parse NO_VR=0

src/bin/vrtue.rs

@@ -15,10 +15,9 @@ use std::env;
 
 pub fn main() {
   env_logger::init().expect("env logger");
-  let mut vr = if env::var("NO_VR").is_ok() {
-    None
-  } else {
-    Some(vr::VR::new().expect("VR init"))
+  let mut vr = match env::var("NO_VR") {
+    Ok(ref no_vr) if no_vr != "0" => None,
+    _                             => Some(vr::VR::new().expect("VR init"))
   };
 
   let mut window: PistonWindow =