bell_catcher/
bell_catcher.rs

1//! Bell Catcher: bells fall somewhere in front of you. Listen where one rings, step under it
2//! and catch it before it lands. The faster you are, the faster they fall.
3//!
4//! * Left / Right: step one lane
5//! * S: score and lives
6//! * Escape: back to the menu
7//!
8//! The menu lets players pick a speech voice and rate; both are saved with the best score.
9//! All sounds are generated with the synth, so no files are needed.
10//! Run with `cargo run --example bell_catcher` and use headphones.
11
12use audio_code::prelude::*;
13
14/// Lanes go from -LANES to LANES, 0 is the middle.
15const LANES: i32 = 3;
16const LANE_WIDTH: f32 = 1.5;
17const LIVES: u32 = 3;
18/// Seconds a bell needs to land, at the start and at most speed.
19const FIRST_FALL: f32 = 3.0;
20const FASTEST_FALL: f32 = 1.0;
21
22fn main() -> audio_code::Result<()> {
23    Engine::new("Bell Catcher").run_with(|ctx| {
24        ctx.audio.register("bell", Synth::sine(1568.0).with(Synth::sine(3136.0).volume(0.3)).length(0.35).decay(9.0).volume(0.6));
25        ctx.audio.register("step", Synth::noise().length(0.05).decay(80.0).volume(0.5));
26        ctx.audio.register("edge", Synth::sine(110.0).length(0.12).decay(30.0).volume(0.8));
27        ctx.audio.register(
28            "catch",
29            Synth::sine(784.0).length(0.08).then(Synth::sine(1047.0).length(0.08)).then(Synth::sine(1568.0).length(0.2).decay(12.0)).volume(0.4),
30        );
31        ctx.audio.register("miss", Synth::saw(220.0).sweep_to(80.0).length(0.5).decay(5.0).volume(0.35));
32
33        // Restore the speech settings from the last session.
34        if let Some(voice) = ctx.storage.get::<String>("voice") {
35            ctx.speech.set_voice(voice);
36        }
37        let rate: f32 = ctx.storage.get_or("rate", 50.0);
38        if rate != 50.0 {
39            ctx.speech.set_rate(rate / 100.0);
40        }
41        Title
42    })
43}
44
45// ------------------------------------------------------------------------- menu
46
47struct Title;
48
49fn title_menu(ctx: &Context) -> Menu {
50    let voice = ctx.speech.voice().map_or("default".to_string(), |v| v.name.clone());
51    let best: u32 = ctx.storage.get_or("best", 0);
52    Menu::new("title", "Bell Catcher")
53        .button("play", "Play")
54        .button("voice", format!("Voice: {voice}"))
55        .slider("rate", "Speech rate", ctx.storage.get_or("rate", 50.0), 0.0, 100.0, 5.0)
56        .button("help", "How to play")
57        .label(format!("Best score: {best}"))
58        .button("quit", "Quit")
59        .closable(false)
60        .wrap(true)
61}
62
63/// One button per voice, with the current one focused. `None` if the output has no voices.
64fn voice_menu(ctx: &Context) -> Option<Menu> {
65    let voices = ctx.speech.voices();
66    if voices.is_empty() {
67        return None;
68    }
69    let mut menu = Menu::new("voices", "Choose a voice").button("default", "Default voice");
70    for (i, voice) in voices.iter().enumerate() {
71        menu = menu.button(format!("voice{i}"), voice.to_string());
72    }
73    if let Some(i) = ctx.speech.voice().and_then(|current| voices.iter().position(|v| v == current)) {
74        menu = menu.focus(&format!("voice{i}"));
75    }
76    Some(menu.button("back", "Back"))
77}
78
79/// Reopens the title menu so its labels show the new values, focused on `item`.
80fn refresh_title(ctx: &mut Context, item: &str) {
81    ctx.ui.close_id("title");
82    let menu = title_menu(ctx).focus(item);
83    ctx.ui.open(menu);
84}
85
86impl Scene for Title {
87    fn start(&mut self, ctx: &mut Context) {
88        let menu = title_menu(ctx);
89        ctx.ui.open(menu);
90    }
91
92    fn on_ui(&mut self, event: &UiEvent, ctx: &mut Context) {
93        match event {
94            UiEvent::Activated { menu, item } if menu == "title" => match item.as_str() {
95                "play" => {
96                    ctx.ui.close_all();
97                    ctx.switch_scene(Game::default());
98                }
99                "voice" => match voice_menu(ctx) {
100                    Some(menu) => ctx.ui.open(menu),
101                    None => ctx.ui.message(
102                        "no voices",
103                        "Your screen reader speaks with its own voice. Change it in the screen reader's settings.",
104                    ),
105                },
106                "help" => ctx.ui.message(
107                    "help",
108                    "Bells fall in one of seven lanes in front of you. Listen where a bell rings, \
109                     step under it with left and right, and catch it before it lands. \
110                     The bell rings faster and higher the closer it gets. You have three lives. \
111                     Press S for your score, Escape for the menu.",
112                ),
113                "quit" => ctx.quit(),
114                _ => {}
115            },
116            UiEvent::Activated { menu, item } if menu == "voices" => {
117                if item == "back" {
118                    ctx.ui.close();
119                    return;
120                }
121                if item == "default" {
122                    ctx.speech.reset_voice();
123                    ctx.storage.remove("voice");
124                } else if let Some(voice) =
125                    item.strip_prefix("voice").and_then(|i| i.parse::<usize>().ok()).and_then(|i| ctx.speech.voices().get(i).cloned())
126                    && ctx.speech.set_voice(&voice.id)
127                {
128                    ctx.storage.set("voice", &voice.id);
129                }
130                ctx.ui.close();
131                refresh_title(ctx, "voice");
132                let name = ctx.speech.voice().map_or("Default voice".to_string(), |v| v.name.clone());
133                ctx.speech.speak_queued(format!("{name}. This is how I sound now."));
134            }
135            UiEvent::Changed { menu, item, value } if menu == "title" && item == "rate" => {
136                ctx.speech.set_rate(value.as_f32() / 100.0);
137                ctx.storage.set("rate", value.as_f32());
138            }
139            _ => {}
140        }
141    }
142
143    fn update(&mut self, _ctx: &mut Context) {}
144}
145
146// ------------------------------------------------------------------------- game
147
148struct Game {
149    lane: i32,
150    bell_lane: i32,
151    /// Seconds a bell needs to land; shrinks with every catch.
152    fall: f32,
153    /// Seconds until the current bell lands. Negative while waiting for the next bell.
154    left: f32,
155    next_ring: f32,
156    score: u32,
157    lives: u32,
158    over: bool,
159}
160
161impl Default for Game {
162    fn default() -> Self {
163        Self { lane: 0, bell_lane: 0, fall: FIRST_FALL, left: 0.0, next_ring: 0.0, score: 0, lives: LIVES, over: false }
164    }
165}
166
167impl Game {
168    fn drop_bell(&mut self) {
169        self.bell_lane = random::int(-LANES as i64, LANES as i64) as i32;
170        self.left = self.fall;
171        self.next_ring = 0.0;
172    }
173
174    /// Where the bell is, seen from the player: lanes to the side, a little in front.
175    fn bell_position(&self) -> Vec3 {
176        vec3((self.bell_lane - self.lane) as f32 * LANE_WIDTH, 2.0, 0.0)
177    }
178
179    fn ring(&mut self, ctx: &mut Context) {
180        // 0.0 when the bell starts falling, 1.0 when it lands.
181        let progress = 1.0 - self.left / self.fall;
182        let position = self.bell_position();
183        ctx.audio.sound("bell").at(position).pitch(1.0 + progress * 0.6).play();
184        self.next_ring = 0.12 + 0.45 * (1.0 - progress);
185    }
186
187    fn land(&mut self, ctx: &mut Context) {
188        if self.lane == self.bell_lane {
189            self.score += 1;
190            self.fall = (self.fall * 0.93).max(FASTEST_FALL);
191            ctx.play("catch");
192            if self.score.is_multiple_of(5) {
193                ctx.speak(format!("{} bells!", self.score));
194            }
195        } else {
196            self.lives -= 1;
197            ctx.play("miss");
198            match self.lives {
199                0 => return self.game_over(ctx),
200                1 => ctx.speak("Missed! Last life."),
201                n => ctx.speak(format!("Missed! {n} lives left.")),
202            }
203        }
204        // A short break before the next bell.
205        self.left = -0.8;
206    }
207
208    fn game_over(&mut self, ctx: &mut Context) {
209        self.over = true;
210        let best: u32 = ctx.storage.get_or("best", 0);
211        let text = if self.score > best {
212            ctx.storage.set("best", self.score);
213            format!("Game over. {} bells, a new best score!", self.score)
214        } else {
215            format!("Game over. {} bells. Your best is {best}.", self.score)
216        };
217        ctx.ui.message("over", text);
218    }
219}
220
221impl Scene for Game {
222    fn start(&mut self, ctx: &mut Context) {
223        ctx.speak("Catch the bells! Left and right to move.");
224        // Give the player a moment to listen to the first bell.
225        self.left = -1.5;
226    }
227
228    fn update(&mut self, ctx: &mut Context) {
229        if self.over {
230            if ctx.ui.closed("over") {
231                ctx.switch_scene(Title);
232            }
233            return;
234        }
235        if ctx.pressed(Key::Escape) {
236            ctx.switch_scene(Title);
237            return;
238        }
239        if ctx.pressed(Key::S) {
240            ctx.speak(format!("{} bells, {} lives", self.score, self.lives));
241        }
242        for (key, step) in [(Key::Left, -1), (Key::Right, 1)] {
243            if ctx.input.repeating(key, 0.3, 0.15) {
244                let lane = (self.lane + step).clamp(-LANES, LANES);
245                if lane == self.lane {
246                    ctx.play("edge");
247                } else {
248                    self.lane = lane;
249                    ctx.audio.sound("step").at(vec3(step as f32 * 0.5, 0.0, 0.0)).random_pitch(0.9, 1.1).play();
250                }
251            }
252        }
253
254        let dt = ctx.time.delta();
255        if self.left < 0.0 {
256            self.left += dt;
257            if self.left >= 0.0 {
258                self.drop_bell();
259            }
260            return;
261        }
262        self.left -= dt;
263        self.next_ring -= dt;
264        if self.left <= 0.0 {
265            self.land(ctx);
266        } else if self.next_ring <= 0.0 {
267            self.ring(ctx);
268        }
269    }
270}
271
bell_catcher/bell_catcher.rs

bell_catcher/
bell_catcher.rs
