docs/bevy/examples/gltf/query_gltf_primitives.rs 2.2 K · 68 lines · raw · history

1 //! This example demonstrates how to query a [`StandardMaterial`] within a glTF scene.
2 //! It is particularly useful for glTF scenes with a mesh that consists of multiple primitives.
3
4 use std::f32::consts::PI;
5
6 use bevy::{gltf::GltfMaterialName, mesh::VertexAttributeValues, prelude::*};
7
8 fn main() {
9 App::new()
10 .add_plugins(DefaultPlugins)
11 .add_systems(Startup, setup)
12 .add_systems(Update, find_top_material_and_mesh)
13 .run();
14 }
15
16 fn find_top_material_and_mesh(
17 mut materials: ResMut<Assets<StandardMaterial>>,
18 mut meshes: ResMut<Assets<Mesh>>,
19 time: Res<Time>,
20 mat_query: Query<(
21 &MeshMaterial3d<StandardMaterial>,
22 &Mesh3d,
23 &GltfMaterialName,
24 )>,
25 ) {
26 for (mat_handle, mesh_handle, name) in mat_query.iter() {
27 // locate a material by material name
28 if name.0 == "Top" {
29 if let Some(mut material) = materials.get_mut(mat_handle) {
30 if let Color::Hsla(ref mut hsla) = material.base_color {
31 *hsla = hsla.rotate_hue(time.delta_secs() * 100.0);
32 } else {
33 material.base_color = Color::from(Hsla::hsl(0.0, 0.9, 0.7));
34 }
35 }
36
37 if let Some(mut mesh) = meshes.get_mut(mesh_handle)
38 && let Some(VertexAttributeValues::Float32x3(positions)) =
39 mesh.attribute_mut(Mesh::ATTRIBUTE_POSITION)
40 {
41 for position in positions {
42 *position = (
43 position[0],
44 1.5 + 0.5 * ops::sin(time.elapsed_secs() / 2.0),
45 position[2],
46 )
47 .into();
48 }
49 }
50 }
51 }
52 }
53
54 fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
55 commands.spawn((
56 Camera3d::default(),
57 Transform::from_xyz(4.0, 4.0, 12.0).looking_at(Vec3::new(0.0, 0.0, 0.5), Vec3::Y),
58 ));
59
60 commands.spawn((
61 Transform::from_rotation(Quat::from_euler(EulerRot::ZYX, 0.0, 1.0, -PI / 4.)),
62 DirectionalLight::default(),
63 ));
64
65 commands.spawn(WorldAssetRoot(asset_server.load(
66 GltfAssetLabel::Scene(0).from_asset("models/GltfPrimitives/gltf_primitives.glb"),
67 )));
68 }