From 51dfe894258663e5f13e842ae261c5b7ed4ab0b6 Mon Sep 17 00:00:00 2001
From: Tim Schaub <tim.schaub@gmail.com>
Date: Fri, 18 Mar 2016 16:27:40 -0600
Subject: [PATCH] Add assert message

---
 src/ol/render/canvas/canvasimmediate.js | 2 +-
 src/ol/render/webgl/webglimmediate.js   | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/ol/render/canvas/canvasimmediate.js b/src/ol/render/canvas/canvasimmediate.js
index d26a7be9c6..8d04244890 100644
--- a/src/ol/render/canvas/canvasimmediate.js
+++ b/src/ol/render/canvas/canvasimmediate.js
@@ -541,7 +541,7 @@ ol.render.canvas.Immediate.prototype.drawFeature = function(feature, style) {
     render.setFillStrokeStyle(style.getFill(), style.getStroke());
     render.setImageStyle(style.getImage());
     render.setTextStyle(style.getText());
-    goog.asserts.assert(geometry);
+    goog.asserts.assert(geometry, 'geometry must be truthy');
     render.drawGeometry(geometry);
   });
 };
diff --git a/src/ol/render/webgl/webglimmediate.js b/src/ol/render/webgl/webglimmediate.js
index c586a356e1..c848d17928 100644
--- a/src/ol/render/webgl/webglimmediate.js
+++ b/src/ol/render/webgl/webglimmediate.js
@@ -164,7 +164,7 @@ ol.render.webgl.Immediate.prototype.drawFeature = function(feature, style) {
   }
   this.drawAsync(zIndex, function(render) {
     render.setStyle(style);
-    goog.asserts.assert(geometry);
+    goog.asserts.assert(geometry, 'geometry must be truthy');
     render.drawGeometry(geometry);
   });
 };