From e079c1941319aeba5bc14d8750b351d3ba4318d7 Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Wed, 6 Feb 2013 16:10:46 -0700
Subject: [PATCH] Don't repeatedly render while waiting for tiles to load

Instead of going into an unnecessary animation loop, we can simply wait to be notified when tiles load.

The WebGL renderer still sets frameState.animate true, but I think this too should be unnecessary (full page example works without it, side-by-side example shows it cannot yet be removed).
---
 src/ol/renderer/canvas/canvastilelayerrenderer.js |  6 ++----
 src/ol/renderer/dom/domtilelayerrenderer.js       |  6 ++----
 src/ol/renderer/layerrenderer.js                  | 15 +++++++++++++++
 src/ol/renderer/webgl/webgltilelayerrenderer.js   |  2 ++
 4 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/src/ol/renderer/canvas/canvastilelayerrenderer.js b/src/ol/renderer/canvas/canvastilelayerrenderer.js
index c2987af91b..da9ef99a2b 100644
--- a/src/ol/renderer/canvas/canvastilelayerrenderer.js
+++ b/src/ol/renderer/canvas/canvastilelayerrenderer.js
@@ -167,6 +167,8 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
 
       tileState = tile.getState();
       if (tileState == ol.TileState.IDLE) {
+        goog.events.listen(tile, goog.events.EventType.CHANGE,
+            this.handleTileChange, false, this);
         this.updateWantedTiles(frameState.wantedTiles, tileSource, tileCoord);
         tileCenter = tileGrid.getTileCoordCenter(tileCoord);
         frameState.tileQueue.enqueue(tile, tileSourceKey, tileCenter);
@@ -215,10 +217,6 @@ ol.renderer.canvas.TileLayer.prototype.renderFrame =
     }
   }
 
-  if (!allTilesLoaded) {
-    frameState.animate = true;
-  }
-
   this.updateUsedTiles(frameState.usedTiles, tileSource, z, tileRange);
   this.scheduleExpireCache(frameState, tileSource);
 
diff --git a/src/ol/renderer/dom/domtilelayerrenderer.js b/src/ol/renderer/dom/domtilelayerrenderer.js
index 0676d629d6..537ff16e52 100644
--- a/src/ol/renderer/dom/domtilelayerrenderer.js
+++ b/src/ol/renderer/dom/domtilelayerrenderer.js
@@ -131,6 +131,8 @@ ol.renderer.dom.TileLayer.prototype.renderFrame =
 
       tileState = tile.getState();
       if (tileState == ol.TileState.IDLE) {
+        goog.events.listen(tile, goog.events.EventType.CHANGE,
+            this.handleTileChange, false, this);
         this.updateWantedTiles(frameState.wantedTiles, tileSource, tileCoord);
         tileCenter = tileGrid.getTileCoordCenter(tileCoord);
         frameState.tileQueue.enqueue(tile, tileSourceKey, tileCenter);
@@ -233,10 +235,6 @@ ol.renderer.dom.TileLayer.prototype.renderFrame =
     this.renderedVisible_ = true;
   }
 
-  if (!allTilesLoaded) {
-    frameState.animate = true;
-  }
-
   this.updateUsedTiles(frameState.usedTiles, tileSource, z, tileRange);
   this.scheduleExpireCache(frameState, tileSource);
 
diff --git a/src/ol/renderer/layerrenderer.js b/src/ol/renderer/layerrenderer.js
index 982a454d72..fab64889fc 100644
--- a/src/ol/renderer/layerrenderer.js
+++ b/src/ol/renderer/layerrenderer.js
@@ -4,8 +4,10 @@ goog.require('goog.events');
 goog.require('goog.events.EventType');
 goog.require('ol.FrameState');
 goog.require('ol.Object');
+goog.require('ol.Tile');
 goog.require('ol.TileCoord');
 goog.require('ol.TileRange');
+goog.require('ol.TileState');
 goog.require('ol.layer.Layer');
 goog.require('ol.layer.LayerProperty');
 goog.require('ol.layer.LayerState');
@@ -147,6 +149,19 @@ ol.renderer.Layer.prototype.handleLayerVisibleChange = function() {
 };
 
 
+/**
+ * Handle changes in tile state.
+ * @param {goog.events.Event} event Tile change event.
+ * @protected
+ */
+ol.renderer.Layer.prototype.handleTileChange = function(event) {
+  var tile = /** @type {ol.Tile} */ (event.target);
+  if (tile.getState() === ol.TileState.LOADED) {
+    this.getMap().requestRenderFrame();
+  }
+};
+
+
 /**
  * @param {ol.FrameState} frameState Frame state.
  * @param {ol.layer.LayerState} layerState Layer state.
diff --git a/src/ol/renderer/webgl/webgltilelayerrenderer.js b/src/ol/renderer/webgl/webgltilelayerrenderer.js
index 77cf37aa79..068a9687c3 100644
--- a/src/ol/renderer/webgl/webgltilelayerrenderer.js
+++ b/src/ol/renderer/webgl/webgltilelayerrenderer.js
@@ -393,6 +393,8 @@ ol.renderer.webgl.TileLayer.prototype.renderFrame =
 
         tileState = tile.getState();
         if (tileState == ol.TileState.IDLE) {
+          goog.events.listen(tile, goog.events.EventType.CHANGE,
+              this.handleTileChange, false, this);
           this.updateWantedTiles(frameState.wantedTiles, tileSource, tileCoord);
           tileCenter = tileGrid.getTileCoordCenter(tileCoord);
           frameState.tileQueue.enqueue(tile, tileSourceKey, tileCenter);