From 66f0e0d8e8bd8983897d214ccd91a806c39d8612 Mon Sep 17 00:00:00 2001
From: Tom Payne <twpayne@gmail.com>
Date: Mon, 8 Apr 2013 21:19:19 +0200
Subject: [PATCH] Add optimized version of getTileCoordChildTileRange for
 ol.tilegrid.XYZ

---
 src/ol/tilegrid/xyztilegrid.js | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/ol/tilegrid/xyztilegrid.js b/src/ol/tilegrid/xyztilegrid.js
index 41670261ad..72572417fb 100644
--- a/src/ol/tilegrid/xyztilegrid.js
+++ b/src/ol/tilegrid/xyztilegrid.js
@@ -39,6 +39,20 @@ ol.tilegrid.XYZ = function(options) {
 goog.inherits(ol.tilegrid.XYZ, ol.tilegrid.TileGrid);
 
 
+/**
+ * @inheritDoc
+ */
+ol.tilegrid.XYZ.prototype.getTileCoordChildTileRange = function(tileCoord) {
+  if (tileCoord.z < this.maxZoom_) {
+    return new ol.TileRange(
+        tileCoord.x << 1, tileCoord.y << 1,
+        tileCoord.x + 1 << 1, tileCoord.y + 1 << 1);
+  } else {
+    return null;
+  }
+};
+
+
 /**
  * @inheritDoc
  */