91 lines
3.0 KiB
Rust
91 lines
3.0 KiB
Rust
use bevy::{
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prelude::*,
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render::{
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camera::{Camera, VisibleEntities},
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mesh::shape,
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},
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};
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/// This example visualizes camera z-ordering by setting the material of rotating cubes to their distance from the camera
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fn main() {
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App::build()
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.add_plugins(DefaultPlugins)
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.add_startup_system(setup)
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.add_system(rotator_system)
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.add_system(camera_order_color_system)
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.run();
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}
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struct Rotator;
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/// rotates the parent, which will result in the child also rotating
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fn rotator_system(time: Res<Time>, mut query: Query<&mut Transform, With<Rotator>>) {
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for mut transform in query.iter_mut() {
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transform.rotation *= Quat::from_rotation_x(3.0 * time.delta_seconds());
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}
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}
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fn camera_order_color_system(
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mut materials: ResMut<Assets<StandardMaterial>>,
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camera_query: Query<&VisibleEntities, With<Camera>>,
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material_query: Query<&Handle<StandardMaterial>>,
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) {
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for visible_entities in camera_query.iter() {
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for visible_entity in visible_entities.iter() {
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if let Ok(material_handle) = material_query.get(visible_entity.entity) {
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let material = materials.get_mut(&*material_handle).unwrap();
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let value = 1.0 - (visible_entity.order.0 - 10.0) / 7.0;
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material.albedo = Color::rgb(value, value, value);
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}
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}
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}
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}
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fn setup(
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commands: &mut Commands,
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mut meshes: ResMut<Assets<Mesh>>,
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mut materials: ResMut<Assets<StandardMaterial>>,
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) {
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let cube_handle = meshes.add(Mesh::from(shape::Cube { size: 2.0 }));
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commands
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// parent cube
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.spawn(PbrBundle {
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mesh: cube_handle.clone(),
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material: materials.add(StandardMaterial {
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shaded: false,
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..Default::default()
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}),
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transform: Transform::from_translation(Vec3::new(0.0, 0.0, 1.0)),
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..Default::default()
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})
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.with(Rotator)
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.with_children(|parent| {
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// child cubes
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parent
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.spawn(PbrBundle {
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mesh: cube_handle.clone(),
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material: materials.add(StandardMaterial {
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shaded: false,
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..Default::default()
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}),
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transform: Transform::from_translation(Vec3::new(0.0, 3.0, 0.0)),
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..Default::default()
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})
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.spawn(PbrBundle {
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mesh: cube_handle,
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material: materials.add(StandardMaterial {
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shaded: false,
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..Default::default()
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}),
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transform: Transform::from_translation(Vec3::new(0.0, -3.0, 0.0)),
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..Default::default()
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});
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})
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// camera
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.spawn(Camera3dBundle {
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transform: Transform::from_translation(Vec3::new(5.0, 10.0, 10.0))
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.looking_at(Vec3::default(), Vec3::unit_y()),
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..Default::default()
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});
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}
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