Make project runnable on stable toolchain

Tested on rustc 1.58.1 (db9d1b20b 2022-01-20)

src/main.rs

@@ -168,12 +168,14 @@ fn main() {
             prevous_frame_time = now;
 
             // Handle resize events
-            if let Ok(mut new_size) = window_size.lock() && new_size.2 {
-                context.resize(glutin::dpi::PhysicalSize::new(new_size.0, new_size.1));
-                window_aspect_ratio = new_size.0 as f32 / new_size.1 as f32;
-                (*new_size).2 = false;
-                println!("Resized");
-                unsafe { gl::Viewport(0, 0, new_size.0 as i32, new_size.1 as i32); }
+            if let Ok(mut new_size) = window_size.lock() {
+                if new_size.2 {
+                    context.resize(glutin::dpi::PhysicalSize::new(new_size.0, new_size.1));
+                    window_aspect_ratio = new_size.0 as f32 / new_size.1 as f32;
+                    (*new_size).2 = false;
+                    println!("Resized");
+                    unsafe { gl::Viewport(0, 0, new_size.0 as i32, new_size.1 as i32); }
+                }
             }
 
             // Handle keyboard input