egui: add frame timestep slider

locales/en-US/main.ftl

@@ -36,4 +36,6 @@ show-origin-destination = Show Origin–Destination
 
 show-layer-manager = Show Layer Manager
 
+frame-timestep = Frame Timestep
+
 specctra-session-file = Specctra session file

src/bin/topola-egui/app.rs

@@ -124,15 +124,19 @@ impl App {
         }
     }
 
-    fn update_state(&mut self, dt: f32) {
+    fn advance_state_by_dt(&mut self, dt: f32) {
         self.update_counter += dt;
 
-        if self.update_counter <= 0.1 {
+        while self.update_counter >= self.top.frame_timestep {
-            return;
+            self.update_counter -= self.top.frame_timestep;
+
+            if !self.update_state() {
+                return;
+            }
         }
+    }
 
-        self.update_counter = 0.0;
+    fn update_state(&mut self) -> bool {
-
         let mut content_file_receiver = FileReceiver::new(&self.content_channel.1);
 
         if let Ok(bufread) = content_file_receiver.try_recv() {
@@ -155,12 +159,15 @@ impl App {
             }
 
             if let Some(ref mut execute) = self.maybe_execute {
-                let status = match execute.step(invoker) {
+                match execute.step(invoker) {
-                    Ok(status) => status,
+                    Ok(InvokerStatus::Running) => return true,
-                    Err(err) => return,
+                    Ok(InvokerStatus::Finished(..)) => return false,
-                };
+                    Err(err) => return false,
+                }
             }
         }
+
+        false
     }
 }
 
@@ -184,7 +191,7 @@ impl eframe::App for App {
             &self.maybe_design,
         );
 
-        self.update_state(ctx.input(|i| i.stable_dt));
+        self.advance_state_by_dt(ctx.input(|i| i.stable_dt));
 
         self.bottom
             .update(ctx, &self.translator, &self.viewport, &self.maybe_execute);

src/bin/topola-egui/top.rs

@@ -31,6 +31,7 @@ pub struct Top {
     pub show_bboxes: bool,
     pub show_origin_destination: bool,
     pub show_layer_manager: bool,
+    pub frame_timestep: f32,
 }
 
 impl Top {
@@ -49,6 +50,7 @@ impl Top {
             show_bboxes: false,
             show_origin_destination: false,
             show_layer_manager: true,
+            frame_timestep: 0.1,
         }
     }
 
@@ -173,6 +175,14 @@ impl Top {
                         ui.separator();
 
                         ui.checkbox(&mut self.show_layer_manager, tr.text("show-layer-manager"));
+
+                        ui.separator();
+
+                        ui.label(tr.text("frame-timestep"));
+                        ui.add(egui::widgets::Slider::new(
+                            &mut self.frame_timestep,
+                            0.0..=3.0,
+                        ));
                     });
 
                     ui.menu_button(tr.text("menu-place"), |ui| {