Fix for impostors bug where image insert were visible, this was down to a double

call to RenderStage::drawPreRenderStage().  The call to it in RenderStage inside
the draw() method has been removed, leaving on the call in SceneView.

include/osg/ImpostorSprite

@@ -143,6 +143,8 @@ class SG_EXPORT ImpostorSprite : public Drawable
         /** accept a PrimtiveFunctor and call its methods to tell it about the interal primtives that this Drawable has.*/
         virtual void accept(PrimitiveFunctor& pf) const;
 
+        // for debugging purposes.
+        Vec4 _color;
 
     protected:
 

src/osg/ImpostorSprite.cpp

@@ -41,6 +41,8 @@ ImpostorSprite::ImpostorSprite()
     _texture = NULL;
     _s = 0;
     _t = 0;        
+
+    _color.set(1.0f, 1.0f, 1.0f, 1.0f );
 }
 
 ImpostorSprite::~ImpostorSprite()
@@ -77,7 +79,8 @@ void ImpostorSprite::drawImplementation(State&) const
 {
     // when the tex env is set to REPLACE, and the 
     // texture is set up correctly the color has no effect.
-    glColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
+    glColor4fv( _color.ptr() );
+    
     
     glBegin( GL_QUADS );
     
@@ -268,6 +271,7 @@ ImpostorSprite* ImpostorSpriteManager::createOrReuseImpostorSprite(int s,int t,i
     stateset->setMode(GL_LIGHTING,osg::StateAttribute::OFF);
     stateset->setMode(GL_BLEND,osg::StateAttribute::ON);
 
+    stateset->setRenderingHint( StateSet::TRANSPARENT_BIN );
 
     stateset->setAttributeAndModes( _alphafunc.get(), StateAttribute::ON );
 

src/osgUtil/CullVisitor.cpp

@@ -629,11 +629,17 @@ void CullVisitor::apply(Impostor& node)
             // create the impostor sprite.
             impostorSprite = createImpostorSprite(node);
 
+            //if (impostorSprite) impostorSprite->_color.set(0.0f,0.0f,1.0f,1.0f);
+
         }
+        //else impostorSprite->_color.set(1.0f,1.0f,1.0f,1.0f);
         
         if (impostorSprite)
         {
             
+            // update frame number to show that impostor is in action.
+            impostorSprite->setLastFrameUsed(getTraversalNumber());
+
             if (_computeNearFar) updateCalculatedNearFar(matrix,*impostorSprite);
 
             StateSet* stateset = impostorSprite->getStateSet();
@@ -644,8 +650,6 @@ void CullVisitor::apply(Impostor& node)
 
             if (stateset) popStateSet();
             
-            // update frame number to show that impostor is in action.
-            impostorSprite->setLastFrameUsed(getTraversalNumber());
             
         }
         else
@@ -886,12 +890,18 @@ ImpostorSprite* CullVisitor::createImpostorSprite(Impostor& node)
     
     dummyState->setAttribute(new_viewport);
 
-// create the impostor sprite.
-
+    // create the impostor sprite.
     ImpostorSprite* impostorSprite = 
         _impostorSpriteManager->createOrReuseImpostorSprite(new_s,new_t,getTraversalNumber()-_numFramesToKeepImpostorSprites);
 
-    if (impostorSprite==NULL) return NULL;
+    if (impostorSprite==NULL)
+    {
+        osg::notify(osg::WARN)<<"Warning: unable to create required impostor sprite."<<std::endl;
+        return NULL;
+    }
+
+    // update frame number to show that impostor is in action.
+    impostorSprite->setLastFrameUsed(getTraversalNumber());
 
     // have successfully created an impostor sprite so now need to
     // add it into the impostor.

src/osgUtil/RenderStage.cpp

@@ -79,23 +79,33 @@ void RenderStage::addToDependencyList(RenderStage* rs)
 
 void RenderStage::drawPreRenderStages(osg::State& state,RenderLeaf*& previous)
 {
+    if (_dependencyList.empty()) return;
+    
+    //cout << "Drawing prerendering stages "<<this<< "  "<<_viewport->x()<<","<< _viewport->y()<<","<< _viewport->width()<<","<< _viewport->height()<<std::endl;
     for(DependencyList::iterator itr=_dependencyList.begin();
         itr!=_dependencyList.end();
         ++itr)
     {
         (*itr)->draw(state,previous);
     }
+    //cout << "Done Drawing prerendering stages "<<this<< "  "<<_viewport->x()<<","<< _viewport->y()<<","<< _viewport->width()<<","<< _viewport->height()<<std::endl;
 }
 
 void RenderStage::draw(osg::State& state,RenderLeaf*& previous)
 {
-    drawPreRenderStages(state,previous);
+    if (_stageDrawnThisFrame) return;
+
+    _stageDrawnThisFrame = true;
+
+    // note, SceneView does call to drawPreRenderStages explicitly
+    // so there is no need to call it here.
+    //drawPreRenderStages(state,previous);
+
     RenderBin::draw(state,previous);
 }
 
 void RenderStage::drawImplementation(osg::State& state,RenderLeaf*& previous)
 {
-    if (_stageDrawnThisFrame) return;
     
     if (!_viewport)
     {
@@ -103,7 +113,6 @@ void RenderStage::drawImplementation(osg::State& state,RenderLeaf*& previous)
         return;
     }
     
-    _stageDrawnThisFrame = true;
     
     // set up the back buffer.
     state.applyAttribute(_viewport.get());
@@ -111,6 +120,8 @@ void RenderStage::drawImplementation(osg::State& state,RenderLeaf*& previous)
 #define USE_SISSOR_TEST
 #ifdef USE_SISSOR_TEST
     glScissor( _viewport->x(), _viewport->y(), _viewport->width(), _viewport->height() );
+    //cout << "    clearing "<<this<< "  "<<_viewport->x()<<","<< _viewport->y()<<","<< _viewport->width()<<","<< _viewport->height()<<std::endl;
+    
     glEnable( GL_SCISSOR_TEST );
 #endif
 
@@ -125,7 +136,10 @@ void RenderStage::drawImplementation(osg::State& state,RenderLeaf*& previous)
         glClearColor( _clearColor[0], _clearColor[1], _clearColor[2], _clearColor[3]);
 
     if (_clearMask & GL_DEPTH_BUFFER_BIT)
+    {
         glClearDepth( _clearDepth);
+    }
+    else
 
     if (_clearMask & GL_STENCIL_BUFFER_BIT)
         glClearStencil( _clearStencil);

src/osgUtil/RenderToTextureStage.cpp

@@ -35,12 +35,20 @@ void RenderToTextureStage::reset()
 
 void RenderToTextureStage::draw(osg::State& state,RenderLeaf*& previous)
 {
+    
+    if (_stageDrawnThisFrame) return;
+
+    //cout << "begining RTTS draw "<<this<< "  "<<_viewport->x()<<","<< _viewport->y()<<","<< _viewport->width()<<","<< _viewport->height()<<std::endl;
 
     RenderStage::draw(state,previous);
 
     // now copy the rendered image to attached texture.
     if (_texture.valid())
+    {
+        //cout << "        reading "<<this<< "  "<<_viewport->x()<<","<< _viewport->y()<<","<< _viewport->width()<<","<< _viewport->height()<<std::endl;
+
         _texture->copyTexImage2D(state,_viewport->x(),_viewport->y(),_viewport->width(),_viewport->height());
+    }
     
     if (_image.valid())
         _image->readPixels(_viewport->x(),_viewport->y(),_viewport->width(),_viewport->height(),GL_RGBA,GL_UNSIGNED_BYTE);