desktop: Don't render while minimized

On desktop, don't render while the window is minimized.

In the wgpu backend, don't panic if swap chain fails to grab a
texture. Instead recreate the swap chain and bail on the current
frame.

Fixes panic when minimizing with the wgpu vulkan backend (#2065).

desktop/src/main.rs

@@ -247,7 +247,7 @@ fn run_player(opt: Opt) -> Result<(), Box<dyn std::error::Error>> {
     let mut mouse_pos = PhysicalPosition::new(0.0, 0.0);
     let mut time = Instant::now();
     let mut next_frame_time = Instant::now();
-
+    let mut minimized = false;
     loop {
         // Poll UI events
         event_loop.run(move |event, _window_target, control_flow| {
@@ -273,10 +273,18 @@ fn run_player(opt: Opt) -> Result<(), Box<dyn std::error::Error>> {
                 }
 
                 // Render
-                winit::event::Event::RedrawRequested(_) => player.lock().unwrap().render(),
+                winit::event::Event::RedrawRequested(_) => {
+                    // Don't render when minimized to avoid potential swap chain errors in `wgpu`.
+                    if !minimized {
+                        player.lock().unwrap().render();
+                    }
+                }
 
                 winit::event::Event::WindowEvent { event, .. } => match event {
                     WindowEvent::Resized(size) => {
+                        // TODO: Change this when winit adds a `Window::minimzed` or `WindowEvent::Minimize`.
+                        minimized = size.width == 0 && size.height == 0;
+
                         let mut player_lock = player.lock().unwrap();
                         player_lock.set_viewport_dimensions(size.width, size.height);
                         player_lock

render/wgpu/src/lib.rs

@@ -909,7 +909,13 @@ impl<T: RenderTarget + 'static> RenderBackend for WgpuRenderBackend<T> {
             Ok(frame) => frame,
             Err(e) => {
                 log::warn!("Couldn't begin new render frame: {}", e);
-                panic!();
+                // Attemp to recreate the swap chain in this case.
+                self.target.resize(
+                    &self.descriptors.device,
+                    self.target.width(),
+                    self.target.height(),
+                );
+                return;
             }
         };