Minor tweaks to reverseZ code.

CHANGES.md

@@ -14,6 +14,7 @@ Change Log
 * Added support for `GroundPrimitive` which works much like `Primitive` but it drapes the geometry over terrain. Valid geometries that can be draped on terrain are `CircleGeometry`, `CorridorGeometry`, `EllipseGeometry`, `PolygonGeometry`, and `RectangleGeometry`.
 * Added `BoundingSphere.isOccluded` and `OrientedBoundingBox.isOccluded` to determine if the volumes are occluded by an `Occluder`.
 * Added `distanceSquaredTo` and `computePlaneDistances` functions to `OrientedBoundingBox`.
+* Added `reverseZ` tag to `UrlTemplateImageryProvider`.
 
 ### 1.12 - 2015-08-03
 

Source/Scene/UrlTemplateImageryProvider.js

@@ -62,6 +62,7 @@ define([
      *     <li><code>{s}</code>: One of the available subdomains, used to overcome browser limits on the number of simultaneous requests per host.</li>
      *     <li><code>{reverseX}</code>: The tile X coordinate in the tiling scheme, where 0 is the Easternmost tile.</li>
      *     <li><code>{reverseY}</code>: The tile Y coordinate in the tiling scheme, where 0 is the Southernmost tile.</li>
+     *     <li><code>{reverseZ}</code>: The level of the tile in the tiling scheme, where level zero is the maximum level of the quadtree pyramid.  In order to use reverseZ, maximumLevel must be defined.</li>
      *     <li><code>{westDegrees}</code>: The Western edge of the tile in geodetic degrees.</li>
      *     <li><code>{southDegrees}</code>: The Southern edge of the tile in geodetic degrees.</li>
      *     <li><code>{eastDegrees}</code>: The Eastern edge of the tile in geodetic degrees.</li>
@@ -201,6 +202,7 @@ define([
          *  <li> <code>{s}</code>: One of the available subdomains, used to overcome browser limits on the number of simultaneous requests per host.</li>
          *  <li> <code>{reverseX}</code>: The tile X coordinate in the tiling scheme, where 0 is the Easternmost tile.</li>
          *  <li> <code>{reverseY}</code>: The tile Y coordinate in the tiling scheme, where 0 is the Southernmost tile.</li>
+         *  <li> <code>{reverseZ}</code>: The level of the tile in the tiling scheme, where level zero is the maximum level of the quadtree pyramid.  In order to use reverseZ, maximumLevel must be defined.</li>
          *  <li> <code>{westDegrees}</code>: The Western edge of the tile in geodetic degrees.</li>
          *  <li> <code>{southDegrees}</code>: The Southern edge of the tile in geodetic degrees.</li>
          *  <li> <code>{eastDegrees}</code>: The Eastern edge of the tile in geodetic degrees.</li>
@@ -598,6 +600,11 @@ define([
         return imageryProvider.tilingScheme.getNumberOfYTilesAtLevel(level) - y - 1;
     }
 
+    function reverseZTag(imageryProvider, x, y, level) {
+        var maximumLevel = imageryProvider.maximumLevel;
+        return defined(maximumLevel) && level < maximumLevel ? maximumLevel - level - 1 : level;
+    }
+
     function zTag(imageryProvider, x, y, level) {
         return level;
     }
@@ -777,6 +784,7 @@ define([
         '{s}': sTag,
         '{reverseX}': reverseXTag,
         '{reverseY}': reverseYTag,
+        '{reverseZ}': reverseZTag,
         '{westDegrees}': westDegreesTag,
         '{southDegrees}': southDegreesTag,
         '{eastDegrees}': eastDegreesTag,

Specs/Scene/UrlTemplateImageryProviderSpec.js

@@ -223,17 +223,18 @@ defineSuite([
         });
     });
 
-    it('evaluation of pattern X Y reverseX reverseY Z', function() {
+    it('evaluation of pattern X Y reverseX reverseY Z reverseZ', function() {
         var provider = new UrlTemplateImageryProvider({
-            url: 'made/up/tms/server/{z}/{reverseY}/{y}/{reverseX}/{x}.PNG',
-            tilingScheme: new GeographicTilingScheme()
+            url: 'made/up/tms/server/{z}/{reverseZ}/{reverseY}/{y}/{reverseX}/{x}.PNG',
+            tilingScheme: new GeographicTilingScheme(),
+            maximumLevel: 6
         });
 
         return pollToPromise(function() {
             return provider.ready;
         }).then(function() {
             spyOn(loadImage, 'createImage').and.callFake(function(url, crossOrigin, deferred) {
-                expect(url).toEqual('made/up/tms/server/2/2/1/4/3.PNG');
+                expect(url).toEqual('made/up/tms/server/2/3/2/1/4/3.PNG');
 
                 // Just return any old image.
                 loadImage.defaultCreateImage('Data/Images/Red16x16.png', crossOrigin, deferred);