1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
//! This example illustrates how to load and play an audio file, and control where the sounds seems to come from.
use bevy::{
    color::palettes::basic::{BLUE, LIME, RED},
    prelude::*,
};

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup)
        .add_systems(Update, update_positions)
        .add_systems(Update, update_listener)
        .run();
}

fn setup(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    // Space between the two ears
    let gap = 4.0;

    // sound emitter
    commands.spawn((
        PbrBundle {
            mesh: meshes.add(Sphere::new(0.2).mesh().uv(32, 18)),
            material: materials.add(Color::from(BLUE)),
            transform: Transform::from_xyz(0.0, 0.0, 0.0),
            ..default()
        },
        Emitter::default(),
        AudioBundle {
            source: asset_server.load("sounds/Windless Slopes.ogg"),
            settings: PlaybackSettings::LOOP.with_spatial(true),
        },
    ));

    let listener = SpatialListener::new(gap);
    commands
        .spawn((SpatialBundle::default(), listener.clone()))
        .with_children(|parent| {
            // left ear indicator
            parent.spawn(PbrBundle {
                mesh: meshes.add(Cuboid::new(0.2, 0.2, 0.2)),
                material: materials.add(Color::from(RED)),
                transform: Transform::from_translation(listener.left_ear_offset),
                ..default()
            });

            // right ear indicator
            parent.spawn(PbrBundle {
                mesh: meshes.add(Cuboid::new(0.2, 0.2, 0.2)),
                material: materials.add(Color::from(LIME)),
                transform: Transform::from_translation(listener.right_ear_offset),
                ..default()
            });
        });

    // light
    commands.spawn(DirectionalLightBundle {
        transform: Transform::from_xyz(4.0, 8.0, 4.0).looking_at(Vec3::ZERO, Vec3::Y),
        ..default()
    });

    // example instructions
    commands.spawn(
        TextBundle::from_section(
            "Up/Down/Left/Right: Move Listener\nSpace: Toggle Emitter Movement",
            TextStyle::default(),
        )
        .with_style(Style {
            position_type: PositionType::Absolute,
            bottom: Val::Px(12.0),
            left: Val::Px(12.0),
            ..default()
        }),
    );

    // camera
    commands.spawn(Camera3dBundle {
        transform: Transform::from_xyz(0.0, 5.0, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
        ..default()
    });
}

#[derive(Component, Default)]
struct Emitter {
    stopped: bool,
}

fn update_positions(
    time: Res<Time>,
    mut emitters: Query<(&mut Transform, &mut Emitter), With<Emitter>>,
    keyboard: Res<ButtonInput<KeyCode>>,
) {
    for (mut emitter_transform, mut emitter) in emitters.iter_mut() {
        if keyboard.just_pressed(KeyCode::Space) {
            emitter.stopped = !emitter.stopped;
        }

        if !emitter.stopped {
            emitter_transform.translation.x = time.elapsed_seconds().sin() * 3.0;
            emitter_transform.translation.z = time.elapsed_seconds().cos() * 3.0;
        }
    }
}

fn update_listener(
    keyboard: Res<ButtonInput<KeyCode>>,
    time: Res<Time>,
    mut listeners: Query<&mut Transform, With<SpatialListener>>,
) {
    let mut transform = listeners.single_mut();

    let speed = 2.;

    if keyboard.pressed(KeyCode::ArrowRight) {
        transform.translation.x += speed * time.delta_seconds();
    }
    if keyboard.pressed(KeyCode::ArrowLeft) {
        transform.translation.x -= speed * time.delta_seconds();
    }
    if keyboard.pressed(KeyCode::ArrowDown) {
        transform.translation.z += speed * time.delta_seconds();
    }
    if keyboard.pressed(KeyCode::ArrowUp) {
        transform.translation.z -= speed * time.delta_seconds();
    }
}