基于Qt的OSG三维建模

以下是一个基于Qt和OpenSceneGraph（OSG）实现三维模型交互的示例代码，包含模型高亮、文本标注等功能。代码采用Qt5和OSG 3.6版本开发。

一、核心类设计（C++）

1. 主窗口类（继承QMainWindow）

#include <osgQt/GraphicsWindowQt>
#include <osgViewer/Viewer>class OsgWidget : public QWidget {
public:OsgWidget(QWidget* parent = nullptr) : QWidget(parent), viewer(new osgViewer::Viewer) {osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits;traits->x = x(); traits->y = y();traits->width = width(); traits->height = height();traits->windowDecoration = false;traits->doubleBuffer = true;traits->sharedContext = 0;osgQt::GraphicsWindowQt* gw = new osgQt::GraphicsWindowQt(traits.get());viewer->getCamera()->setGraphicsContext(gw);viewer->getCamera()->setViewport(new osg::Viewport(0, 0, width(), height()));viewer->setThreadingModel(osgViewer::Viewer::SingleThreaded);viewer->addEventHandler(new PickHandler());  // 自定义事件处理器}osgViewer::Viewer* getViewer() { return viewer.get(); }protected:virtual void paintEvent(QPaintEvent*) {viewer->frame();update();}private:osg::ref_ptr<osgViewer::Viewer> viewer;
};

matlab代码实现

二、点击高亮实现

1. 自定义事件处理器

class PickHandler : public osgGA::GUIEventHandler {
public:bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa) override {if (ea.getEventType() == osgGA::GUIEventAdapter::RELEASE && ea.getButton() == osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON) {osgViewer::View* view = dynamic_cast<osgViewer::View*>(&aa);if(view) pick(view, ea.getX(), ea.getY());return true;}return false;}void pick(osgViewer::View* view, float x, float y) {osgUtil::LineSegmentIntersector::Intersections intersections;if (view->computeIntersections(x, y, intersections)) {auto it = intersections.begin();osg::Node* node = it->nodePath.back();// 高亮处理toggleHighlight(node);// 文本标注addTextLabel(it->getWorldIntersectPoint(), "Selected Object");}}void toggleHighlight(osg::Node* node) {static osg::ref_ptr<osg::StateSet> prevState;// 清除之前的高亮if (prevState) prevState->setAttributeAndModes(new osg::PolygonMode, osg::StateAttribute::OVERRIDE | osg::StateAttribute::OFF);// 设置新选中物体的高亮材质osg::StateSet* ss = node->getOrCreateStateSet();ss->setAttribute(new osg::PolygonMode(osg::PolygonMode::FRONT_AND_BACK, osg::PolygonMode::LINE));ss->setAttributeAndModes(new osg::LineWidth(3.0f));ss->setMode(GL_LIGHTING, osg::StateAttribute::OFF);prevState = ss;}
};

三、动态文本标注实现

1. 文字标注管理器

class TextLabelManager {
public:void addTextLabel(const osg::Vec3& position, const std::string& content) {osg::ref_ptr<osgText::Text> text = new osgText::Text;text->setFont("fonts/arial.ttf");text->setCharacterSize(0.5f);text->setPosition(position);text->setText(content);text->setAxisAlignment(osgText::Text::SCREEN);text->setColor(osg::Vec4(1,1,0,1));osg::ref_ptr<osg::Geode> geode = new osg::Geode;geode->addDrawable(text.get());_root->addChild(geode);_labels.push_back(geode);}void setRootNode(osg::Group* root) { _root = root; }private:osg::ref_ptr<osg::Group> _root;std::vector<osg::ref_ptr<osg::Geode>> _labels;
};

四、场景初始化

1. 创建基础场景

osg::Node* createScene() {osg::ref_ptr<osg::Group> root = new osg::Group;// 示例模型：立方体osg::ref_ptr<osg::Box> box = new osg::Box(osg::Vec3(0,0,0), 1.0f);osg::ref_ptr<osg::Geode> geode = new osg::Geode;geode->addDrawable(new osg::ShapeDrawable(box));root->addChild(geode);// 初始化文本管理器TextLabelManager::instance()->setRootNode(root);return root.release();
}

五、功能扩展建议

1. 高级标注功能

// 带箭头的标注线
void addAnnotationLine(const osg::Vec3& start, const osg::Vec3& end) {osg::ref_ptr<osg::Geometry> lineGeom = new osg::Geometry;osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;vertices->push_back(start);vertices->push_back(end);lineGeom->setVertexArray(vertices);lineGeom->addPrimitiveSet(new osg::DrawArrays(GL_LINES,0,2));osg::ref_ptr<osg::Geode> geode = new osg::Geode;geode->addDrawable(lineGeom);_root->addChild(geode);
}// 可编辑文本标注
class EditableText : public osgText::Text {
public:void setEditable(bool editable) {// 实现文本编辑交互逻辑}
};

六、运行效果增强技巧

视觉优化：

// 文字背景板
text->setBackdropType(osgText::Text::OUTLINE);
text->setBackdropColor(osg::Vec4(0,0,0,1));

// 高亮发光效果 ss->setAttribute(new osg::BlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)); ss->setAttribute(new osg::LineStipple(1, 0x0F0F));

2. **性能优化**：
```cpp
// 使用LOD管理标注可见性
osg::LOD* lod = new osg::LOD;
lod->addChild(textGeode, 0.0, 50.0);  // 50米内可见// 批处理绘制调用
osg::ref_ptr<osg::Geometry> batchGeometry = new osg::Geometry;
// ...（合并多个标注几何体）

七、工程配置关键点（CMake）

find_package(Qt5 COMPONENTS Core Widgets REQUIRED)
find_package(OpenSceneGraph REQUIRED)add_executable(osg_demo main.cpp OsgWidget.cppPickHandler.cpp)target_link_libraries(osg_demo Qt5::Widgets OpenThreads::OpenThreads osg::osg osg::osgViewer osg::osgText)