Fix view right-drag interaction with PUI

When PUI doesn’t handle the right-mouse down, ensure it ignores the
mouse-up event.

src/Input/FGMouseInput.cxx

@@ -714,5 +714,14 @@ void FGMouseInput::doMouseMotion (int x, int y, const osgGA::GUIEventAdapter* ea
   d->mouseYNode->setIntValue(y);
 }
 
+bool FGMouseInput::isRightDragToLookEnabled() const
+{
+    if (!d->initialized) {
+        return false;
+    }
+
+    return (d->rightClickModeCycle == false);
+}
+
 
 

src/Input/FGMouseInput.hxx

@@ -43,11 +43,20 @@ public:
   FGMouseInput();
   virtual ~FGMouseInput();
 
-  virtual void init();
-  virtual void update( double dt );
+    void init() override;
+    void update( double dt ) override;
+
+    static const char* subsystemName() { return "input-mouse"; }
 
     void doMouseClick (int b, int updown, int x, int y, bool mainWindow, const osgGA::GUIEventAdapter* ea);
     void doMouseMotion (int x, int y, const osgGA::GUIEventAdapter*);
+
+    /**
+     * @brief isRightDragToLookEnabled - test if we're in right-mouse-drag
+     * to adjust the view direction/position mode.
+     * @return
+     */
+    bool isRightDragToLookEnabled() const;
 private:
   void processMotion(int x, int y, const osgGA::GUIEventAdapter* ea);
     

src/Input/input.cxx

@@ -62,7 +62,7 @@ FGInput::FGInput ()
   if( fgGetBool("/sim/input/no-mouse-input",false) ) {
     SG_LOG(SG_INPUT,SG_ALERT,"Mouse input disabled!");
   } else {
-    set_subsystem( "input-mouse", new FGMouseInput() );
+    set_subsystem( FGMouseInput::subsystemName(), new FGMouseInput() );
   }
 
   if( fgGetBool("/sim/input/no-keyboard-input",false) ) {

src/Input/input.hxx

@@ -26,15 +26,9 @@
 #ifndef _INPUT_HXX
 #define _INPUT_HXX
 
-#ifndef __cplusplus                                                          
-# error This library requires C++
-#endif
 
 #include <simgear/structure/subsystem_mgr.hxx>
 
-
-
-
 
 ////////////////////////////////////////////////////////////////////////
 // General input mapping support.
@@ -61,6 +55,8 @@ public:
    */
   virtual ~FGInput();
 
+  static const char* subsystemName() { return "input"; }
+
 };
 
 #endif // _INPUT_HXX

src/Main/fg_init.cxx

@@ -919,7 +919,7 @@ void fgCreateSubsystems(bool duringReset) {
     // Initialize the input subsystem.
     ////////////////////////////////////////////////////////////////////
 
-    globals->add_subsystem("input", new FGInput, SGSubsystemMgr::GENERAL);
+    globals->add_new_subsystem<FGInput>(SGSubsystemMgr::GENERAL);
 
 
     ////////////////////////////////////////////////////////////////////

src/Viewer/PUICamera.cxx

@@ -43,6 +43,9 @@
 #include <Viewer/CameraGroup.hxx>
 #include <Viewer/FGEventHandler.hxx>
 
+#include <Input/input.hxx>
+#include <Input/FGMouseInput.hxx>
+
 // Old versions of PUI are missing these defines
 #ifndef PU_SCROLL_UP_BUTTON
 #define PU_SCROLL_UP_BUTTON 3
@@ -99,7 +102,9 @@ class PUIEventHandler : public osgGA::GUIEventHandler
 public:
     PUIEventHandler(PUICamera* cam) :
         _puiCamera(cam)
-    {}
+    {
+        _mouse0RightButtonNode = fgGetNode("/devices/status/mice/mouse[0]/button[2]", true);
+    }
     
     bool handle(const osgGA::GUIEventAdapter &ea, osgGA::GUIActionAdapter &aa, osg::Object *, osg::NodeVisitor *nv) override
     {
@@ -117,22 +122,29 @@ public:
             case(osgGA::GUIEventAdapter::MOVE):
             case(osgGA::GUIEventAdapter::DRAG):
             {
+                FGMouseInput* mouseSubsystem = globals->get_subsystem<FGInput>()->get_subsystem<FGMouseInput>();
+                if (mouseSubsystem &&
+                    mouseSubsystem->isRightDragToLookEnabled() &&
+                    _mouse0RightButtonNode->getBoolValue())
+                {
+                    return false;
+                }
+
                 bool handled = puMouse(scaledX, scaledY);
                 return handled;
             }
-                // you might thnk the code below is a good idea, but apparently it's not
-                // PUI synthesises PU_DRAG internally, it doesn't want to see it delivered
-                // from the windowing system
-#if 0
-            case(osgGA::GUIEventAdapter::DRAG):
-            {
-                bool handled = puMouse(osgButtonToPUI(ea), PU_DRAG, scaledX, scaledY);
-                return handled;
-            }
-#endif
+
             case(osgGA::GUIEventAdapter::PUSH):
             case(osgGA::GUIEventAdapter::RELEASE):
             {
+                FGMouseInput* mouseSubsystem = globals->get_subsystem<FGInput>()->get_subsystem<FGMouseInput>();
+                if (mouseSubsystem &&
+                    mouseSubsystem->isRightDragToLookEnabled() &&
+                    _mouse0RightButtonNode->getBoolValue())
+                {
+                    return false;
+                }
+
                 bool upOrDown = (ea.getEventType() == osgGA::GUIEventAdapter::RELEASE);
                 bool handled = puMouse(osgButtonToPUI(ea), upOrDown, scaledX, scaledY);
                 return handled;
@@ -215,6 +227,7 @@ private:
     }
     
     PUICamera* _puiCamera;
+    SGPropertyNode_ptr _mouse0RightButtonNode;
 };
 
 // The pu getWindow callback is supposed to return a window ID that