turning off antialiasing and device pixel ratio for better performance

js/overlay.js

diff --git a/js/overlay.js b/js/overlay.js
index 2337e60..97db6fb 100644
--- a/js/overlay.js
+++ b/js/overlay.js
@@ -70,9 +70,9 @@
   // Set up the THREE.js renderer.
   var renderer = this.renderer = new THREE.WebGLRenderer({
     alpha: true,
-    antialias: true
+    antialias: false
   });
-  renderer.setPixelRatio(window.devicePixelRatio);
+  renderer.setPixelRatio(1);
   renderer.setSize(width, height);
   style = renderer.domElement.style;
   style.pointerEvents = 'none';