From d121c8e07af33811b5ac636a00a2b4635c38c5de Mon Sep 17 00:00:00 2001
From: Andrzej Kapolka <drzej.k@gmail.com>
Date: Thu, 10 Jul 2014 17:21:05 -0700
Subject: [PATCH] Fix for starting with empty spanners (due to LOD), then
 adding.

---
 libraries/metavoxels/src/AttributeRegistry.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libraries/metavoxels/src/AttributeRegistry.cpp b/libraries/metavoxels/src/AttributeRegistry.cpp
index b43759fa4f..64b2646261 100644
--- a/libraries/metavoxels/src/AttributeRegistry.cpp
+++ b/libraries/metavoxels/src/AttributeRegistry.cpp
@@ -568,6 +568,10 @@ void SpannerSetAttribute::readMetavoxelRoot(MetavoxelData& data, MetavoxelStream
         }
         data.insert(state.attribute, object);
     }
+    // even if the root is empty, it should still exist
+    if (!data.getRoot(state.attribute)) {
+        data.createRoot(state.attribute);
+    }
 }
 
 void SpannerSetAttribute::writeMetavoxelRoot(const MetavoxelNode& root, MetavoxelStreamState& state) {
@@ -586,6 +590,10 @@ void SpannerSetAttribute::readMetavoxelDelta(MetavoxelData& data,
         }
         data.toggle(state.attribute, object);
     }
+    // even if the root is empty, it should still exist
+    if (!data.getRoot(state.attribute)) {
+        data.createRoot(state.attribute);
+    }
 }
 
 void SpannerSetAttribute::writeMetavoxelDelta(const MetavoxelNode& root,