNodeFile("sofa.osg"));
osg::Node * cow = osgDB::readNodeFile("cow.osg");
root->addChild(cow);
viewer.setSceneData(root);
viewer.realize();
viewer.run();
return 0;
}

隐藏节点：

仅仅隐藏物体，其真实还是占内存的

node->setNodeMask()可以设置隐藏与显示，node->setNodeMask(0x0)表示隐藏，node->setNodeMask(1)表示显示。

#include <osgViewer/Viewer>
#include <osgDB/ReadFile>
#include <osg/Node>
int main(void)
{
osgViewer::Viewer viewer;
osg::Group * root = new osg::Group();
osg::Node * osg = osgDB::readNodeFile("sofa.osg");
root->addChild(osg);
root->addChild(osgDB::readNodeFile("cow.osg"));
osg->setNodeMask(0x0);
viewer.setSceneData(root);
viewer.realize();
viewer.run();
return 0;

}

结果如下：sofa被隐藏，只有cow显示

模型矩形的变换

模型的移动、旋转、缩放其实都是对矩阵进行操作，矩阵可以当作一个特殊的结点加入到组结点中。

通过osg::MatrixTransform定义变换矩阵，
通过setMatrix(osg::Matrix::translate(x, y, z))实现模型移动，
通过setMatrix(osg::Matrix::scale(x, y, z))实现模型缩放，

通过setMatrix(osg::Matrix::rotate(x, y, z))实现模型旋转。

osg的坐标轴，默认向上是Z，向右是X，向内是Y

#include <osgViewer/Viewer>
#include <osgDB/ReadFile>
# include <osg/Node>
# include <osg/MatrixTransform>
int main(void)
{
osgViewer::Viewer viewer;
osg::ref_ptr<osg::Group> root = new osg::Group;
osg::ref_ptr<osg::Node> sofa = osgDB::readNodeFile("sofa.osg");

osg::ref_ptr<osg::MatrixTransform> trans = new osg::MatrixTransform;
trans->setMatrix(osg::Matrix::translate(0, 0, 2));
trans->addChild(sofa.get());

osg::ref_ptr<osg::MatrixTransform> scale = new osg::MatrixTransform;
scale->setMatrix(osg::Matrix::scale(0.5, 0.5, 0.5) * osg::Matrix::translate(0, 0, -2));
scale->addChild(sofa.get());

osg::ref_ptr<osg::MatrixTransform> rot = new osg::MatrixTransform;
rot->setMatrix(osg::Matrix::rotate(osg::DegreesToRadians(45.0), 1, 0, 0) * osg::Matrix::scale(0.5, 0.5, 0.5) * osg::Matrix::translate(4, 0, -2));
rot->addChild(sofa.get());

root->addChild(sofa.get());
root->addChild(trans.get());
root->addChild(scale.get());
root->addChild(rot);

viewer.setSceneData(root.get());
viewer.realize();
viewer.run();
return 0;

}

根据自己给的角度或长度进行平移，旋转，缩放

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