emulator: start supporting Android, this is WIP

Needs storage permissions, probably extra tweaks

emulator/src/main.rs

@@ -22,7 +22,18 @@ use dsa_rs::emulator::{
     },
 };
 
-fn main() -> Result<(), Box<dyn std::error::Error>> {
+#[cfg(target_os = "android")]
+use winit::platform::android::activity::AndroidApp;
+
+#[cfg(target_os = "android")]
+#[no_mangle]
+fn android_main(app: AndroidApp) {
+    main(app);
+}
+
+fn main(
+    #[cfg(target_os = "android")] app: AndroidApp,
+) -> Result<(), Box<dyn std::error::Error>> {
     // Initialize channels and read in configuration.
     let (cmd_sender, cmd_receiver) = std::sync::mpsc::channel();
     let (state_sender, state_reciever) = std::sync::mpsc::channel();
@@ -39,8 +50,13 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     let ui = setup_ui(cmd_sender, state_reciever);
 
     // Run UI.
+    #[allow(unused_variables)]
     let options = eframe::NativeOptions {
         viewport: egui::ViewportBuilder::default().with_inner_size([800.0, 600.0]),
+        event_loop_builder: Some(Box::new(move |builder| {
+            #[cfg(target_os = "android")]
+            builder.with_android_app(app);
+        })),
         ..Default::default()
     };