cyber_rider/src/bike.rs

use std::fmt::Debug;

use bevy::prelude::{shape::UVSphere as Tire, *};
use bevy_rapier3d::{
    geometry::Group,
    prelude::{
        Ccd, Collider, ColliderMassProperties, CollisionGroups, Damping, ExternalForce, Friction,
        ImpulseJoint, PrismaticJointBuilder, Restitution, RigidBody, Sleeping,
        TransformInterpolation, Velocity,
    },
};

use crate::planet::PLANET_RADIUS;

type Meshterial<'a> = (
    ResMut<'a, Assets<Mesh>>,
    ResMut<'a, Assets<StandardMaterial>>,
);

#[derive(Component)]
pub struct CyberBikeBody;

#[derive(Component)]
pub struct CyberBikeCollider;

#[derive(Component, Debug)]
pub struct CyberBikeModel;

#[derive(Debug, Component)]
pub struct CyberWheel;

#[derive(Component, Debug, Default, Clone, Copy)]
pub struct CyberBikeControl {
    pub error_sum: f32,
    pub prev_error: f32,
}

#[derive(Resource, Reflect)]
#[reflect(Resource)]
pub struct WheelConfig {
    pub front_forward: f32,
    pub front_stance: f32,
    pub rear_back: f32,
    pub y: f32,
    pub limits: [f32; 2],
    pub stiffness: f32,
    pub damping: f32,
    pub radius: f32,
}

impl Default for WheelConfig {
    fn default() -> Self {
        Self {
            front_forward: 0.9,
            front_stance: 0.65,
            rear_back: 1.1,
            y: -1.5,
            limits: [-1.0, 0.0],
            stiffness: 80.0,
            damping: 0.6,
            radius: 0.4,
        }
    }
}

const BIKE_BODY_COLLISION_GROUP: (Group, Group) = (Group::GROUP_1, Group::GROUP_1);
const BIKE_WHEEL_COLLISION_GROUP: (Group, Group) = (Group::GROUP_10, Group::GROUP_10);

fn spawn_cyberbike(
    mut commands: Commands,
    asset_server: Res<AssetServer>,
    wheel_conf: Res<WheelConfig>,
    mut meshterials: Meshterial,
) {
    let altitude = PLANET_RADIUS - 220.0;

    let mut xform = Transform::from_translation(Vec3::X * altitude)
        .with_rotation(Quat::from_axis_angle(Vec3::Z, -89.0f32.to_radians()));
    //.with_rotation(Quat::from_axis_angle(Vec3::X, 140.0f32.to_radians()));

    let right = xform.right() * 350.0;
    xform.translation += right;

    let damping = Damping {
        angular_damping: 0.5,
        linear_damping: 0.1,
    };
    let not_sleeping = Sleeping::disabled();
    let ccd = Ccd { enabled: true };

    let bcollider_shape =
        Collider::capsule(Vec3::new(0.0, 0.0, -1.0), Vec3::new(0.0, 0.0, 1.0), 0.50);

    let friction = Friction {
        coefficient: 0.0,
        ..Default::default()
    };

    let restitution = Restitution {
        coefficient: 0.0,
        ..Default::default()
    };

    let mass_properties = ColliderMassProperties::Density(0.2);

    let (membership, filter) = BIKE_BODY_COLLISION_GROUP;
    let bike_collision_group = CollisionGroups::new(membership, filter);

    let scene = asset_server.load("cb-no-y_up.glb#Scene0");

    let spatialbundle = SpatialBundle {
        transform: xform,
        ..Default::default()
    };

    let bike = commands
        .spawn(RigidBody::Dynamic)
        .insert(spatialbundle)
        .insert((
            bcollider_shape,
            bike_collision_group,
            mass_properties,
            damping,
            restitution,
            friction,
            not_sleeping,
            ccd,
        ))
        .insert(TransformInterpolation {
            start: None,
            end: None,
        })
        .insert(Velocity::zero())
        .insert(ExternalForce::default())
        .insert(CyberBikeCollider)
        .with_children(|rider| {
            rider.spawn(SceneBundle {
                scene,
                ..Default::default()
            });
        })
        .insert(CyberBikeModel)
        .insert(CyberBikeBody)
        .insert(CyberBikeControl::default())
        .id();

    spawn_tires(&mut commands, &xform, bike, &wheel_conf, &mut meshterials);
}

fn re_tire(
    mut commands: Commands,
    wheel_conf: ResMut<WheelConfig>,
    mut meshterials: Meshterial,
    bquery: Query<(Entity, &Transform), With<CyberBikeBody>>,
    wheels: Query<Entity, With<CyberWheel>>,
) {
    // we fuck with values in the egui inspector
    let (bike, xform) = bquery.single();
    if wheel_conf.is_changed() {
        for wheel in wheels.iter() {
            commands.entity(wheel).despawn_recursive();
        }
        spawn_tires(&mut commands, xform, bike, &wheel_conf, &mut meshterials);
    }
}

fn spawn_tires(
    commands: &mut Commands,
    xform: &Transform,
    bike: Entity,
    conf: &WheelConfig,
    meshterials: &mut Meshterial,
) {
    // re-set the collision group
    let (membership, filter) = BIKE_WHEEL_COLLISION_GROUP;
    let wheels_collision_group = CollisionGroups::new(membership, filter);
    let wheel_y = conf.y;
    let wheel_rad = conf.radius;
    let stiffness = conf.stiffness;
    let not_sleeping = Sleeping::disabled();
    let ccd = Ccd { enabled: true };
    let limits = conf.limits;
    let (meshes, materials) = meshterials;

    let tire = Tire {
        radius: wheel_rad,
        ..Default::default()
    };
    let material = StandardMaterial {
        base_color: Color::Rgba {
            red: 0.01,
            green: 0.01,
            blue: 0.01,
            alpha: 1.0,
        },
        alpha_mode: AlphaMode::Opaque,
        perceptual_roughness: 0.5,
        ..Default::default()
    };

    let pbr_bundle = PbrBundle {
        material: materials.add(material),
        mesh: meshes.add(Mesh::from(tire)),
        ..Default::default()
    };

    let mut wheel_poses = Vec::with_capacity(3);

    // left front
    {
        let wheel_x = -conf.front_stance;
        let wheel_z = -conf.front_forward;
        let offset = Vec3::new(wheel_x, wheel_y, wheel_z);
        wheel_poses.push(offset);
    }

    // right front
    {
        let wheel_x = conf.front_stance;
        let wheel_z = -conf.front_forward;
        let offset = Vec3::new(wheel_x, wheel_y, wheel_z);
        wheel_poses.push(offset);
    }

    // rear
    {
        let wheel_x = 0.0;
        let wheel_z = conf.rear_back;
        let offset = Vec3::new(wheel_x, wheel_y, wheel_z);
        wheel_poses.push(offset);
    }

    for offset in wheel_poses {
        let trans = xform.translation + offset;
        let wheel_pos_in_world = Transform::from_rotation(xform.rotation).with_translation(trans);
        let wheel_damping = Damping {
            linear_damping: 0.8,
            ..Default::default()
        };
        let wheel_collider = Collider::ball(wheel_rad);
        let mass_props = ColliderMassProperties::Density(0.001);

        let damping = conf.damping;
        let prismatic = PrismaticJointBuilder::new(Vec3::Y)
            .local_anchor1(offset)
            .limits(limits)
            .motor_position(-1.0, stiffness, damping);
        let joint = ImpulseJoint::new(bike, prismatic);

        let spatial_bundle = SpatialBundle {
            transform: wheel_pos_in_world,
            ..Default::default()
        };

        let tire_spundle = SpatialBundle {
            transform: Transform::IDENTITY,
            ..Default::default()
        };

        commands
            .spawn(RigidBody::Dynamic)
            .insert(spatial_bundle)
            .insert((
                wheel_collider,
                mass_props,
                wheel_damping,
                ccd,
                not_sleeping,
                joint,
                wheels_collision_group,
            ))
            .with_children(|wheel| {
                wheel.spawn(tire_spundle).insert(pbr_bundle.clone()).insert(
                    TransformInterpolation {
                        start: None,
                        end: None,
                    },
                );
            })
            .insert(TransformInterpolation {
                start: None,
                end: None,
            })
            .insert(CyberWheel);
    }
}

pub struct CyberBikePlugin;
impl Plugin for CyberBikePlugin {
    fn build(&self, app: &mut App) {
        app.insert_resource(WheelConfig::default())
            .register_type::<WheelConfig>()
            .add_startup_system_to_stage(StartupStage::PostStartup, spawn_cyberbike)
            .add_system(re_tire);
    }
}