如何读取 bevy 中的鼠标动作?

How to read mouse motion in bevy?

我想制作第一人称相机。 我已经研究了其他几个实现的源代码,比如

https://github.com/mcpar-land/bevy_fly_camera

https://github.com/sburris0/bevy_flycam

但是当我自己实现它时(主要是复制粘贴 tbh)它无法编译,当在 git.

上使用最新的 bevy 版本时

编译输出:

error[E0277]: `*mut (usize, PhantomData<MouseMotion>)` cannot be sent between threads safely
   --> src/player_input.rs:151:13
    |
151 |     mut state: ResMut<State>,
    |                ^^^^^^^^^^^^^ `*mut (usize, PhantomData<MouseMotion>)` cannot be sent between threads safely
    | 
   ::: /home/luca/.cargo/git/checkouts/bevy-f7ffde730c324c74/89a41bc/crates/bevy_ecs/src/resource/resource_query.rs:66:26
    |
66  | pub struct ResMut<'a, T: Resource> {
    |                          -------- required by this bound in `bevy::prelude::ResMut`
    |
    = help: within `player_input::State<'_>`, the trait `Send` is not implemented for `*mut (usize, PhantomData<MouseMotion>)`
    = note: required because it appears within the type `Local<'_, (usize, PhantomData<MouseMotion>)>`
    = note: required because it appears within the type `bevy::prelude::EventReader<'_, MouseMotion>`
    = note: required because it appears within the type `player_input::State<'_>`
    = note: required because of the requirements on the impl of `Resource` for `player_input::State<'_>`

代码如下:

#[derive(Default)]
struct State<'a> {
    mouse_motion_event_reader: EventReader<'a, MouseMotion>,
}

fn mouse_motion_system(
    time: Res<Time>,

    mut state: ResMut<State>, //<-- IMPORTANT LINE (Line 151)

    mouse_motion_events: Res<Events<MouseMotion>>,
    mut query: Query<(&mut FlyCamera, &mut Transform)>,
) {
    //...
}

它只会在最新版本的 bevy 上抛出此错误,而不会在 0.4.0 版本上抛出此错误。

我是不是做错了什么或者我应该在 github 上打开一个问题,因为这是引擎的错误?

我需要做什么才能让它发挥作用?

您根本不应该在 State 中包含 EventReader。也许您想跟踪状态内的最后一个光标位置?

由于事件 API 已针对 Bevy 0.5 进行了简化,因此您只需要 EventReader 作为系统参数; mouse_motion_events: Res<Events<MouseMotion>>, 现已过时,可以替换为 mut mouse_motion_events: EventReader<MouseMotion>