Merge pull request #36 from AzureMarker/example/futures-basic

Add a basic futures example

.gitignore

@@ -1,3 +1,6 @@
 target
 Cargo.lock
 .cargo
+
+# IDE files
+.idea

ctru-rs/Cargo.toml

@@ -25,6 +25,7 @@ toml = "0.5"
 
 [dev-dependencies]
 ferris-says = "0.2.1"
+futures = "0.3"
 time = "0.3.7"
 
 [features]

ctru-rs/examples/futures-basic.rs

@@ -0,0 +1,73 @@
+//! This example runs a basic future executor from the `futures` library.
+//! Every 60 frames (about 1 second) it prints "Tick" to the console.
+//! The executor runs on a separate thread. Internally it yields when it has no more work to do,
+//! allowing other threads to run.
+//! The example also implements clean shutdown by using a oneshot channel to end the future, thus
+//! ending the executor and the thread it runs on.
+
+use ctru::console::Console;
+use ctru::services::hid::KeyPad;
+use ctru::services::{Apt, Hid};
+use ctru::Gfx;
+use futures::StreamExt;
+
+fn main() {
+    ctru::init();
+    let gfx = Gfx::default();
+    let hid = Hid::init().expect("Couldn't obtain HID controller");
+    let apt = Apt::init().expect("Couldn't obtain APT controller");
+    let _console = Console::init(gfx.top_screen.borrow_mut());
+
+    // Give ourselves up to 30% of the system core's time
+    apt.set_app_cpu_time_limit(30)
+        .expect("Failed to enable system core");
+
+    println!("Starting executor...");
+
+    let (exit_sender, mut exit_receiver) = futures::channel::oneshot::channel();
+    let (mut timer_sender, mut timer_receiver) = futures::channel::mpsc::channel(0);
+    let executor_thread = ctru::thread::Builder::new()
+        .affinity(1)
+        .spawn(move || {
+            let mut executor = futures::executor::LocalPool::new();
+
+            executor.run_until(async move {
+                loop {
+                    futures::select! {
+                        _ = exit_receiver => break,
+                        _ = timer_receiver.next() => {
+                            println!("Tick");
+                        }
+                    }
+                }
+            });
+        })
+        .expect("Failed to create executor thread");
+
+    println!("Executor started!");
+
+    let mut frame_count = 0;
+    while apt.main_loop() {
+        hid.scan_input();
+
+        if hid.keys_down().contains(KeyPad::KEY_START) {
+            println!("Shutting down...");
+            let _ = exit_sender.send(());
+            let _ = executor_thread.join();
+            break;
+        }
+
+        frame_count += 1;
+
+        if frame_count == 60 {
+            if let Err(e) = timer_sender.try_send(()) {
+                println!("Error sending timer message: {e}");
+            }
+            frame_count = 0;
+        }
+
+        gfx.flush_buffers();
+        gfx.swap_buffers();
+        gfx.wait_for_vblank();
+    }
+}