Always use the latest async callback when rendering a viewport

emilk · Nov 7, 2023 · 7bc5698 · 7bc5698
1 parent 6643713
commit 7bc5698
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Showing 3 changed files with 30 additions and 46 deletions.
diff --git a/crates/eframe/src/native/run.rs b/crates/eframe/src/native/run.rs
@@ -1276,9 +1276,9 @@ mod glow_integration {
                         if recreate {
                             viewport.window = None;
                             viewport.gl_surface = None;
-                            viewport.viewport_ui_cb = viewport_ui_cb.clone();
                             viewport.id_pair.parent = *id;
                         }
+                        viewport.viewport_ui_cb = viewport_ui_cb.clone(); // always update the latest callback
                         if let Some(w) = viewport.window.clone() {
                             process_viewport_commands(commands, *id, None, &w.borrow());
                         }

diff --git a/crates/egui/src/context.rs b/crates/egui/src/context.rs
@@ -1548,7 +1548,7 @@ impl Context {
         let mut viewports = Vec::new();
         self.write(|ctx| {
             ctx.viewports.retain(|_, viewport| {
-                let retain = viewport.used;
+                let was_used = viewport.used;
 
                 if viewport_id == viewport.id_pair.parent {
                     viewport.used = false;
@@ -1559,7 +1559,7 @@ impl Context {
                     id_pair: viewport.id_pair,
                     viewport_ui_cb: viewport.viewport_ui_cb.clone(),
                 });
-                (retain || viewport_id != viewport.id_pair.parent)
+                (was_used || viewport_id != viewport.id_pair.parent)
                     && available_viewports.contains(&viewport.id_pair.parent)
             });
         });

diff --git a/examples/test_viewports/src/main.rs b/examples/test_viewports/src/main.rs
@@ -57,17 +57,38 @@ impl ViewportState {
         }))
     }
 
-    pub fn show(slf: Arc<RwLock<ViewportState>>, ctx: &egui::Context) {
-        if !slf.read().visible {
+    pub fn show(vp_state: Arc<RwLock<ViewportState>>, ctx: &egui::Context) {
+        if !vp_state.read().visible {
             return;
         }
-        let id = slf.read().id;
-        let sync = slf.read().sync;
+        let vp_id = vp_state.read().id;
+        let sync = vp_state.read().sync;
+        let title = vp_state.read().title.clone();
+
+        let vp_builder = ViewportBuilder::new(vp_id)
+            .with_title(&title)
+            .with_inner_size(Some(egui::vec2(450.0, 400.0)));
 
         if sync {
-            show_sync_viewport(ctx, id, &mut slf.write());
+            let mut vp_state = vp_state.write();
+            ctx.create_viewport_sync(vp_builder, move |ctx| {
+                show_as_popup(ctx, &title, vp_id.into(), |ui: &mut egui::Ui| {
+                    generic_child_ui(ui, &mut vp_state);
+                });
+            });
         } else {
-            show_async_viewport(ctx, id, slf);
+            let count = Arc::new(RwLock::new(0));
+            ctx.create_viewport_async(vp_builder, move |ctx| {
+                let mut vp_state = vp_state.write();
+                let count = count.clone();
+                show_as_popup(ctx, &title, vp_id.into(), move |ui: &mut egui::Ui| {
+                    let current_count = *count.read();
+                    ui.label(format!("Callback has been reused {current_count} times"));
+                    *count.write() += 1;
+
+                    generic_child_ui(ui, &mut vp_state);
+                });
+            });
         }
     }
 }
@@ -114,43 +135,6 @@ impl eframe::App for App {
     }
 }
 
-fn show_async_viewport(
-    ctx: &egui::Context,
-    vp_id: ViewportId,
-    vp_state: Arc<RwLock<ViewportState>>,
-) {
-    let id = Id::from(vp_id);
-    let title = vp_state.read().title.clone();
-
-    ctx.create_viewport_async(
-        ViewportBuilder::new(vp_id)
-            .with_title(&title)
-            .with_inner_size(Some(egui::vec2(450.0, 400.0))),
-        move |ctx| {
-            let mut vp_state = vp_state.write();
-            show_as_popup(ctx, &title, id, move |ui: &mut egui::Ui| {
-                generic_child_ui(ui, &mut vp_state);
-            });
-        },
-    );
-}
-
-fn show_sync_viewport(ctx: &egui::Context, vp_id: ViewportId, vp_state: &mut ViewportState) {
-    let id = Id::from(vp_id);
-    let title = vp_state.title.clone();
-
-    ctx.create_viewport_sync(
-        ViewportBuilder::new(vp_id)
-            .with_title(&title)
-            .with_inner_size(Some(egui::vec2(450.0, 400.0))),
-        move |ctx| {
-            show_as_popup(ctx, &title, id, |ui: &mut egui::Ui| {
-                generic_child_ui(ui, vp_state);
-            });
-        },
-    );
-}
-
 /// This will make the content as a popup if cannot has his own native window
 fn show_as_popup(ctx: &egui::Context, title: &str, id: Id, content: impl FnOnce(&mut egui::Ui)) {
     if ctx.viewport_id() == ctx.parent_viewport_id() {