Sleep to not have 100% CPU usage

src/programs/viewer.rs

@@ -6,6 +6,7 @@ extern crate model_converter;
 
 use std::process::exit;
 use std::time::{Instant, Duration};
+use std::thread::sleep;
 
 use clap::{App, Arg};
 
@@ -133,6 +134,9 @@ fn main() {
     renderer.show();
 
     use model_converter::controls::Controls;
+
+    let mut before = Instant::now();
+
     while !closed {
 
         events_loop.poll_events(|ev| {
@@ -160,6 +164,12 @@ fn main() {
 
         controls.update(&mut camera, &renderer);
         renderer.render(&scene, &camera);
+        let elapsed = as_millis(Instant::now().duration_since(before));
 
+        if elapsed < 20 {
+            sleep(Duration::from_millis(20 - elapsed));
+        }
+
+        before = Instant::now();
     }
 }