Modify the GLObjectPool to defer GL object deletion by a frame in ord…

…er to ensure that objects don't get deleted before their final use in the rendering thread

src/osgEarth/GLUtils

@@ -563,12 +563,14 @@ namespace osgEarth
 
     /**
      * Mechanism that will automatically delete a GL object
-     * when its container goes out of scope
+     * when its container goes out of scope. The object pool uses 
+     * a deferred deletion policy (of one frame) to ensure an object
+     * is not deleted before the GL pipeline has finished using it.
      */
     class OSGEARTH_EXPORT GLObjectPool : public osg::GraphicsObjectManager
     {
     public:
-        using Collection = std::vector< GLObject::Ptr >;
+        using Collection = std::vector<GLObject::Ptr>;
 
         //! construct an object pool under the given graphics context ID
         GLObjectPool(unsigned contextID);
@@ -627,7 +629,8 @@ namespace osgEarth
     protected:
 
         mutable Mutex _mutex;
-        Collection _objects;
+        Collection _objects; // objects being monitored
+        Collection _orphans; // objects whose refcount has dropped to 1
         GLsizeiptr _totalBytes;
         unsigned _hits;
         unsigned _misses;

src/osgEarth/GLUtils.cpp

@@ -726,30 +726,43 @@ GLObjectPool::releaseOrphans(const osg::GraphicsContext* gc)
 {
     ScopedMutexLock lock(_mutex);
 
-    GLsizeiptr bytes = 0;
     unsigned maxNumToRelease = std::max(1u, (unsigned)pow(4.0f, _avarice));
     unsigned numReleased = 0u;
 
-    for (unsigned int i = 0; i < _objects.size();)
+    // first go thru and release some orphans.
+    Collection orphans_to_keep;
+    for (unsigned i = 0; i < _orphans.size() && numReleased < maxNumToRelease; ++i)
     {
-        GLObject::Ptr& object = _objects[i];
-
-        if (object->gc() == gc && object.use_count() == 1 && numReleased < maxNumToRelease)
+        GLObject::Ptr& object = _orphans[i];
+        if (object->gc() == gc)
         {
-            // Release the object
             object->release();
             ++numReleased;
-            // Move the object at the end of the vector into this slot, making sure not to increment i as we want this object processed next.
-            _objects[i] = std::move(_objects.back());
-            // Reduce the size of the vector by 1.
-            _objects.resize(_objects.size() - 1);
         }
         else
         {
+            orphans_to_keep.push_back(object);
+        }
+    }
+    _orphans.swap(orphans_to_keep);
+
+    // then check for objects to add to the orphan list:
+    GLsizeiptr bytes = 0;
+    Collection objects_to_keep;
+    objects_to_keep.reserve(_objects.size());
+    for(auto& object : _objects)
+    {
+        if (object->gc() == gc && object.use_count() == 1)
+        {
+            _orphans.push_back(object);
+        }
+        else
+        {
+            objects_to_keep.push_back(object);
             bytes += object->size();
-            ++i;
         }
     }
+    _objects.swap(objects_to_keep);
     _totalBytes = bytes;
 }
 

src/osgEarth/TextureArena

@@ -210,7 +210,7 @@ namespace osgEarth
         mutable osg::buffered_object<GLObjects> _globjects;
 
         mutable TextureVector _textures;
-        mutable std::unordered_map<Texture::Ptr, unsigned int> _textureIndices;
+        mutable std::unordered_map<Texture*, unsigned> _textureIndices;
         mutable std::unordered_set<unsigned> _dynamicTextures;
 
         bool _autoRelease = false;

src/osgEarth/TextureArena.cpp

@@ -568,7 +568,7 @@ TextureArena::find_no_lock(Texture::Ptr tex) const
     if (tex == nullptr)
         return -1;
 
-    auto itr = _textureIndices.find(tex);
+    auto itr = _textureIndices.find(tex.get());
     if (itr != _textureIndices.end())
     {
         return itr->second;
@@ -690,7 +690,7 @@ TextureArena::add(Texture::Ptr tex, const osgDB::Options* readOptions)
     int index = -1;
 
     // find an open slot if one is available:
-    if (_autoRelease == true)
+    //if (_autoRelease == true)
     {
         for (int i = 0; i < _textures.size(); ++i)
         {
@@ -720,7 +720,7 @@ TextureArena::add(Texture::Ptr tex, const osgDB::Options* readOptions)
     else
         _textures.push_back(tex);
 
-    _textureIndices[tex] = index;
+    _textureIndices[tex.get()] = index;
 
     if (tex->osgTexture()->getDataVariance() == osg::Object::DYNAMIC)
     {
@@ -737,12 +737,11 @@ TextureArena::purgeTextureIfOrphaned_no_lock(unsigned index)
 
     Texture::Ptr& tex = _textures[index];
 
-    // Check for use_count() == 2.
-    // 1 for the _textures vector and 1 for the _textureIndices map.
-    if (tex && tex.use_count() == 2)
+    // Check for use_count() == 1, meaning that the only reference to this
+    if (tex && tex.use_count() == 1)
     {
         // Remove this texture from the texture indices map
-        _textureIndices.erase(tex);
+        _textureIndices.erase(tex.get());
 
         // Remove this texture from the collection of dynamic textures
         _dynamicTextures.erase(index);

src/osgEarthDrivers/engine_rex/LayerDrawable

@@ -95,7 +95,7 @@ namespace osgEarth { namespace REX
         bool supports(const osg::PrimitiveIndexFunctor&) const override { return true; }
         void accept(osg::PrimitiveIndexFunctor&) const override;
 
-        virtual void accept(osg::NodeVisitor& nv) override {
+        void accept(osg::NodeVisitor& nv) override {
             osg::Drawable::accept(nv);
         }
 
@@ -143,10 +143,10 @@ namespace osgEarth { namespace REX
 
     public: // osg::Drawable
 
-        virtual void drawImplementation(osg::RenderInfo& ri) const override;
-        virtual void releaseGLObjects(osg::State*) const override;
-        virtual void resizeGLObjectBuffers(unsigned size) override;
-        virtual void accept(osg::NodeVisitor& nv) override;
+        void drawImplementation(osg::RenderInfo& ri) const override;
+        void releaseGLObjects(osg::State*) const override;
+        void resizeGLObjectBuffers(unsigned size) override;
+        void accept(osg::NodeVisitor& nv) override;
 
     protected:
 

src/osgEarthDrivers/engine_rex/LayerDrawable.cpp

@@ -135,6 +135,10 @@ LayerDrawableNVGL::LayerDrawableNVGL() :
     LayerDrawable()
 {
     setName("LayerDrawableNVGL");
+
+    // Make sure our structures are aligned to 16 bytes
+    OE_HARD_ASSERT(sizeof(GL4GlobalData) % 16 == 0);
+    OE_HARD_ASSERT(sizeof(GL4Tile) % 16 == 0);
 }
 LayerDrawableNVGL::~LayerDrawableNVGL()
 {
@@ -503,7 +507,7 @@ LayerDrawableNVGL::drawImplementation(osg::RenderInfo& ri) const
         GLenum element_type =
             sizeof(DrawElementsBase::value_type) == sizeof(short) ?
             GL_UNSIGNED_SHORT : GL_UNSIGNED_INT;
-        
+
         gl.glMultiDrawElementsIndirectBindlessNV(
             primitive_type,
             element_type,

src/osgEarthDrivers/engine_rex/RexTerrainEngineNode.cpp

@@ -1027,10 +1027,12 @@ RexTerrainEngineNode::update_traverse(osg::NodeVisitor& nv)
     }
     _persistent.unlock();
 
+#if 1
     // traverse the texture arena since it's not in the scene graph.
     auto* arena = getEngineContext()->textures();
     if (arena)
         arena->update(nv);
+#endif
 }
 
 void