bevy-orbit-camera 0.3.0

A tiny Bevy plugin for an orbit camera controller.
Documentation 
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use crate::{control::OrbitControllerState, transform::LookTransform};
use bevy::prelude::*;

#[derive(Component)]
pub struct Marker;

#[derive(Resource)]
pub struct AutomaticRotation {
    pub enabled: bool,
    pub sensitivity: f32, // amount of radians to be rotated per second
}

impl Default for AutomaticRotation {
    fn default() -> Self {
        Self {
            enabled: false,
            sensitivity: 1.0,
        }
    }
}

pub(crate) fn update(
    mut cameras: Query<(&mut LookTransform, Option<&mut OrbitControllerState>), With<Marker>>,
    automatic_rotation: Res<AutomaticRotation>,
    time: Res<Time>,
) {
    if !automatic_rotation.enabled {
        return;
    }

    for (mut t, controller_state) in cameras.iter_mut() {
        let up = t.up.try_normalize().unwrap_or(Vec3::Y);
        let Some(mut forward) = (t.target - t.eye).try_normalize() else {
            continue;
        };
        let radius = t.radius();

        // radians per second * dt
        let yaw = automatic_rotation.sensitivity * time.delta_secs();

        forward = Quat::from_axis_angle(up, yaw) * forward;
        if let Some(mut controller_state) = controller_state {
            controller_state.yaw += yaw;
        }

        // eye = target - forward * radius  (forward is eye->target)
        t.eye = t.target - forward * radius;
    }
}