应用程序插件框架的内容包括：主程序App，插件Plugin。
1、实现一个应用程序插架框架关键点有：
一个插件的标准接口，在主程序中存在一个插件的集合。主程序通过循环读取每个插件，将插件对象通过多态的机制转换为插件接口，实现插件的装载。
主程序对象或者主程序接口需要作为参数传递到插件对象中，以方便插件对象调用主程序的内容，如主视图、工具栏、树视图、状态栏等。
2、开源点云处理软件CloudCompare也是一个插件框架，因此也必然包括这些内容。
插件接口：ccPluginInterface，每个插件对象有在ccPluginInterface基础上定义了一个新的接口类class ccStdPluginInterface : public ccPluginInterface
具体的插件则继承自ccStdPluginInterface 累，比如这样，class qMyPlugin : public QObject, public ccStdPluginInterface
主程序对象：class ccMainAppInterface，MainWindow主窗体类实现了ccMainAppInterface接口。
MainWindow::loadPlugins()方法负责插件的调用。（mainwindow.cpp文件中）
1 void MainWindow::loadPlugins() 2 { 3 menuPlugins->setEnabled(false); 4 menuShadersAndFilters->setEnabled(false); 5 toolBarPluginTools->setVisible(false); 6 toolBarGLFilters->setVisible(false); 7 8 //"static" plugins 9 foreach (QObject *plugin, QPluginLoader::staticInstances())10 dispatchPlugin(plugin);11 12 ccConsole::Print(QString("Application path: ")+QCoreApplication::applicationDirPath());13 14 #if defined(Q_OS_MAC)15 // plugins are in the bundle16 QString path = QCoreApplication::applicationDirPath();17 path.remove( "MacOS" );18 m_pluginsPath = path + "Plugins/ccPlugins";19 #else20 //plugins are in bin/plugins21 m_pluginsPath = QCoreApplication::applicationDirPath()+QString("/plugins");22 #endif23 24 ccConsole::Print(QString("Plugins lookup dir.: %1").arg(m_pluginsPath));25 26 QStringList filters;27 #if defined(Q_OS_WIN)28 filters << "*.dll";29 #elif defined(Q_OS_LINUX)30 filters << "*.so";31 #elif defined(Q_OS_MAC)32 filters << "*.dylib";33 #endif34 QDir pluginsDir(m_pluginsPath);35 pluginsDir.setNameFilters(filters);36 foreach (QString filename, pluginsDir.entryList(filters))37 {38 QPluginLoader loader(pluginsDir.absoluteFilePath(filename));39 QObject* plugin = loader.instance();40 if (plugin)41 {42 ccConsole::Print(QString("Found new plugin: '%1'").arg(filename));43 if (dispatchPlugin(plugin))44 {45 m_pluginFileNames += filename;46 }47 else48 {49 delete plugin;50 plugin = 0;51 ccConsole::Warning("\tUnsupported or invalid plugin type");52 }53 }54 else55 {56 delete plugin;57 plugin = 0;58 ccConsole::Warning(QString("[Plugin] %1")/*.arg(pluginsDir.absoluteFilePath(filename))*/.arg(loader.errorString()));59 }60 }61 62 if (menuPlugins)63 {64 menuPlugins->setEnabled(!m_stdPlugins.empty());65 }66 67 if (toolBarPluginTools->isEnabled())68 {69 actionDisplayPluginTools->setEnabled(true);70 actionDisplayPluginTools->setChecked(true);71 }72 else73 {74 //DGM: doesn't work :(75 //actionDisplayPluginTools->setChecked(false);76 }77 78 if (toolBarGLFilters->isEnabled())79 {80 actionDisplayGLFiltersTools->setEnabled(true);81 actionDisplayGLFiltersTools->setChecked(true);82 }83 else84 {85 //DGM: doesn't work :(86 //actionDisplayGLFiltersTools->setChecked(false);87 }88 } 主程序在加载插件时会调用插件的setMainAppInterface方法，将主程序参数传入，这样插件就可以获取主程序的内容了。
1 //! Sets application entry point2 /** Called just after plugin creation by qCC3 **/4 virtual void setMainAppInterface(ccMainAppInterface* app);
3、获取主窗体中的点云图层
在doAction中的代码：
1 const ccHObject::Container& selectedEntities = m_app->getSelectedEntities(); 2 size_t selNum = selectedEntities.size(); 3 if (selNum!=1) 4 { 5 m_app->dispToConsole("Select only one cloud!",ccMainAppInterface::ERR_CONSOLE_MESSAGE); 6 return; 7 } 8 9 ccHObject* ent = selectedEntities[0];10 assert(ent);11 if (!ent || !ent->isA(CC_TYPES::POINT_CLOUD))12 {13 m_app->dispToConsole("Select a real point cloud!",ccMainAppInterface::ERR_CONSOLE_MESSAGE);14 return;15 }16 17 ccPointCloud* pc = static_cast (ent);18 19 //input cloud20 unsigned count = pc->size();21 bool hasNorms = pc->hasNormals();22 CCVector3 bbMin, bbMax;23 pc->getBoundingBox(bbMin,bbMax);24 const CCVector3d& globalShift = pc->getGlobalShift();25 double globalScale = pc->getGlobalScale();