Merge pull request #2893 from ZappoMan/master

fix crash in model server when you attempt to create an unreasonably small model

libraries/models/src/ModelTreeElement.cpp

@@ -95,6 +95,11 @@ bool ModelTreeElement::bestFitModelBounds(const ModelItem& model) const {
     if (_box.contains(clampedMin) && _box.contains(clampedMax)) {
         int childForMinimumPoint = getMyChildContainingPoint(clampedMin);
         int childForMaximumPoint = getMyChildContainingPoint(clampedMax);
+        
+        // if this is a really small box, then it's close enough!
+        if (_box.getScale() <= SMALLEST_REASONABLE_OCTREE_ELEMENT_SCALE) {
+            return true;
+        }
         // If I contain both the minimum and maximum point, but two different children of mine
         // contain those points, then I am the best fit for that model
         if (childForMinimumPoint != childForMaximumPoint) {

libraries/octree/src/OctreeElement.cpp

@@ -1412,6 +1412,11 @@ OctreeElement* OctreeElement::getOrCreateChildElementContaining(const AABox& box
     if (!child) {
         child = addChildAtIndex(childIndex);
     }
+    
+    // if we've made a really small child, then go ahead and use that one.
+    if (child->getScale() <= SMALLEST_REASONABLE_OCTREE_ELEMENT_SCALE) {
+        return child;
+    }
 
     // Now that we have the child to recurse down, let it answer the original question...
     return child->getOrCreateChildElementContaining(box);

libraries/octree/src/OctreeElement.h

@@ -32,6 +32,8 @@ class OctreePacketData;
 class ReadBitstreamToTreeParams;
 class VoxelSystem;
 
+const float SMALLEST_REASONABLE_OCTREE_ELEMENT_SCALE = (1.0f / TREE_SCALE) / 10000.0f; // 1/10,000th of a meter
+
 // Callers who want delete hook callbacks should implement this class
 class OctreeElementDeleteHook {
 public: