platformer/
platformer.rs

1//! A tiny side scroller using gravity: run with Left/Right, jump with Space, collect coins.
2//! Uses x for left/right and z for up/down. A lift carries you to the last coin, and a
3//! crate can be pushed around. All sounds are generated with the synth.
4//!
5//! Run with `cargo run --example platformer`.
6
7use audio_code::prelude::*;
8
9const COINS: usize = 4;
10
11struct Platformer {
12    player: BodyId,
13    lift: BodyId,
14    run_sound: Sound,
15    score: usize,
16}
17
18impl Platformer {
19    fn new(ctx: &mut Context) -> Self {
20        let audio = &mut ctx.audio;
21        audio.register("jump", Synth::square(300.0).sweep_to(700.0).length(0.15).decay(10.0).volume(0.2));
22        audio.register("land", Synth::noise().length(0.1).decay(40.0).with(Synth::sine(90.0).length(0.1).decay(30.0)));
23        audio.register("coin", Synth::triangle(988.0).length(0.08).then(Synth::triangle(1319.0).length(0.17).decay(15.0)));
24        audio.register("run", Synth::noise().length(0.06).decay(60.0).volume(0.3).then(Synth::silence(0.09)));
25        audio.register("lift", Synth::saw(55.0).length(1.0).volume(0.1));
26        audio.register("push", Synth::noise().length(0.3).volume(0.15));
27
28        let physics = &mut ctx.physics;
29        physics.add(Body::fixed(vec3(0.0, 0.0, -0.5)).with_box(200.0, 4.0, 1.0).with_tag("ground"));
30        for (x, z) in [(8.0, 2.0), (14.0, 4.0), (20.0, 2.5)] {
31            physics.add(Body::fixed(vec3(x, 0.0, z)).with_box(4.0, 4.0, 0.5).with_tag("platform"));
32        }
33        // A lift going up and down at x = 40, and a heavy crate at x = 30.
34        let lift = physics.add(Body::kinematic(vec3(40.0, 0.0, 0.0)).with_box(3.0, 4.0, 0.5).with_tag("lift"));
35        physics.add(Body::dynamic(vec3(30.0, 0.0, 0.5)).with_box(1.0, 1.0, 1.0).with_mass(5.0).with_tag("crate"));
36        // Facing north, so x maps to left and right in the ears.
37        let player = physics
38            .add(Body::dynamic(vec3(0.0, 0.0, 1.0)).with_box(0.8, 0.8, 1.6).with_max_speed(25.0).with_tag("player"));
39
40        ctx.follow(player);
41        ctx.loop_on(lift, "lift");
42        // Coins are sensors with a looping sound, so you can hear where they are.
43        for (x, z) in [(5.0, 1.0), (14.0, 5.5), (25.0, 1.0), (40.0, 8.0)] {
44            let coin = ctx.physics.add(Body::sensor(vec3(x, 0.0, z)).with_sphere(0.6).with_tag("coin"));
45            ctx.loop_on(coin, "coin").set_volume(0.3);
46        }
47
48        let run_sound = ctx.audio.sound("run").looped().volume(0.0).play();
49        Self { player, lift, run_sound, score: 0 }
50    }
51}
52
53impl Scene for Platformer {
54    fn start(&mut self, ctx: &mut Context) {
55        ctx.speak("Collect the coins. Left and right to run, space to jump, S for score, escape to quit.");
56    }
57
58    fn update(&mut self, ctx: &mut Context) {
59        if ctx.pressed(Key::Escape) {
60            ctx.quit();
61        }
62
63        // The lift goes up for 4 seconds and down for 4 seconds.
64        let lift_up = (ctx.time.elapsed() % 8.0) < 4.0;
65        ctx.physics.set_velocity(self.lift, vec3(0.0, 0.0, if lift_up { 2.0 } else { -2.0 }));
66
67        let run = ctx.input.axis(Key::Left, Key::Right);
68        let mut velocity = ctx.physics.velocity(self.player);
69        velocity.x = run * 6.0;
70        ctx.physics.set_velocity(self.player, velocity);
71        if ctx.pressed(Key::Space) && ctx.physics.jump(self.player, 2.5) {
72            ctx.play("jump");
73        }
74        let running = ctx.physics.on_ground(self.player) && run != 0.0;
75        self.run_sound.set_volume(if running { 0.6 } else { 0.0 });
76
77        if let Some(speed) = ctx.physics.landed(self.player) {
78            ctx.audio.sound("land").volume((speed / 12.0).clamp(0.2, 1.0)).play();
79            if speed > 15.0 {
80                ctx.speak("Ouch!");
81            }
82        }
83        if let Some((other, _)) = ctx.physics.collided(self.player)
84            && ctx.physics.tag(other) == "crate"
85        {
86            ctx.play_on(other, "push");
87        }
88        if let Some(coin) = ctx.physics.entered_tag(self.player, "coin") {
89            ctx.physics.remove(coin); // its looping sound stops by itself
90            self.score += 1;
91            ctx.audio.sound("coin").pitch(1.5).play();
92            ctx.speak(format!("{} of {COINS} coins", self.score));
93            if self.score == COINS {
94                ctx.ui.message("won", "You collected every coin! Press enter to quit.");
95            }
96        }
97        if ctx.ui.closed("won") {
98            ctx.quit();
99        }
100
101        if ctx.pressed(Key::S) {
102            let x = ctx.physics.position(self.player).x;
103            ctx.speak(format!("Score {}, position {x:.0}", self.score));
104        }
105    }
106}
107
108fn main() -> audio_code::Result<()> {
109    Engine::new("Platformer").gravity(EARTH_GRAVITY * 2.0).echo_speech(true).run_with(Platformer::new)
110}
platformer/platformer.rs

platformer/
platformer.rs
