Merge pull request #7011 from AnalyticalGraphicsInc/refinement-fix

Fix tileset traversal
CesiumGS · Sep 10, 2018 · 798ff75 · 798ff75
2 parents d6ad77b + 5fd4805
commit 798ff75
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Showing 3 changed files with 46 additions and 17 deletions.
diff --git a/CHANGES.md b/CHANGES.md
@@ -6,6 +6,9 @@ Change Log
 ##### Additions :tada:
 * Added `cartographicLimitRectangle` to `Globe`. Use this to limit terrain and imagery to a specific `Rectangle` area. [#6987](https://github.com/AnalyticalGraphicsInc/cesium/pull/6987)
 
+##### Fixes :wrench:
+* Fixed an issue in the 3D Tiles traversal where empty tiles would be selected instead of their nearest loaded ancestors. [#7011](https://github.com/AnalyticalGraphicsInc/cesium/pull/7011)
+
 ### 1.49 - 2018-09-04
 
 ##### Breaking Changes :mega:

diff --git a/Source/Scene/Cesium3DTilesetTraversal.js b/Source/Scene/Cesium3DTilesetTraversal.js
@@ -156,13 +156,15 @@ define([
             var childrenLength = children.length;
             for (var i = 0; i < childrenLength; ++i) {
                 var child = children[i];
-                if (child.contentAvailable) {
-                    updateTile(tileset, child, frameState);
-                    touchTile(tileset, child, frameState);
-                    selectTile(tileset, child, frameState);
-                } else if (child._depth - root._depth < descendantSelectionDepth) {
-                    // Continue traversing, but not too far
-                    stack.push(child);
+                if (isVisible(child)) {
+                    if (child.contentAvailable) {
+                        updateTile(tileset, child, frameState);
+                        touchTile(tileset, child, frameState);
+                        selectTile(tileset, child, frameState);
+                    } else if (child._depth - root._depth < descendantSelectionDepth) {
+                        // Continue traversing, but not too far
+                        stack.push(child);
+                    }
                 }
             }
         }
@@ -469,11 +471,17 @@ define([
                 refines = updateAndPushChildren(tileset, tile, stack, frameState) && parentRefines;
             }
 
+            var stoppedRefining = !refines && parentRefines;
+
             if (hasEmptyContent(tile)) {
                 // Add empty tile just to show its debug bounding volume
                 // If the tile has tileset content load the external tileset
+                // If the tile cannot refine further select its nearest loaded ancestor
                 addEmptyTile(tileset, tile, frameState);
                 loadTile(tileset, tile, frameState);
+                if (stoppedRefining) {
+                    selectDesiredTile(tileset, tile, frameState);
+                }
             } else if (add) {
                 // Additive tiles are always loaded and selected
                 selectDesiredTile(tileset, tile, frameState);
@@ -483,18 +491,16 @@ define([
                     // Always load tiles in the base traversal
                     // Select tiles that can't refine further
                     loadTile(tileset, tile, frameState);
-                    if (!refines && parentRefines) {
+                    if (stoppedRefining) {
                         selectDesiredTile(tileset, tile, frameState);
                     }
-                } else {
-                    // Load tiles that are not skipped or can't refine further. In practice roughly half the tiles stay unloaded.
-                    // Select tiles that can't refine further. If the tile doesn't have loaded content it will try to select an ancestor with loaded content instead.
-                    if (!refines) { // eslint-disable-line
-                        selectDesiredTile(tileset, tile, frameState);
-                        loadTile(tileset, tile, frameState);
-                    } else if (reachedSkippingThreshold(tileset, tile)) {
-                        loadTile(tileset, tile, frameState);
-                    }
+                } else if (stoppedRefining) {
+                    // In skip traversal, load and select tiles that can't refine further
+                    selectDesiredTile(tileset, tile, frameState);
+                    loadTile(tileset, tile, frameState);
+                } else if (reachedSkippingThreshold(tileset, tile)) {
+                    // In skip traversal, load tiles that aren't skipped. In practice roughly half the tiles stay unloaded.
+                    loadTile(tileset, tile, frameState);
                 }
             }
 

diff --git a/Specs/Scene/Cesium3DTilesetSpec.js b/Specs/Scene/Cesium3DTilesetSpec.js
@@ -1070,6 +1070,26 @@ defineSuite([
         });
     });
 
+    it('replacement refinement - selects upwards when traversal stops at empty tile', function() {
+        // No children have content, but all grandchildren have content
+        //
+        //          C
+        //      E       E
+        //    C   C   C   C
+        //
+        return Cesium3DTilesTester.loadTileset(scene, tilesetReplacement1Url).then(function(tileset) {
+            tileset.root.geometricError = 90;
+            viewRootOnly();
+            scene.camera.zoomIn(20);
+            scene.renderForSpecs();
+
+            var statistics = tileset._statistics;
+            expect(statistics.selected).toEqual(1);
+            expect(statistics.visited).toEqual(3);
+            expect(isSelected(tileset, tileset.root)).toBe(true);
+        });
+    });
+
     it('replacement refinement - selects root when sse is not met and subtree is not refinable (1)', function() {
         // No children have content, but all grandchildren have content
         //