bevy/examples/3d/z_sort_debug.rs
Carter Anderson 81b53d15d4 Make Commands and World apis consistent (#1703)
Resolves #1253 #1562

This makes the Commands apis consistent with World apis. This moves to a "type state" pattern (like World) where the "current entity" is stored in an `EntityCommands` builder.

In general this tends to cuts down on indentation and line count. It comes at the cost of needing to type `commands` more and adding more semicolons to terminate expressions.

I also added `spawn_bundle` to Commands because this is a common enough operation that I think its worth providing a shorthand.
2021-03-23 00:23:40 +00:00

89 lines
2.9 KiB
Rust

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