bevy_kneeboard/src/kneeboardplugin.rs

use std::f32::consts::PI;

use avian3d::{math::FRAC_PI_2, prelude::*};
use bevy::prelude::*;
use bevy_cef::prelude::*;
use bevy_mod_openxr::prelude::*;
use bevy_mod_xr::session::XrSessionCreated;
use bevy_pkv::{PersistentResourceAppExtensions, PkvStore};
use openxr::Path;
use serde::{Deserialize, Serialize};

use crate::{
    vrcontrollerplugin::{
        LeftController, LeftControllerActions, RightController, RightControllerActions,
    },
    vrplugin::{Headset, MainCamera, create_view_space},
};

#[derive(Component)]
pub struct Kneeboard;

#[derive(Resource, Serialize, Deserialize)]
pub struct KneeboardPosition {
    position: Vec3,
    rotation: Quat,
}

impl Default for KneeboardPosition {
    fn default() -> Self {
        Self {
            position: Vec3::new(0.15, -0.25, -0.40),
            rotation: Default::default(),
        }
    }
}

pub struct KneeboardPlugin;

impl Plugin for KneeboardPlugin {
    fn build(&self, app: &mut App) {
        app.add_plugins(PhysicsPlugins::default());
        app.add_plugins(CefPlugin {
            command_line_config: CommandLineConfig {
                switches: ["--no-zygote", "--no-sandbox"].to_vec(),
                ..Default::default()
            },
            ..Default::default()
        });
        app.insert_resource(PkvStore::new("Avii", "Kneeboard"))
            .init_persistent_resource::<KneeboardPosition>();
        app.add_systems(XrSessionCreated, spawn_kneeboard.after(create_view_space));
        app.add_systems(Update, gaze.run_if(openxr_session_running));
        app.add_systems(Update, move_keyboard.run_if(openxr_session_running));
        app.add_systems(Update, position_kneeboard.after(move_keyboard));
        app.add_systems(Update, sync_camera_with_kneeboard.after(position_kneeboard));
        app.add_systems(Update, scroll_handler.run_if(openxr_session_running));
    }
}

fn sync_camera_with_kneeboard(
    kneeboard: Query<&Transform, With<Kneeboard>>,
    mut cameras: Query<&mut Transform, (With<MainCamera>, Without<Kneeboard>)>,
) {
    let Ok(kneeboard) = kneeboard.single() else {
        return;
    };

    let Ok(mut camera) = cameras.single_mut() else {
        return;
    };

    let mut transform = *kneeboard;

    transform.translation -= kneeboard.back().normalize() * 0.35;
    transform.rotation *= Quat::from_axis_angle(Dir3::X.normalize(), PI)
        * Quat::from_axis_angle(Dir3::Z.normalize(), PI);

    *camera = transform;
}

fn scroll_handler(
    session: Res<OxrSession>,
    right: Res<RightControllerActions>,
    browsers: NonSend<Browsers>,
    webviews: Query<Entity, With<WebviewSource>>,
) {
    let Ok(thumbstick) = right.thumbstick.state(&session, Path::NULL) else {
        return;
    };

    let delta = Vec2::new(thumbstick.current_state.x, thumbstick.current_state.y) * 8.0;

    for webview in webviews.iter() {
        browsers.send_mouse_wheel(&webview, Vec2::ZERO, delta);
    }
}

fn position_kneeboard(
    mut transform: Query<&mut Transform, With<Kneeboard>>,
    kneeboard: Res<KneeboardPosition>,
) {
    let Ok(mut transform) = transform.single_mut() else {
        return;
    };

    transform.translation = kneeboard.position;
    transform.rotation = kneeboard.rotation;
}

fn move_keyboard(
    session: Res<OxrSession>,
    left: Res<LeftControllerActions>,
    right: Res<RightControllerActions>,
    left_transform: Query<&Transform, (With<LeftController>, Without<RightController>)>,
    right_transform: Query<&Transform, (With<RightController>, Without<LeftController>)>,
    mut kneeboard: ResMut<KneeboardPosition>,
) {
    let rot_offset: Quat = Quat::from_axis_angle(Vec3::new(1.0, 0.0, 0.0), FRAC_PI_2)
        * Quat::from_axis_angle(Vec3::new(0.0, 0.0, 1.0), PI);

    if let Ok(trigger_state) = left.squeeze_click.state(&session, Path::NULL)
        && trigger_state.current_state
    {
        let Ok(transform) = left_transform.single() else {
            return;
        };

        let pos_offset = transform.up().normalize() * -0.1;
        kneeboard.position = transform.translation + pos_offset;
        kneeboard.rotation = transform.rotation * rot_offset;
    }

    if let Ok(trigger_state) = right.squeeze_click.state(&session, Path::NULL)
        && trigger_state.current_state
    {
        let Ok(transform) = right_transform.single() else {
            return;
        };

        let pos_offset = transform.up().normalize() * -0.1;

        kneeboard.position = transform.translation + pos_offset;
        kneeboard.rotation = transform.rotation * rot_offset;
    }
}

fn spawn_kneeboard(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<WebviewExtendStandardMaterial>>,
    position: Res<KneeboardPosition>,
) {
    commands.spawn((
        RigidBody::Static,
        WebviewSource::new("http://localhost:7878/"),
        WebviewSize(Vec2::new(210.0 * 3.5, 279.0 * 3.5)),
        Collider::cuboid(0.210, 0.279, 0.01),
        CollidingEntities::default(),
        Mesh3d(meshes.add(Cuboid::new(0.210, 0.279, 0.01))),
        MeshMaterial3d(materials.add(WebviewExtendStandardMaterial {
            base: StandardMaterial {
                unlit: true,
                ..default()
            },
            ..Default::default()
        })),
        Transform::from_translation(position.position).rotate(position.rotation),
        Kneeboard,
    ));
}

fn gaze(
    material_handles: Query<&MeshMaterial3d<WebviewExtendStandardMaterial>, With<Kneeboard>>,
    mut materials: ResMut<Assets<WebviewExtendStandardMaterial>>,
    position: Res<KneeboardPosition>,
    head_query: Query<&Transform, With<Headset>>,
) {
    let head = head_query.single().expect("a head to exist");

    let facing = head.forward().normalize();
    let to_target = (position.position - head.translation).normalize();
    let dot = facing.dot(to_target);
    let cos_fov_angle: f32 = (35.0f32 / 2.0f32).to_radians().cos();

    let mut alpha = 1.0;
    if dot < cos_fov_angle {
        alpha = 0.0;
    }

    for material_handle in material_handles.iter() {
        if let Some(material) = materials.get_mut(material_handle)
            && let Color::LinearRgba(ref mut rgba) = material.base.base_color
        {
            rgba.alpha = alpha;
        }
    }
}