examples/entities/
entity_basics.rs

1use crate::z_ignore_test_common::*;
2
3use flecs_ecs::prelude::*;
4
5#[derive(Debug, Component)]
6pub struct Position {
7    pub x: f32,
8    pub y: f32,
9}
10
11#[derive(Debug, Component)]
12pub struct Velocity {
13    pub x: f32,
14    pub y: f32,
15}
16
17#[derive(Component)]
18pub struct Walking;
19
20fn main() {
21    let world = World::new();
22
23    // Create an entity with name Bob
24    let bob = world
25        .entity_named("Bob")
26        // The set operation finds or creates a component, and sets it.
27        // Components are automatically registered with the world
28        .set(Position { x: 10.0, y: 20.0 })
29        // The add operation adds a component without setting a value. This is
30        // useful for tags, or when adding a component with its default value.
31        .add(Walking);
32
33    // Get the value for the Position component
34    // - get panics if the component is not present, use try_get for a non-panicking version which does not run the callback.
35    // - or use Option to handle the individual component missing.
36    bob.get::<Option<&Position>>(|pos| {
37        if let Some(pos) = pos {
38            println!("Bob's position: {pos:?}");
39        }
40    });
41
42    // Overwrite the value of the Position component
43    bob.set(Position { x: 20.0, y: 30.0 });
44
45    // Create another named entity
46    let alice = world
47        .entity_named("Alice")
48        .set(Position { x: 10.0, y: 20.0 });
49
50    // Add a tag after entity is created
51    alice.add(Walking);
52
53    // Print all of the components the entity has. This will output:
54    //    Position, Walking, (Identifier,Name)
55    println!("[{}]", alice.archetype());
56
57    // Remove tag
58    alice.remove(Walking);
59
60    // Iterate all entities with position
61    world.each_entity::<&Position>(|entity, pos| {
62        println!("{} has {:?}", entity.name(), pos);
63    });
64
65    // Output:
66    //  Bob's position: Position { x: 10.0, y: 20.0 }
67    //  [Position, Walking, (Identifier,Name)]
68    //  Alice has Position { x: 10.0, y: 20.0 }
69    //  Bob has Position { x: 20.0, y: 30.0 }
70}
71
72#[cfg(feature = "flecs_nightly_tests")]
73#[test]
74fn test() {
75    let output_capture = OutputCapture::capture().unwrap();
76    main();
77    output_capture.test("entity_basics".to_string());
78}
examples/entities/entity_basics.rs

examples/entities/
entity_basics.rs
