3fc2bd71ea
# Objective This example is really confusing to look at and tell at a glance whether it's broken or not. It's displaying a strange shape -- a cube with two vertices stretched in a couple dimensions at an odd angle, and doing its vertex position modification in a way where the intent isn't obvious. ## Solution - Change the gltf geometry so that the object is a recognizable regular shape - Change the vertex modification so that the entire cube top is being "lifted" from the cube - Adjust colors, lighting, and camera location so we can see what's going on - Also remove some irrelevant shadow and environment map setup ## Before  ## After <img width="1280" alt="image" src="https://github.com/user-attachments/assets/59cab60d-efbc-47c3-8688-e4544b462421">
70 lines
2.3 KiB
Rust
70 lines
2.3 KiB
Rust
//! This example demonstrates how to query a [`StandardMaterial`] within a glTF scene.
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//! It is particularly useful for glTF scenes with a mesh that consists of multiple primitives.
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use std::f32::consts::PI;
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use bevy::{gltf::GltfMaterialName, prelude::*, render::mesh::VertexAttributeValues};
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fn main() {
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App::new()
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.add_plugins(DefaultPlugins)
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.add_systems(Startup, setup)
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.add_systems(Update, find_top_material_and_mesh)
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.run();
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}
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fn find_top_material_and_mesh(
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mut materials: ResMut<Assets<StandardMaterial>>,
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mut meshes: ResMut<Assets<Mesh>>,
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time: Res<Time>,
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mat_query: Query<(
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&MeshMaterial3d<StandardMaterial>,
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&Mesh3d,
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&GltfMaterialName,
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)>,
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) {
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for (mat_handle, mesh_handle, name) in mat_query.iter() {
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// locate a material by material name
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if name.0 == "Top" {
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if let Some(material) = materials.get_mut(mat_handle) {
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if let Color::Hsla(ref mut hsla) = material.base_color {
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*hsla = hsla.rotate_hue(time.delta_secs() * 100.0);
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} else {
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material.base_color = Color::from(Hsla::hsl(0.0, 0.9, 0.7));
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}
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}
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if let Some(mesh) = meshes.get_mut(mesh_handle) {
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if let Some(VertexAttributeValues::Float32x3(positions)) =
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mesh.attribute_mut(Mesh::ATTRIBUTE_POSITION)
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{
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for position in positions {
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*position = (
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position[0],
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1.5 + 0.5 * ops::sin(time.elapsed_secs() / 2.0),
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position[2],
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)
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.into();
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}
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}
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}
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}
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}
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}
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fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
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commands.spawn((
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Camera3d::default(),
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Transform::from_xyz(4.0, 4.0, 12.0).looking_at(Vec3::new(0.0, 0.0, 0.5), Vec3::Y),
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));
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commands.spawn((
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Transform::from_rotation(Quat::from_euler(EulerRot::ZYX, 0.0, 1.0, -PI / 4.)),
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DirectionalLight::default(),
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));
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commands.spawn(SceneRoot(asset_server.load(
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GltfAssetLabel::Scene(0).from_asset("models/GltfPrimitives/gltf_primitives.glb"),
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)));
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}
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