Wait until both head and body are loaded before rendering. Closes #2145.

interface/src/avatar/Avatar.cpp

@@ -309,6 +309,9 @@ void Avatar::renderBody() {
         renderBillboard();
         return;
     }
+    if (!(_skeletonModel.isRenderable() && getHead()->getFaceModel().isRenderable())) {
+        return; // wait until both models are loaded
+    }
     _skeletonModel.render(1.0f);
     getHead()->render(1.0f);
     getHand()->render(false);

interface/src/avatar/MyAvatar.cpp

@@ -677,6 +677,10 @@ void MyAvatar::setSkeletonModelURL(const QUrl& skeletonModelURL) {
 }
 
 void MyAvatar::renderBody(bool forceRenderHead) {
+    if (!(_skeletonModel.isRenderable() && getHead()->getFaceModel().isRenderable())) {
+        return; // wait until both models are loaded
+    }
+    
     //  Render the body's voxels and head
     _skeletonModel.render(1.0f);
 

interface/src/renderer/Model.h

@@ -46,6 +46,8 @@ public:
     
     bool isActive() const { return _geometry && _geometry->isLoaded(); }
     
+    bool isRenderable() const { return !_meshStates.isEmpty(); }
+    
     bool isLoadedWithTextures() const;
     
     void init();