bevy_mouse_tracking_plugin 0.3.0

use bevy::prelude::*;

/// Plugin that tracks mouse motion.
pub struct MouseMotionPlugin;

pub use bevy::input::mouse::MouseMotion;

impl bevy::app::Plugin for MouseMotionPlugin {
    fn build(&self, app: &mut bevy::app::App) {
        app.insert_resource(MouseMotion { delta: Vec2::ZERO });
        app.add_system_to_stage(CoreStage::First, update_mouse_motion);
    }
}

fn update_mouse_motion(mut events: EventReader<MouseMotion>, mut res: ResMut<MouseMotion>) {
    let delta = events.iter().fold(Vec2::ZERO, |acc, e| acc + e.delta);
    *res = MouseMotion { delta };
}