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
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
//! Illustrates bloom post-processing using HDR and emissive materials.

use bevy::{
    color::palettes::basic::GRAY,
    core_pipeline::{
        bloom::{BloomCompositeMode, BloomSettings},
        tonemapping::Tonemapping,
    },
    prelude::*,
};
use std::{
    collections::hash_map::DefaultHasher,
    hash::{Hash, Hasher},
};

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_systems(Startup, setup_scene)
        .add_systems(Update, (update_bloom_settings, bounce_spheres))
        .run();
}

fn setup_scene(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    commands.spawn((
        Camera3dBundle {
            camera: Camera {
                hdr: true, // 1. HDR is required for bloom
                ..default()
            },
            tonemapping: Tonemapping::TonyMcMapface, // 2. Using a tonemapper that desaturates to white is recommended
            transform: Transform::from_xyz(-2.0, 2.5, 5.0).looking_at(Vec3::ZERO, Vec3::Y),
            ..default()
        },
        // 3. Enable bloom for the camera
        BloomSettings::NATURAL,
    ));

    let material_emissive1 = materials.add(StandardMaterial {
        emissive: LinearRgba::rgb(13.99, 5.32, 2.0), // 4. Put something bright in a dark environment to see the effect
        ..default()
    });
    let material_emissive2 = materials.add(StandardMaterial {
        emissive: LinearRgba::rgb(2.0, 13.99, 5.32),
        ..default()
    });
    let material_emissive3 = materials.add(StandardMaterial {
        emissive: LinearRgba::rgb(5.32, 2.0, 13.99),
        ..default()
    });
    let material_non_emissive = materials.add(StandardMaterial {
        base_color: GRAY.into(),
        ..default()
    });

    let mesh = meshes.add(Sphere::new(0.5).mesh().ico(5).unwrap());

    for x in -5..5 {
        for z in -5..5 {
            // This generates a pseudo-random integer between `[0, 6)`, but deterministically so
            // the same spheres are always the same colors.
            let mut hasher = DefaultHasher::new();
            (x, z).hash(&mut hasher);
            let rand = (hasher.finish() - 2) % 6;

            let material = match rand {
                0 => material_emissive1.clone(),
                1 => material_emissive2.clone(),
                2 => material_emissive3.clone(),
                3..=5 => material_non_emissive.clone(),
                _ => unreachable!(),
            };

            commands.spawn((
                PbrBundle {
                    mesh: mesh.clone(),
                    material,
                    transform: Transform::from_xyz(x as f32 * 2.0, 0.0, z as f32 * 2.0),
                    ..default()
                },
                Bouncing,
            ));
        }
    }

    // example instructions
    commands.spawn(
        TextBundle::from_section("", TextStyle::default()).with_style(Style {
            position_type: PositionType::Absolute,
            bottom: Val::Px(12.0),
            left: Val::Px(12.0),
            ..default()
        }),
    );
}

// ------------------------------------------------------------------------------------------------

fn update_bloom_settings(
    mut camera: Query<(Entity, Option<&mut BloomSettings>), With<Camera>>,
    mut text: Query<&mut Text>,
    mut commands: Commands,
    keycode: Res<ButtonInput<KeyCode>>,
    time: Res<Time>,
) {
    let bloom_settings = camera.single_mut();
    let mut text = text.single_mut();
    let text = &mut text.sections[0].value;

    match bloom_settings {
        (entity, Some(mut bloom_settings)) => {
            *text = "BloomSettings (Toggle: Space)\n".to_string();
            text.push_str(&format!("(Q/A) Intensity: {}\n", bloom_settings.intensity));
            text.push_str(&format!(
                "(W/S) Low-frequency boost: {}\n",
                bloom_settings.low_frequency_boost
            ));
            text.push_str(&format!(
                "(E/D) Low-frequency boost curvature: {}\n",
                bloom_settings.low_frequency_boost_curvature
            ));
            text.push_str(&format!(
                "(R/F) High-pass frequency: {}\n",
                bloom_settings.high_pass_frequency
            ));
            text.push_str(&format!(
                "(T/G) Mode: {}\n",
                match bloom_settings.composite_mode {
                    BloomCompositeMode::EnergyConserving => "Energy-conserving",
                    BloomCompositeMode::Additive => "Additive",
                }
            ));
            text.push_str(&format!(
                "(Y/H) Threshold: {}\n",
                bloom_settings.prefilter_settings.threshold
            ));
            text.push_str(&format!(
                "(U/J) Threshold softness: {}\n",
                bloom_settings.prefilter_settings.threshold_softness
            ));

            if keycode.just_pressed(KeyCode::Space) {
                commands.entity(entity).remove::<BloomSettings>();
            }

            let dt = time.delta_seconds();

            if keycode.pressed(KeyCode::KeyA) {
                bloom_settings.intensity -= dt / 10.0;
            }
            if keycode.pressed(KeyCode::KeyQ) {
                bloom_settings.intensity += dt / 10.0;
            }
            bloom_settings.intensity = bloom_settings.intensity.clamp(0.0, 1.0);

            if keycode.pressed(KeyCode::KeyS) {
                bloom_settings.low_frequency_boost -= dt / 10.0;
            }
            if keycode.pressed(KeyCode::KeyW) {
                bloom_settings.low_frequency_boost += dt / 10.0;
            }
            bloom_settings.low_frequency_boost = bloom_settings.low_frequency_boost.clamp(0.0, 1.0);

            if keycode.pressed(KeyCode::KeyD) {
                bloom_settings.low_frequency_boost_curvature -= dt / 10.0;
            }
            if keycode.pressed(KeyCode::KeyE) {
                bloom_settings.low_frequency_boost_curvature += dt / 10.0;
            }
            bloom_settings.low_frequency_boost_curvature =
                bloom_settings.low_frequency_boost_curvature.clamp(0.0, 1.0);

            if keycode.pressed(KeyCode::KeyF) {
                bloom_settings.high_pass_frequency -= dt / 10.0;
            }
            if keycode.pressed(KeyCode::KeyR) {
                bloom_settings.high_pass_frequency += dt / 10.0;
            }
            bloom_settings.high_pass_frequency = bloom_settings.high_pass_frequency.clamp(0.0, 1.0);

            if keycode.pressed(KeyCode::KeyG) {
                bloom_settings.composite_mode = BloomCompositeMode::Additive;
            }
            if keycode.pressed(KeyCode::KeyT) {
                bloom_settings.composite_mode = BloomCompositeMode::EnergyConserving;
            }

            if keycode.pressed(KeyCode::KeyH) {
                bloom_settings.prefilter_settings.threshold -= dt;
            }
            if keycode.pressed(KeyCode::KeyY) {
                bloom_settings.prefilter_settings.threshold += dt;
            }
            bloom_settings.prefilter_settings.threshold =
                bloom_settings.prefilter_settings.threshold.max(0.0);

            if keycode.pressed(KeyCode::KeyJ) {
                bloom_settings.prefilter_settings.threshold_softness -= dt / 10.0;
            }
            if keycode.pressed(KeyCode::KeyU) {
                bloom_settings.prefilter_settings.threshold_softness += dt / 10.0;
            }
            bloom_settings.prefilter_settings.threshold_softness = bloom_settings
                .prefilter_settings
                .threshold_softness
                .clamp(0.0, 1.0);
        }

        (entity, None) => {
            *text = "Bloom: Off (Toggle: Space)".to_string();

            if keycode.just_pressed(KeyCode::Space) {
                commands.entity(entity).insert(BloomSettings::NATURAL);
            }
        }
    }
}

#[derive(Component)]
struct Bouncing;

fn bounce_spheres(time: Res<Time>, mut query: Query<&mut Transform, With<Bouncing>>) {
    for mut transform in query.iter_mut() {
        transform.translation.y =
            (transform.translation.x + transform.translation.z + time.elapsed_seconds()).sin();
    }
}