game states

src/bin/states.rs

@@ -0,0 +1,77 @@
+use bevy::prelude::*;
+
+#[derive(States, Clone, Copy, Eq, PartialEq, Debug, Hash)]
+enum AppState {
+    Splash,
+    Menu,
+    Game,
+}
+
+fn main() {
+    App::new()
+        .add_plugins(DefaultPlugins)
+        .insert_state(AppState::Splash)
+        .add_systems(Startup, setup)
+        // define transitions :
+        .add_systems(OnEnter(AppState::Splash), setup_splash)
+        .add_systems(OnEnter(AppState::Menu), setup_menu)
+        .add_systems(Update, splash_screen.run_if(in_state(AppState::Splash)))
+        .run();
+}
+
+#[derive(Component)]
+struct SplashScreenTimer(Timer);
+
+#[derive(Component)]
+struct GameFont(Handle<Font>);
+
+fn splash_screen(
+    mut commands: Commands,
+    time: ResMut<Time>,
+    mut timer: Single<&mut SplashScreenTimer>,
+    text: Single<Entity, With<Text2d>>,
+    mut next_state: ResMut<NextState<AppState>>,
+) {
+    if timer.0.tick(time.delta()).just_finished() {
+        commands.entity(text.into_inner()).despawn();
+        next_state.set(AppState::Menu);
+    }
+}
+
+fn setup_splash(mut commands: Commands, asset_server: Res<AssetServer>) {
+    let font = asset_server.load("fonts/monogram/ttf/monogram.ttf");
+    let text_font = TextFont {
+        font: font.clone(),
+        font_size: 50.0,
+        ..default()
+    };
+    let text_justification = JustifyText::Center;
+
+    commands.spawn((
+        Text2d::new("Splash Screen lol"),
+        text_font,
+        TextLayout::new_with_justify(text_justification),
+    ));
+
+    commands.spawn(SplashScreenTimer(Timer::from_seconds(2.0, TimerMode::Once)));
+}
+
+fn setup_menu(mut commands: Commands, asset_server: Res<AssetServer>) {
+    let font = asset_server.load("fonts/monogram/ttf/monogram.ttf");
+    let text_font = TextFont {
+        font: font.clone(),
+        font_size: 50.0,
+        ..default()
+    };
+    let text_justification = JustifyText::Center;
+
+    commands.spawn((
+        Text2d::new("Game Menu"),
+        text_font,
+        TextLayout::new_with_justify(text_justification),
+    ));
+}
+
+fn setup(mut commands: Commands) {
+    commands.spawn(Camera2d::default());
+}

src/bin/tetris.rs

@@ -1,3 +1,5 @@
+use bevy::prelude::*;
+
 fn main() {
-    todo!();
+    App::new().add_plugins(DefaultPlugins).run();
 }