From a421943eb1d4c880ad845becd7d5b7fe558a884c Mon Sep 17 00:00:00 2001
From: Tom Payne <twpayne@gmail.com>
Date: Wed, 18 Jul 2012 00:09:54 +0200
Subject: [PATCH] Clear framebuffer before writing tiles

---
 src/ol/webgl/tilelayerrenderer.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/ol/webgl/tilelayerrenderer.js b/src/ol/webgl/tilelayerrenderer.js
index 216d324747..a3407dc4ee 100644
--- a/src/ol/webgl/tilelayerrenderer.js
+++ b/src/ol/webgl/tilelayerrenderer.js
@@ -269,6 +269,8 @@ ol.webgl.TileLayerRenderer.prototype.redraw = function() {
     gl.bindFramebuffer(goog.webgl.FRAMEBUFFER, this.framebuffer_);
   }
 
+  gl.clearColor(0, 0, 0, 0);
+  gl.clear(goog.webgl.COLOR_BUFFER_BIT);
   gl.disable(goog.webgl.BLEND);
 
   var program = map.getProgram(this.fragmentShader_, this.vertexShader_);