Simplify canvas OpenVG initialization and fix sometimes rendering too lazy

src/Canvas/canvas.cxx

@@ -22,7 +22,6 @@
 #include <Canvas/MouseEvent.hxx>
 #include <Canvas/property_helper.hxx>
 #include <Main/fg_props.hxx>
-#include <Main/globals.hxx>
 #include <Viewer/CameraGroup.hxx>
 #include <Viewer/renderer.hxx>
 
@@ -49,16 +48,7 @@ class Canvas::DrawCallback:
 
     virtual void operator()(osg::RenderInfo& renderInfo) const
     {
-      const long frame = renderInfo.getView()->getFrameStamp()
+      _canvas->_render_dirty = false;
-                                             ->getFrameNumber();
-
-      static SGPropertyNode_ptr node_frame =
-        globals->get_props()->getNode(canvas::VG_INIT_SIGNAL, true);
-
-      // If OpenVG has been initialized we need to redraw the frame, because
-      // initializing has happened instead of rendering.
-      // Otherwise we just reset the _render_dirty flag.
-      _canvas->_render_dirty = (frame == node_frame->getLongValue());
     }
 
   protected:

src/Canvas/canvas_fwd.hpp

@@ -32,8 +32,6 @@ typedef boost::weak_ptr<Canvas> CanvasWeakPtr;
 
 namespace canvas
 {
-  const std::string VG_INIT_SIGNAL = "/sim/signals/vg-initialized-frame";
-
   class Group;
   class Image;
   class MouseEvent;

src/Canvas/elements/path.cxx

@@ -52,24 +52,10 @@ namespace canvas
         setDataVariance(Object::DYNAMIC);
 
         setUpdateCallback(new PathUpdateCallback());
-        setCullCallback(new NoCullCallback());
       }
 
       virtual ~PathDrawable()
       {
-        if( !_vg_initialized )
-        {
-          if( _path != VG_INVALID_HANDLE )
-            SG_LOG
-            (
-              SG_GL,
-              SG_WARN,
-              "Can't destroy path without OpenVG context: "
-                << _path_element->_node->getPath()
-            );
-          return;
-        }
-
         if( _path != VG_INVALID_HANDLE )
           vgDestroyPath(_path);
         if( _paint != VG_INVALID_HANDLE )
@@ -93,7 +79,7 @@ namespace canvas
         _cmds = cmds;
         _coords = coords;
 
-        _attributes_dirty |= PATH;
+        _attributes_dirty |= (PATH | BOUNDING_BOX);
       }
 
       /**
@@ -182,7 +168,7 @@ namespace canvas
        */
       virtual void drawImplementation(osg::RenderInfo& renderInfo) const
       {
-        if( (_attributes_dirty & PATH) && _vg_initialized )
+        if( _attributes_dirty & PATH )
           return;
 
         osg::State* state = renderInfo.getState();
@@ -196,21 +182,6 @@ namespace canvas
                            // eg. doesn't include GL_MULTISAMPLE_BIT
         glPushClientAttrib(~0u);
 
-        // Initialize OpenVG itself
-        if( !_vg_initialized )
-        {
-          GLint vp[4];
-          glGetIntegerv(GL_VIEWPORT, vp);
-
-          vgCreateContextSH(vp[2], vp[3]);
-          _vg_initialized = true;
-
-          fgSetInt( canvas::VG_INIT_SIGNAL,
-                    renderInfo.getView()->getFrameStamp()->getFrameNumber() );
-
-          return;
-        }
-
         // Initialize/Update the paint
         if( _attributes_dirty & STROKE_COLOR )
         {
@@ -268,7 +239,7 @@ namespace canvas
        */
       virtual osg::BoundingBox computeBound() const
       {
-        if( _path == VG_INVALID_HANDLE )
+        if( _path == VG_INVALID_HANDLE || (_attributes_dirty & PATH) )
           return osg::BoundingBox();
 
         VGfloat min[2], size[2];
@@ -291,8 +262,6 @@ namespace canvas
 
     private:
 
-      static bool _vg_initialized;
-
       enum Attributes
       {
         PATH            = 0x0001,
@@ -352,45 +321,16 @@ namespace canvas
           dirtyBound();
       }
 
-      /**
-       * Updating the path before drawing is needed to enable correct bounding
-       * box calculations and make culling work.
-       */
       struct PathUpdateCallback:
         public osg::Drawable::UpdateCallback
       {
         virtual void update(osg::NodeVisitor*, osg::Drawable* drawable)
         {
-          if( !_vg_initialized )
-            return;
           static_cast<PathDrawable*>(drawable)->update();
         }
       };
-
-      /**
-       * Callback used to prevent culling as long as OpenVG is not initialized.
-       * This is needed because OpenVG needs an active OpenGL context for
-       * initialization which is only available in #drawImplementation.
-       * As soon as OpenVG is correctly initialized the callback automatically
-       * removes itself from the node, so that the normal culling can get
-       * active.
-       */
-      struct NoCullCallback:
-        public osg::Drawable::CullCallback
-      {
-        virtual bool cull( osg::NodeVisitor*,
-                           osg::Drawable* drawable,
-                           osg::State* ) const
-        {
-          if( _vg_initialized )
-            drawable->setCullCallback(0);
-          return false;
-        }
-      };
   };
 
-  bool Path::PathDrawable::_vg_initialized = false;
-
   //----------------------------------------------------------------------------
   Path::Path(SGPropertyNode_ptr node, const Style& parent_style):
     Element(node, parent_style),

src/Main/main.cxx

@@ -34,6 +34,7 @@
 #include <osgDB/Registry>
 
 // Class references
+#include <simgear/canvas/VGInitOperation.hxx>
 #include <simgear/scene/model/modellib.hxx>
 #include <simgear/scene/material/matlib.hxx>
 #include <simgear/props/AtomicChangeListener.hxx>
@@ -52,6 +53,7 @@
 #include <GUI/gui.h>
 #include <Viewer/splash.hxx>
 #include <Viewer/renderer.hxx>
+#include <Viewer/WindowSystemAdapter.hxx>
 #include <Navaids/NavDataCache.hxx>
 
 #include "fg_commands.hxx"
@@ -249,6 +251,9 @@ static void fgIdleFunction ( void ) {
 
         globals->get_renderer()->resize( fgGetInt("/sim/startup/xsize"),
                                          fgGetInt("/sim/startup/ysize") );
+        WindowSystemAdapter::getWSA()->windows[0]->gc->add(
+          new simgear::canvas::VGInitOperation()
+        );
 
         int session = fgGetInt("/sim/session",0);
         session++;