1 files changed, 7 insertions, 3 deletions

diff --git a/js/lib/drawing/world.js b/js/lib/drawing/world.js
index 44c9e37d..df24f556 100755
--- a/js/lib/drawing/world.js
+++ b/js/lib/drawing/world.js
@@ -17,7 +17,7 @@ var worldCounter = 0;
 // Class GLWorld
 //      Manages display in a canvas
 ///////////////////////////////////////////////////////////////////////
-var World = function GLWorld( canvas, use3D ) {
+var World = function GLWorld( canvas, use3D, preserveDrawingBuffer ) {
     ///////////////////////////////////////////////////////////////////////
     // Instance variables
     ///////////////////////////////////////////////////////////////////////
@@ -30,7 +30,11 @@ var World = function GLWorld( canvas, use3D ) {
 
     this._canvas = canvas;
         if (this._useWebGL) {
-                this._glContext = canvas.getContext("experimental-webgl");
+        if(preserveDrawingBuffer) {
+            this._glContext = canvas.getContext("experimental-webgl", {preserveDrawingBuffer: true});
+        } else {
+                    this._glContext = canvas.getContext("experimental-webgl");
+        }
     } else {
                 this._2DContext = canvas.getContext( "2d" );
     }
@@ -680,7 +684,7 @@ World.prototype.render = function() {
                 var root = this.getGeomRoot();
                 this.hRender( root );
         } else {
-                g_Engine.setContext( this._canvas.rdgeId );
+                g_Engine.setContext( this._canvas.rdgeid );
                 //this.draw();
                 this.restartRenderLoop();
         }