fix missing fog

src/game-lib-d3-api-scene.js

@@ -69,7 +69,7 @@ GameLib.D3.API.Scene = function(
     this.images = images;
 
     if (GameLib.Utils.UndefinedOrNull(fog)) {
-        fog = null;
+        fog = new GameLib.D3.API.Fog();
     }
     this.fog = fog;
 

src/game-lib-d3-geometry-buffer-a.js

@@ -330,7 +330,11 @@ GameLib.D3.Geometry.Buffer.prototype.toApiObject = function() {
         this.drawRange.toApiObject(),
         this.groups.map(
             function(group){
-                return group.toApiObject()
+                if (group instanceof GameLib.Group) {
+                    return group.toApiObject();
+                } else {
+                    return group;
+                }
             }
         ),
         null,   //index,