SL-17244 Fix 'empty leaf' crashes

indra/llmath/lloctree.h

@@ -73,7 +73,7 @@ template <class T>
 class LLOctreeTravelerDepthFirst : public LLOctreeTraveler<T>
 {
 public:
-	virtual void traverse(const LLOctreeNode<T>* node);
+	virtual void traverse(const LLOctreeNode<T>* node) override;
 };
 
 template <class T>
@@ -696,7 +696,7 @@ public:
 	{
 	}
 	
-	bool balance()
+	bool balance() override
 	{	
         //LL_PROFILE_ZONE_NAMED_COLOR("Octree::balance()",OCTREE_DEBUG_COLOR_BALANCE);
 
@@ -732,7 +732,7 @@ public:
 	}
 
 	// LLOctreeRoot::insert
-	bool insert(T* data)
+	bool insert(T* data) override
 	{
 		if (data == NULL) 
 		{
@@ -835,6 +835,12 @@ public:
 
 		return false;
 	}
+
+    bool isLeaf() const override
+    {
+        // root can't be a leaf
+        return false;
+    }
 };
 
 //========================

indra/llmath/llvolume.cpp

@@ -414,7 +414,7 @@ public:
 				max.setMax(max, *tri->mV[2]);
 			}
 		}
-		else if (!branch->isLeaf())
+		else if (branch->getChildCount() > 0)
 		{ //no data, but child nodes exist
 			LLVolumeOctreeListener* child = (LLVolumeOctreeListener*) branch->getChild(0)->getListener(0);
 
@@ -424,7 +424,7 @@ public:
 		}
 		else
 		{
-			LL_ERRS() << "Empty leaf" << LL_ENDL;
+            llassert(!branch->isLeaf()); // Empty leaf
 		}
 
 		for (S32 i = 0; i < branch->getChildCount(); ++i)

indra/newview/llvieweroctree.cpp

@@ -564,7 +564,7 @@ void LLViewerOctreeGroup::rebound()
 		
 		group->setState(SKIP_FRUSTUM_CHECK);
 	}
-	else if (mOctreeNode->isLeaf())
+	else if (mOctreeNode->getChildCount() == 0)
 	{ //copy object bounding box if this is a leaf
 		boundObjects(TRUE, mExtents[0], mExtents[1]);
 		mBounds[0] = mObjectBounds[0];