feat(display): input routed via display server to focused app; input Subscribe; uses caps badged + Delegate

crates/apps/snake/src/main.rs

@@ -12,8 +12,8 @@ use libkos::syscall;
 use server_framework::Encode;
 use display_server::protocol::DisplayRequest;
 
-const INPUT_EP: CapSlot = CapSlot::const_new(0);
-const DISPLAY_EP: CapSlot = CapSlot::const_new(1);
+/// Input comes through the display server too, while this app has focus.
+const DISPLAY_EP: CapSlot = CapSlot::const_new(0);
 const TICK_DELAY: u64 = 5_000_000;
 const MAX_RENDER_CMDS: usize = 140;
 
@@ -37,6 +37,8 @@ fn flush() {
 
 #[unsafe(no_mangle)]
 extern "C" fn main() {
+    // Takes focus; the game polls every tick, so it never waits on the signal.
+    let _ = libkos::display::subscribe_input(DISPLAY_EP);
     let mut snake = Snake::new();
     let mut commands = [RenderCommand { x: 0, y: 0, w: 0, h: 0, color: 0 }; MAX_RENDER_CMDS];
 
@@ -65,7 +67,7 @@ extern "C" fn main() {
 fn handle_input(snake: &mut Snake) {
     // Drain all pending events, apply the latest direction
     loop {
-        let Ok([tag, kind, _, _]) = syscall::request(INPUT_EP, [0; 4]) else {
+        let Ok([tag, kind, _, _]) = syscall::request(DISPLAY_EP, [types::display::input::POLL, 0, 0, 0]) else {
             break;
         };
         if tag == 0 { break; } // NoEvent — queue drained