Refactor Tileset Traversal

Source/Scene/Cesium3DTile.js

@@ -330,16 +330,20 @@ define([
          */
         this._optimChildrenWithinParent = Cesium3DTileOptimizationHint.NOT_COMPUTED;
 
-        this._sse = 0;
+        this._screenSpaceError = 0;
+        this._screenSpaceErrorComputedFrame = -1;
         this._finalResolution = true;
         this._requestHeap = undefined;
         this._depth = 0;
         this._centerZDepth = 0;
         this._stackLength = 0;
         this._selectedFrame = -1;
         this._selectionDepth = 0;
-        this._lastFinalResolution = undefined;
         this._lastSelectionDepth = undefined;
+        this._requestedFrame = undefined;
+        this._lastVisitedFrame = undefined;
+        this._ancestorWithContent = undefined;
+        this._ancestorWithLoadedContent = undefined;
     }
 
     defineProperties(Cesium3DTile.prototype, {

Source/Scene/Cesium3DTileBatchTable.js

@@ -1261,13 +1261,13 @@ define([
                 derivedCommands.front = deriveTranslucentCommand(command, CullFace.BACK);
             }
 
-            var bivariateVisibilityTest = tileset._hasMixedContent && this.context.stencilBuffer;
+            var bivariateVisibilityTest = tileset.skipLODs && tileset._hasMixedContent && this.context.stencilBuffer;
 
             if (bivariateVisibilityTest) {
-                if (!tile._finalResolution) {
-                    if (!defined(derivedCommands.zback)) {
-                        derivedCommands.zback = deriveZBackfaceCommand(command);
-                    }
+                if (!defined(derivedCommands.zback)) {
+                    derivedCommands.zback = deriveZBackfaceCommand(command);
+                }
+                if (command.pass !== Pass.TRANSLUCENT) {
                     tileset._backfaceCommands.push(derivedCommands.zback);
                 }
 
@@ -1340,13 +1340,16 @@ define([
 
     function deriveCommand(command) {
         var derivedCommand = DrawCommand.shallowClone(command);
-        derivedCommand.pass = Pass.CESIUM_3D_TILE;
 
         // Add a uniform to indicate if the original command was translucent so
         // the shader knows not to cull vertices that were originally transparent
         // even though their style is opaque.
         var translucentCommand = (derivedCommand.pass === Pass.TRANSLUCENT);
 
+        if (!translucentCommand) {
+            derivedCommand.pass = Pass.CESIUM_3D_TILE;
+        }
+
         derivedCommand.uniformMap = defined(derivedCommand.uniformMap) ? derivedCommand.uniformMap : {};
         derivedCommand.uniformMap.tile_translucentCommand = function() {
             return translucentCommand;