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
//! This example shows how to configure Physically Based Rendering (PBR) parameters.

use bevy::{asset::LoadState, prelude::*};

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

/// set up a simple 3D scene
fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
    asset_server: Res<AssetServer>,
) {
    let sphere_mesh = meshes.add(Sphere::new(0.45));
    // add entities to the world
    for y in -2..=2 {
        for x in -5..=5 {
            let x01 = (x + 5) as f32 / 10.0;
            let y01 = (y + 2) as f32 / 4.0;
            // sphere
            commands.spawn(PbrBundle {
                mesh: sphere_mesh.clone(),
                material: materials.add(StandardMaterial {
                    base_color: Srgba::hex("#ffd891").unwrap().into(),
                    // vary key PBR parameters on a grid of spheres to show the effect
                    metallic: y01,
                    perceptual_roughness: x01,
                    ..default()
                }),
                transform: Transform::from_xyz(x as f32, y as f32 + 0.5, 0.0),
                ..default()
            });
        }
    }
    // unlit sphere
    commands.spawn(PbrBundle {
        mesh: sphere_mesh,
        material: materials.add(StandardMaterial {
            base_color: Srgba::hex("#ffd891").unwrap().into(),
            // vary key PBR parameters on a grid of spheres to show the effect
            unlit: true,
            ..default()
        }),
        transform: Transform::from_xyz(-5.0, -2.5, 0.0),
        ..default()
    });

    commands.spawn(DirectionalLightBundle {
        transform: Transform::from_xyz(50.0, 50.0, 50.0).looking_at(Vec3::ZERO, Vec3::Y),
        directional_light: DirectionalLight {
            illuminance: 1_500.,
            ..default()
        },
        ..default()
    });

    // labels
    commands.spawn(
        TextBundle::from_section(
            "Perceptual Roughness",
            TextStyle {
                font_size: 36.0,
                ..default()
            },
        )
        .with_style(Style {
            position_type: PositionType::Absolute,
            top: Val::Px(20.0),
            left: Val::Px(100.0),
            ..default()
        }),
    );

    commands.spawn(TextBundle {
        text: Text::from_section(
            "Metallic",
            TextStyle {
                font_size: 36.0,
                ..default()
            },
        ),
        style: Style {
            position_type: PositionType::Absolute,
            top: Val::Px(130.0),
            right: Val::ZERO,
            ..default()
        },
        transform: Transform {
            rotation: Quat::from_rotation_z(std::f32::consts::PI / 2.0),
            ..default()
        },
        ..default()
    });

    commands.spawn((
        TextBundle::from_section(
            "Loading Environment Map...",
            TextStyle {
                font_size: 36.0,
                ..default()
            },
        )
        .with_style(Style {
            position_type: PositionType::Absolute,
            bottom: Val::Px(20.0),
            right: Val::Px(20.0),
            ..default()
        }),
        EnvironmentMapLabel,
    ));

    // camera
    commands.spawn((
        Camera3dBundle {
            transform: Transform::from_xyz(0.0, 0.0, 8.0).looking_at(Vec3::default(), Vec3::Y),
            projection: OrthographicProjection {
                scale: 0.01,
                ..default()
            }
            .into(),
            ..default()
        },
        EnvironmentMapLight {
            diffuse_map: asset_server.load("environment_maps/pisa_diffuse_rgb9e5_zstd.ktx2"),
            specular_map: asset_server.load("environment_maps/pisa_specular_rgb9e5_zstd.ktx2"),
            intensity: 900.0,
        },
    ));
}

fn environment_map_load_finish(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    environment_maps: Query<&EnvironmentMapLight>,
    label_query: Query<Entity, With<EnvironmentMapLabel>>,
) {
    if let Ok(environment_map) = environment_maps.get_single() {
        if asset_server.load_state(&environment_map.diffuse_map) == LoadState::Loaded
            && asset_server.load_state(&environment_map.specular_map) == LoadState::Loaded
        {
            if let Ok(label_entity) = label_query.get_single() {
                commands.entity(label_entity).despawn();
            }
        }
    }
}

#[derive(Component)]
struct EnvironmentMapLabel;