From 3e56dba1b45c942d22ed2c7786f5e58629e8ecc9 Mon Sep 17 00:00:00 2001
From: GaborFarkas <raandal73@gmail.com>
Date: Wed, 16 Nov 2016 12:54:05 +0100
Subject: [PATCH] Do not draw vectors outside viewport

---
 src/ol/renderer/webgl/vectorlayer.js | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/ol/renderer/webgl/vectorlayer.js b/src/ol/renderer/webgl/vectorlayer.js
index 035cb76ad1..494d5eb149 100644
--- a/src/ol/renderer/webgl/vectorlayer.js
+++ b/src/ol/renderer/webgl/vectorlayer.js
@@ -73,11 +73,17 @@ ol.renderer.webgl.VectorLayer.prototype.composeFrame = function(frameState, laye
   this.layerState_ = layerState;
   var viewState = frameState.viewState;
   var replayGroup = this.replayGroup_;
+  var size = frameState.size;
+  var pixelRatio = frameState.pixelRatio;
+  var gl = this.mapRenderer.getGL();
   if (replayGroup && !replayGroup.isEmpty()) {
+    gl.enable(gl.SCISSOR_TEST);
+    gl.scissor(0, 0, size[0] * pixelRatio, size[1] * pixelRatio);
     replayGroup.replay(context,
         viewState.center, viewState.resolution, viewState.rotation,
-        frameState.size, frameState.pixelRatio, layerState.opacity,
+        size, pixelRatio, layerState.opacity,
         layerState.managed ? frameState.skippedFeatureUids : {});
+    gl.disable(gl.SCISSOR_TEST);
   }
 
 };