Use the average of the three triangle vertices (rather than the first

vertex) to compute the depth used for sorting.  There are still annoying 
artifacts, but I've already spent too much time exploring all the ways 
to sort these things.


git-svn-id: svn+ssh://src.earth.threerings.net/nenya/trunk@31 ed5b42cb-e716-0410-a449-f6a68f950b19

src/java/com/threerings/jme/tools/ModelViewer.java

@@ -366,6 +366,7 @@ public class ModelViewer extends JmeCanvasApp
     {
         super.initDisplay();
         _ctx.getRenderer().setBackgroundColor(ColorRGBA.gray);
+        _ctx.getRenderer().getQueue().setTwoPassTransparency(false);
     }
     
     @Override // documentation inherited