Merge /u/amalon/flightgear/ branch vr_1 into next

https://sourceforge.net/p/flightgear/flightgear/merge-requests/253/

CMakeLists.txt

@@ -151,6 +151,11 @@ elseif(${CMAKE_SYSTEM_NAME} MATCHES "Linux" OR
     if(HTS_ENGINE_FOUND)
         set(SYSTEM_HTS_ENGINE_DEFAULT 1)
     endif()
+
+    find_package(osgXR 0.3)
+    if (osgXR_FOUND)
+        set(ENABLE_OSGXR_DEFAULT 1)
+    endif()
 endif()
 
 # FlightGear build options
@@ -171,6 +176,7 @@ option(SYSTEM_GSM        "Set to ON to build IAXClient with the system's GSM lib
 option(SYSTEM_FLITE      "Set to ON to build Flightgear with the system's Flite library" ${SYSTEM_FLITE_DEFAULT})
 option(SYSTEM_HTS_ENGINE "Set to ON to build Flightgear with the system's HTS Engine library" ${SYSTEM_HTS_ENGINE_DEFAULT})
 option(SYSTEM_CPPUNIT    "Set to ON to build Flightgear with the system's CppUnit library")
+option(ENABLE_OSGXR      "Set to ON to build Flightgear with OpenXR support via the osgXR library" ${ENABLE_OSGXR_DEFAULT})
 
 # additional utilities
 option(ENABLE_FGELEV     "Set to ON to build the fgelev application (default)" ON)

CMakeModules/SetupFGFSIncludes.cmake

@@ -4,6 +4,10 @@ function(setup_fgfs_includes target)
         target_include_directories(${target} PRIVATE ${PROJECT_SOURCE_DIR}/src/FDM/JSBSim)
     endif()
 
+    if(ENABLE_OSGXR)
+        target_include_directories(${target} PRIVATE ${osgXR_INCLUDE_DIR})
+    endif()
+
     target_include_directories(${target} PRIVATE ${PLIB_INCLUDE_DIR})
     target_include_directories(${target} PRIVATE ${PROJECT_SOURCE_DIR}/3rdparty/cjson)
     # only actually needed for httpd.cxx

CMakeModules/SetupFGFSLibraries.cmake

@@ -23,6 +23,10 @@ function(setup_fgfs_libraries target)
         target_link_libraries(${target} ${X11_LIBRARIES})
     endif()
 
+    if(ENABLE_OSGXR)
+        target_link_libraries(${target} osgXR::osgXR)
+    endif()
+
     target_link_libraries(${target} fgsqlite3 fgvoicesynth fgembeddedresources)
 
     target_link_libraries(${target}

scripts/completion/fg-completion.zsh

@@ -60,6 +60,8 @@ _fgfs_options=(
 	'--enable-skyblend[Enable sky blending]' \
 	'--disable-textures[Disable textures]' \
 	'--enable-textures[Enable textures]' \
+        '--disable-vr[Disable VR]' \
+        '--enable-vr[Enable VR]' \
 	'--disable-wireframe[Disable wireframe drawing mode]' \
 	'--enable-wireframe[Enable wireframe drawing mode]' \
 	'--notrim[Do NOT attempt to trim the model (only with fdm=jsbsim)]' \

src/Include/config_cmake.h.in

@@ -27,6 +27,7 @@
 #define FLIGHTGEAR_VERSION "@FLIGHTGEAR_VERSION@"
 #define FLIGHTGEAR_MAJOR_VERSION @FG_VERSION_MAJOR@
 #define FLIGHTGEAR_MINOR_VERSION @FG_VERSION_MINOR@
+#define FLIGHTGEAR_PATCH_VERSION @FG_VERSION_PATCH@
 
 #cmakedefine ENABLE_UIUC_MODEL
 #cmakedefine ENABLE_LARCSIM
@@ -75,3 +76,5 @@
 
 #cmakedefine HAVE_SENTRY
 #define SENTRY_API_KEY "@sentry_api_key@"
+
+#cmakedefine ENABLE_OSGXR

src/Main/options.cxx

@@ -1900,6 +1900,10 @@ struct OptionDesc {
     {"disable-wireframe",            false, OPTION_BOOL,   "/sim/rendering/wireframe", false, "", 0 },
     {"enable-wireframe",             false, OPTION_BOOL,   "/sim/rendering/wireframe", true, "", 0 },
     {"materials-file",               true,  OPTION_STRING, "/sim/rendering/materials-file", false, "", 0 },
+#ifdef ENABLE_OSGXR
+    {"disable-vr",                   false, OPTION_BOOL,   "/sim/vr/enabled", false, "", 0 },
+    {"enable-vr",                    false, OPTION_BOOL,   "/sim/vr/enabled", true, "", 0 },
+#endif
     {"disable-terrasync",            false, OPTION_BOOL,   "/sim/terrasync/enabled", false, "", 0 },
     {"enable-terrasync",             false, OPTION_BOOL,   "/sim/terrasync/enabled", true, "", 0 },
     {"terrasync-dir",                true,  OPTION_IGNORE, "", false, "", 0 },

src/Viewer/CMakeLists.txt

@@ -28,8 +28,15 @@ set(HEADERS
 	viewmgr.hxx
 	sview.hxx
 	GraphicsPresets.hxx
+	VRManager.hxx
 	)
 
+if (ENABLE_OSGXR)
+	list(APPEND SOURCES
+		VRManager.cxx
+		)
+endif()
+
 if (YES)
     list(APPEND HEADERS PUICamera.hxx)
     list(APPEND SOURCES PUICamera.cxx)

src/Viewer/CameraGroup.cxx

@@ -477,7 +477,7 @@ void CameraGroup::buildDistortionCamera(const SGPropertyNode* psNode,
 #endif
 }
 
-void CameraGroup::buildCamera(SGPropertyNode* cameraNode)
+CameraInfo* CameraGroup::buildCamera(SGPropertyNode* cameraNode)
 {
     WindowBuilder *wBuild = WindowBuilder::getWindowBuilder();
     const SGPropertyNode* windowNode = cameraNode->getNode("window");
@@ -491,7 +491,7 @@ void CameraGroup::buildCamera(SGPropertyNode* cameraNode)
         window = wBuild->buildWindow(cameraNode);
     }
     if (!window) {
-        return;
+        return nullptr;
     }
 
     osg::Matrix vOff;
@@ -599,7 +599,7 @@ void CameraGroup::buildCamera(SGPropertyNode* cameraNode)
         if (it == _cameras.end()) {
             SG_LOG(SG_VIEW, SG_ALERT, "CameraGroup::buildCamera: "
                    "failed to find parent camera for relative camera!");
-            return;
+            return nullptr;
         }
         parentInfo = (*it);
         if (projectionNode->getNameString() == "right-of-perspective") {
@@ -717,6 +717,18 @@ void CameraGroup::buildCamera(SGPropertyNode* cameraNode)
         info->flags = info->flags | CameraInfo::VIEW_ABSOLUTE;
         //buildDistortionCamera(psNode, camera);
     }
+
+    return info;
+}
+
+void CameraGroup::removeCamera(CameraInfo *info)
+{
+    for (auto it = _cameras.begin(); it != _cameras.end(); ++it) {
+        if (*it == info) {
+            _cameras.erase(it);
+            return;
+        }
+    }
 }
 
 void CameraGroup::buildGUICamera(SGPropertyNode* cameraNode,
@@ -970,6 +982,9 @@ void reloadCompositors(CameraGroup *cgroup)
             SGReaderWriterOptions::fromPath(globals->get_fg_root());
         options->setPropertyNode(globals->get_props());
 
+        if (info->reloadCompositorCallback.valid())
+            info->reloadCompositorCallback->preReloadCompositor(cgroup, info);
+
         // Force deletion
         info->compositor.reset(nullptr);
         // Then replace it with a new instance
@@ -981,6 +996,9 @@ void reloadCompositors(CameraGroup *cgroup)
                                                   viewport,
                                                   compositor_path,
                                                   options));
+
+        if (info->reloadCompositorCallback.valid())
+            info->reloadCompositorCallback->postReloadCompositor(cgroup, info);
     }
 
     cgroup->_viewer->getViewerBase()->startThreading();

src/Viewer/CameraGroup.hxx

@@ -51,6 +51,7 @@ namespace flightgear
 
 class CameraGroupListener;
 class GraphicsWindow;
+class CameraGroup;
 
 /** A wrapper around osg::Camera that contains some extra information.
  */
@@ -76,7 +77,7 @@ struct CameraInfo : public osg::Referenced
         flags(flags_),
         physicalWidth(0), physicalHeight(0), bezelHeightTop(0),
         bezelHeightBottom(0), bezelWidthLeft(0), bezelWidthRight(0),
-        relativeCameraParent(0) { }
+        relativeCameraParent(0), reloadCompositorCallback(nullptr) { }
     /** The name as given in the config file.
      */
     std::string name;
@@ -120,6 +121,14 @@ struct CameraInfo : public osg::Referenced
      * Compositor path and should use the default one.
      */
     std::string compositor_path;
+
+    struct ReloadCompositorCallback : public virtual osg::Referenced
+    {
+        virtual void preReloadCompositor(CameraGroup *, CameraInfo *) = 0;
+        virtual void postReloadCompositor(CameraGroup *, CameraInfo *) = 0;
+    };
+    osg::ref_ptr<ReloadCompositorCallback> reloadCompositorCallback;
+
 };
 
 class CameraGroup : public osg::Referenced
@@ -150,7 +159,11 @@ public:
      * @param cameraNode the property node.
      * @return a CameraInfo object for the camera.
      */
-    void buildCamera(SGPropertyNode* cameraNode);
+    CameraInfo* buildCamera(SGPropertyNode* cameraNode);
+    /** Remove a camera from the camera group.
+     * @param info the camera info to remove.
+     */
+    void removeCamera(CameraInfo *info);
     /** Create a camera from properties that will draw the GUI and add
      * it to the camera group.
      * @param cameraNode the property node. This can be 0, in which

src/Viewer/VRManager.cxx

@@ -0,0 +1,221 @@
+// Copyright (C) 2021  James Hogan
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+#include "VRManager.hxx"
+#include "WindowBuilder.hxx"
+#include "renderer.hxx"
+
+#include <osgXR/Settings>
+
+#include <simgear/scene/viewer/CompositorPass.hxx>
+
+#include <Main/fg_props.hxx>
+#include <Main/globals.hxx>
+
+namespace flightgear
+{
+
+VRManager::VRManager() :
+    _reloadCompositorCallback(new ReloadCompositorCallback(this)),
+    _propXrLayersValidation("/sim/vr/openxr/layers/validation"),
+    _propXrExtensionsDepthInfo("/sim/vr/openxr/extensions/depth-info"),
+    _propXrRuntimeName("/sim/vr/openxr/runtime/name"),
+    _propXrSystemName("/sim/vr/openxr/system/name"),
+    _propStateString("/sim/vr/state-string"),
+    _propPresent("/sim/vr/present"),
+    _propRunning("/sim/vr/running"),
+    _propEnabled("/sim/vr/enabled"),
+    _propDepthInfo("/sim/vr/depth-info"),
+    _propValidationLayer("/sim/vr/validation-layer"),
+    _propMode("/sim/vr/mode"),
+    _propSwapchainMode("/sim/vr/swapchain-mode"),
+    _listenerEnabled(this, &osgXR::Manager::setEnabled),
+    _listenerDepthInfo(this, &VRManager::setDepthInfo),
+    _listenerValidationLayer(this, &VRManager::setValidationLayer),
+    _listenerMode(this, &VRManager::setVRMode),
+    _listenerSwapchainMode(this, &VRManager::setSwapchainMode)
+{
+    uint32_t fgVersion = (FLIGHTGEAR_MAJOR_VERSION << 16 |
+                          FLIGHTGEAR_MINOR_VERSION << 8 |
+                          FLIGHTGEAR_PATCH_VERSION);
+    _settings->setApp("FlightGear", fgVersion);
+    _settings->preferEnvBlendMode(osgXR::Settings::OPAQUE);
+
+    // Hook into viewer, but don't enable VR just yet
+    osgViewer::View *view = globals->get_renderer()->getView();
+    if (view) {
+        setViewer(globals->get_renderer()->getViewerBase());
+        view->apply(this);
+    }
+
+    syncReadOnlyProperties();
+
+    _propEnabled.node(true)->addChangeListener(&_listenerEnabled, true);
+    _propDepthInfo.node(true)->addChangeListener(&_listenerDepthInfo, true);
+    _propValidationLayer.node(true)->addChangeListener(&_listenerValidationLayer, true);
+    _propMode.node(true)->addChangeListener(&_listenerMode, true);
+    _propSwapchainMode.node(true)->addChangeListener(&_listenerSwapchainMode, true);
+}
+
+VRManager *VRManager::instance()
+{
+    static osg::ref_ptr<VRManager> single = new VRManager;
+    return single;
+}
+
+void VRManager::syncProperties()
+{
+    // If the state has changed, properties may need synchronising
+    if (checkAndResetStateChanged()) {
+        syncReadOnlyProperties();
+        syncSettingProperties();
+    }
+}
+
+void VRManager::syncReadOnlyProperties()
+{
+    _propXrLayersValidation = hasValidationLayer();
+    _propXrExtensionsDepthInfo = hasDepthInfoExtension();
+    _propXrRuntimeName = getRuntimeName();
+    _propXrSystemName = getSystemName();
+
+    _propStateString = getStateString();
+    _propPresent = getPresent();
+    _propRunning = isRunning();
+}
+
+void VRManager::syncSettingProperties()
+{
+    bool enabled = getEnabled();
+    if (_propEnabled != enabled)
+        _propEnabled = enabled;
+}
+
+void VRManager::setValidationLayer(bool validationLayer)
+{
+    _settings->setValidationLayer(validationLayer);
+    syncSettings();
+}
+
+void VRManager::setDepthInfo(bool depthInfo)
+{
+    _settings->setDepthInfo(depthInfo);
+    syncSettings();
+}
+
+void VRManager::setVRMode(const char * mode)
+{
+    osgXR::Settings::VRMode vrMode = osgXR::Settings::VRMODE_AUTOMATIC;
+
+    if (strcmp(mode, "AUTOMATIC") == 0) {
+        vrMode = osgXR::Settings::VRMODE_AUTOMATIC;
+    } else if (strcmp(mode, "SLAVE_CAMERAS") == 0) {
+        vrMode = osgXR::Settings::VRMODE_SLAVE_CAMERAS;
+    } else if (strcmp(mode, "SCENE_VIEW") == 0) {
+        vrMode = osgXR::Settings::VRMODE_SCENE_VIEW;
+    }
+
+    _settings->setVRMode(vrMode);
+    syncSettings();
+}
+
+void VRManager::setSwapchainMode(const char * mode)
+{
+    osgXR::Settings::SwapchainMode swapchainMode = osgXR::Settings::SWAPCHAIN_AUTOMATIC;
+
+    if (strcmp(mode, "AUTOMATIC") == 0) {
+        swapchainMode = osgXR::Settings::SWAPCHAIN_AUTOMATIC;
+    } else if (strcmp(mode,"MULTIPLE") == 0) {
+        swapchainMode = osgXR::Settings::SWAPCHAIN_MULTIPLE;
+    } else if (strcmp(mode,"SINGLE") == 0) {
+        swapchainMode = osgXR::Settings::SWAPCHAIN_SINGLE;
+    }
+
+    _settings->setSwapchainMode(swapchainMode);
+    syncSettings();
+}
+
+void VRManager::update()
+{
+    osgXR::Manager::update();
+    syncProperties();
+}
+
+void VRManager::doCreateView(osgXR::View *xrView)
+{
+    // Restarted in osgXR::Manager::update()
+    _viewer->stopThreading();
+
+    // Construct a property tree for the camera
+    SGPropertyNode_ptr camNode = new SGPropertyNode;
+    WindowBuilder *windowBuilder = WindowBuilder::getWindowBuilder();
+    setValue(camNode->getNode("window/name", true),
+             windowBuilder->getDefaultWindowName());
+
+    // Build a camera
+    CameraGroup *cgroup = CameraGroup::getDefault();
+    CameraInfo *info = cgroup->buildCamera(camNode);
+
+    // Notify osgXR about the new compositor's scene slave cameras
+    if (info) {
+        _camInfos[xrView] = info;
+        _xrViews[info] = xrView;
+        info->reloadCompositorCallback = _reloadCompositorCallback;
+
+        postReloadCompositor(cgroup, info);
+    }
+}
+
+void VRManager::doDestroyView(osgXR::View *xrView)
+{
+    // Restarted in osgXR::Manager::update()
+    _viewer->stopThreading();
+
+    CameraGroup *cgroup = CameraGroup::getDefault();
+    auto it = _camInfos.find(xrView);
+    if (it != _camInfos.end()) {
+        osg::ref_ptr<CameraInfo> info = (*it).second;
+        _camInfos.erase(it);
+
+        auto it2 = _xrViews.find(info.get());
+        if (it2 != _xrViews.end())
+            _xrViews.erase(it2);
+
+        cgroup->removeCamera(info.get());
+    }
+}
+
+void VRManager::preReloadCompositor(CameraGroup *cgroup, CameraInfo *info)
+{
+    osgXR::View *xrView = _xrViews[info];
+
+    auto& passes = info->compositor->getPassList();
+    for (auto& pass: passes)
+        if (pass->type == "scene")
+            xrView->removeSlave(pass->camera);
+}
+
+void VRManager::postReloadCompositor(CameraGroup *cgroup, CameraInfo *info)
+{
+    osgXR::View *xrView = _xrViews[info];
+
+    auto& passes = info->compositor->getPassList();
+    for (auto& pass: passes)
+        if (pass->type == "scene")
+            xrView->addSlave(pass->camera);
+}
+
+}

src/Viewer/VRManager.hxx

@@ -0,0 +1,158 @@
+// Copyright (C) 2021  James Hogan
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License as
+// published by the Free Software Foundation; either version 2 of the
+// License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+#ifndef VRMANAGER_HXX
+#define VRMANAGER_HXX 1
+
+#include <config.h>
+
+#ifdef ENABLE_OSGXR
+
+#include <osg/ref_ptr>
+#include <osg/observer_ptr>
+
+#include <osgXR/Manager>
+
+#include <simgear/props/propertyObject.hxx>
+#include <simgear/scene/viewer/CompositorPass.hxx>
+
+#include "CameraGroup.hxx"
+
+#include <map>
+
+namespace flightgear
+{
+
+class VRManager : public osgXR::Manager
+{
+    public:
+
+        class ReloadCompositorCallback : public CameraInfo::ReloadCompositorCallback
+        {
+            public:
+
+                ReloadCompositorCallback(VRManager *manager) :
+                    _manager(manager)
+                {
+                };
+
+                virtual void preReloadCompositor(CameraGroup *cgroup, CameraInfo *info)
+                {
+                    _manager->preReloadCompositor(cgroup, info);
+                }
+
+                virtual void postReloadCompositor(CameraGroup *cgroup, CameraInfo *info)
+                {
+                    _manager->postReloadCompositor(cgroup, info);
+                }
+
+            protected:
+
+                osg::observer_ptr<VRManager> _manager;
+        };
+
+        VRManager();
+
+        static VRManager *instance();
+
+        void syncProperties();
+        void syncReadOnlyProperties();
+        void syncSettingProperties();
+
+        // Settings
+
+        void setValidationLayer(bool validationLayer);
+        void setDepthInfo(bool depthInfo);
+
+        void setVRMode(const char * mode);
+        void setSwapchainMode(const char * mode);
+
+        // osgXR::Manager overrides
+
+        void update() override;
+
+        void doCreateView(osgXR::View *xrView) override;
+        void doDestroyView(osgXR::View *xrView) override;
+
+        void preReloadCompositor(CameraGroup *cgroup, CameraInfo *info);
+        void postReloadCompositor(CameraGroup *cgroup, CameraInfo *info);
+
+    protected:
+
+        typedef std::map<osgXR::View *, osg::ref_ptr<CameraInfo>> XRViewToCamInfo;
+        XRViewToCamInfo _camInfos;
+
+        typedef std::map<CameraInfo *, osg::ref_ptr<osgXR::View>> CamInfoToXRView;
+        CamInfoToXRView _xrViews;
+
+        osg::ref_ptr<ReloadCompositorCallback> _reloadCompositorCallback;
+
+        // Properties
+
+        SGPropObjBool _propXrLayersValidation;
+        SGPropObjBool _propXrExtensionsDepthInfo;
+        SGPropObjString _propXrRuntimeName;
+        SGPropObjString _propXrSystemName;
+
+        SGPropObjString _propStateString;
+        SGPropObjBool _propPresent;
+        SGPropObjBool _propRunning;
+
+        SGPropObjBool _propEnabled;
+        SGPropObjBool _propDepthInfo;
+        SGPropObjBool _propValidationLayer;
+        SGPropObjString _propMode;
+        SGPropObjString _propSwapchainMode;
+
+        // Property listeners
+
+        template <typename T>
+        class Listener : public SGPropertyChangeListener
+        {
+            public:
+                typedef void (VRManager::*SetterFn)(T v);
+
+                Listener(VRManager *manager, SetterFn setter) :
+                    _manager(manager),
+                    _setter(setter)
+                {
+                }
+
+                void valueChanged(SGPropertyNode *node) override
+                {
+                    (_manager->*_setter)(node->template getValue<T>());
+                }
+
+            protected:
+
+                VRManager *_manager;
+                SetterFn _setter;
+        };
+        typedef Listener<bool> ListenerBool;
+        typedef Listener<const char *> ListenerString;
+
+        ListenerBool _listenerEnabled;
+        ListenerBool _listenerDepthInfo;
+        ListenerBool _listenerValidationLayer;
+        ListenerString _listenerMode;
+        ListenerString _listenerSwapchainMode;
+};
+
+}
+
+#endif // ENABLE_OSGXR
+
+#endif

src/Viewer/fg_os_osgviewer.cxx

@@ -52,6 +52,7 @@
 #include "renderer.hxx"
 #include "CameraGroup.hxx"
 #include "FGEventHandler.hxx"
+#include "VRManager.hxx"
 #include "WindowBuilder.hxx"
 #include "WindowSystemAdapter.hxx"
 #include <Main/sentryIntegration.hxx>
@@ -328,6 +329,12 @@ void fgOSResetProperties()
     fgTie("/sim/rendering/osg-displaysettings/double-buffer", displaySettings, &DisplaySettings::getDoubleBuffer, &DisplaySettings::setDoubleBuffer );
     fgTie("/sim/rendering/osg-displaysettings/depth-buffer", displaySettings, &DisplaySettings::getDepthBuffer, &DisplaySettings::setDepthBuffer );
     fgTie("/sim/rendering/osg-displaysettings/rgb", displaySettings, &DisplaySettings::getRGB, &DisplaySettings::setRGB );
+
+#ifdef ENABLE_OSGXR
+    fgSetBool("/sim/vr/built", true);
+#else
+    fgSetBool("/sim/vr/built", false);
+#endif
 }
 
 
@@ -389,6 +396,9 @@ int fgOSMainLoop()
             }
         }
         globals->get_renderer()->update();
+#ifdef ENABLE_OSGXR
+        VRManager::instance()->update();
+#endif
         viewer_base->frame( globals->get_sim_time_sec() );
     }
 
@@ -437,6 +447,9 @@ void fgOSCloseWindow()
             viewer_base->stopThreading();
         }
     }
+#ifdef ENABLE_OSGXR
+    VRManager::instance()->destroyAndWait();
+#endif
     FGScenery::resetPagerSingleton();
     flightgear::addSentryBreadcrumb("fgOSCloseWindow, clearing camera group", "info");
     flightgear::CameraGroup::setDefault(NULL);