bevy_fixed_update_task 0.1.2

A fixed update for bevy, unthrottled from bevy's default update loop.
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164

use std::time::Duration;

use bevy::{prelude::*, time::TimeUpdateStrategy};
use bevy_fixed_update_task::{
    BackgroundFixedUpdatePlugin, SubstepCount, TaskToRenderTime, TaskWorker, TaskWorkerTrait,
    Timestep,
};

#[test]
pub fn minimal_move_lose_time() {
    let mut app = App::new();

    app.add_plugins((
        MinimalPlugins,
        BackgroundFixedUpdatePlugin::<TaskWorkerTraitImpl>::default(),
    ));

    app.add_systems(Startup, |mut commands: Commands| {
        commands.insert_resource(TimeUpdateStrategy::ManualDuration(Duration::from_secs_f32(
            1.0,
        )));
        commands.spawn((
            Timestep {
                timestep: Duration::from_secs_f32(1.0 / 60.0),
            },
            TaskWorker {
                worker: TaskWorkerTraitImpl {},
            },
            WriteBackCount::default(),
        ));
        commands.spawn((ToSimulate, Transform::default()));
    });

    for _ in 0..11 {
        app.update();
    }
    let world = app.world_mut();
    assert_eq!(
        10,
        world
            .query::<&WriteBackCount>()
            .iter(world)
            .next()
            .unwrap()
            .0
    );
    let task_to_render_time = world
        .query::<&TaskToRenderTime>()
        .iter(world)
        .next()
        .unwrap();
    assert!(
        2.33 < task_to_render_time.diff,
        "Task to render time should be greater than 2.33 (task behind render time), but it is: {}",
        task_to_render_time.diff
    );
}
#[test]
pub fn minimal_move_catch_back_time() {
    let mut app = App::new();

    app.add_plugins((
        MinimalPlugins,
        BackgroundFixedUpdatePlugin::<TaskWorkerTraitImpl>::default(),
    ));

    app.add_systems(Startup, |mut commands: Commands| {
        commands.insert_resource(TimeUpdateStrategy::ManualDuration(Duration::from_secs_f32(
            1.0 / 30.0,
        )));
        commands.spawn((
            Timestep {
                timestep: Duration::from_secs_f64(1.0 / 60.0),
            },
            SubstepCount(60),
            TaskWorker {
                worker: TaskWorkerTraitImpl {},
            },
            WriteBackCount::default(),
        ));
        commands.spawn((ToSimulate, Transform::default()));
    });

    for _ in 0..121 {
        app.update();
    }
    let world = app.world_mut();
    assert_eq!(
        4,
        world
            .query::<&WriteBackCount>()
            .iter(world)
            .next()
            .unwrap()
            .0
    );
    let task_to_render_time = world
        .query::<&TaskToRenderTime>()
        .iter(world)
        .next()
        .unwrap();
    assert!(
        task_to_render_time.diff < 0.01,
        "Task to render time should be lower than 0.01, but it is: {}",
        task_to_render_time.diff
    );
}

#[derive(Component, Default)]
pub struct WriteBackCount(pub usize);

#[derive(Component)]
pub struct ToSimulate;

#[derive(Debug, Clone, Default)]
pub struct TaskWorkerTraitImpl;

impl TaskWorkerTrait for TaskWorkerTraitImpl {
    type TaskExtractedData = TaskExtractedData;
    type TaskResultPure = TaskExtractedData;

    fn work(
        &self,
        _worker: Entity,
        mut input: TaskExtractedData,
        timestep: Duration,
        substep_count: u32,
    ) -> Self::TaskResultPure {
        for i in input.positions.iter_mut() {
            i.1.translation += Vec3::new(timestep.as_secs_f32() * substep_count as f32, 0.0, 0.0);
        }
        input
    }

    fn extract(&self, _worker_entity: Entity, world: &mut World) -> TaskExtractedData {
        let positions = world
            .query_filtered::<(Entity, &Transform), With<ToSimulate>>()
            .iter(world)
            .map(|(e, t)| (e, t.clone()))
            .collect::<Vec<_>>();
        TaskExtractedData { positions }
    }

    fn write_back(
        &self,
        worker_entity: Entity,
        result: bevy_fixed_update_task::TaskResult<Self>,
        world: &mut World,
    ) {
        for (e, t) in result.result_raw.result.positions.iter() {
            world.get_mut::<Transform>(*e).unwrap().translation = t.translation;
        }
        world
            .query::<&mut WriteBackCount>()
            .get_mut(world, worker_entity)
            .unwrap()
            .0 += 1;
    }
}

#[derive(Debug, Component, Clone)]
pub struct TaskExtractedData {
    pub positions: Vec<(Entity, Transform)>,
}