* Fix example hello_world_par

* Added warning for glow eframe when creating `Context::create_viewport_sync` in other thread, or cannot be rendered!
* Fix clippy warning

crates/eframe/src/native/run.rs

@@ -1034,6 +1034,11 @@ mod glow_integration {
                                         );
                                         let glutin = &mut *glutin.write();
 
+                                        let screen_size_in_pixels: [u32; 2] =
+                                            win.inner_size().into();
+
+                                        let clipped_primitives = egui_ctx.tessellate(output.shapes);
+
                                         glutin.current_gl_context = Some(
                                             glutin
                                                 .current_gl_context
@@ -1045,8 +1050,14 @@ mod glow_integration {
                                                 .unwrap(),
                                         );
 
-                                        let screen_size_in_pixels: [u32; 2] =
-                                            win.inner_size().into();
+                                        if !window
+                                            .gl_surface
+                                            .as_ref()
+                                            .unwrap()
+                                            .is_current(glutin.current_gl_context.as_ref().unwrap())
+                                        {
+                                            log::error!("egui::create_viewport_sync with title: `{}` is not created in main thread, try to use wgpu!", window.builder.title);
+                                        }
 
                                         egui_glow::painter::clear(
                                             &_gl,
@@ -1054,8 +1065,6 @@ mod glow_integration {
                                             [0.0, 0.0, 0.0, 0.0],
                                         );
 
-                                        let clipped_primitives = egui_ctx.tessellate(output.shapes);
-
                                         _painter.write().paint_and_update_textures(
                                             screen_size_in_pixels,
                                             egui_ctx.pixels_per_point(),

crates/egui/src/context.rs

@@ -271,8 +271,7 @@ impl ContextImpl {
                 .memory
                 .new_pixels_per_viewport
                 .get(&viewport_id)
-                .map(|pixels| *pixels != new_pixels_per_point)
-                .unwrap_or(true)
+                .map_or(true, |pixels| *pixels != new_pixels_per_point)
             {
                 new_raw_input.pixels_per_point = Some(new_pixels_per_point);
                 self.memory

examples/hello_world_par/Cargo.toml

@@ -12,7 +12,7 @@ publish = false
 eframe = { path = "../../crates/eframe", default-features = false, features = [
     # accesskit struggles with threading
     "default_fonts",
-    "glow",
-    # "wgpu",
+    "wgpu",
+    "x11"
 ] }
 env_logger = "0.10"

examples/hello_world_par/src/main.rs

@@ -136,9 +136,6 @@ impl eframe::App for MyApp {
 
         for (_handle, show_tx) in &self.threads {
             let _ = show_tx.send(ctx.clone());
-        }
-
-        for _ in 0..self.threads.len() {
             let _ = self.on_done_rc.recv();
         }
     }