BevyRapier_howto_change_center_of_rotation_question

main.rs

use bevy::prelude::*;
use bevy_rapier2d::prelude::*;
use bevy_rapier2d::rapier::na::Vector2;
use nalgebra::{Isometry2};

fn main() {
    App::build()
        .insert_resource(WindowDescriptor {
            title: "Player Movement Example".to_string(),
            width: 1000.0,
            height: 1000.0,
            ..Default::default()
        })
        .add_plugins(DefaultPlugins)
        .add_startup_system(spawn_player.system())
        .add_system(player_movement.system())
        .add_plugin(RapierPhysicsPlugin::<NoUserData>::default())
        .run();
}

struct Player;

fn spawn_player(
    mut commands: Commands,
    mut materials: ResMut<Assets<ColorMaterial>>,
    mut rapier_config: ResMut<RapierConfiguration>,
) {
    // Set gravity to 0.0 and spawn camera.
    rapier_config.gravity = Vector2::zeros();
    commands
        .spawn()
        .insert_bundle(OrthographicCameraBundle::new_2d());

    let sprite_size_x = 100.0;
    let sprite_size_y = 40.0;

    // While we want our sprite to look ~40 px square, we want to keep the physics units smaller
    // to prevent float rounding problems. To do this, we set the scale factor in RapierConfiguration
    // and divide our sprite_size by the scale.
    rapier_config.scale = 20.0;
    let collider_size_x = sprite_size_x / rapier_config.scale;
    let collider_size_y = sprite_size_y / rapier_config.scale;

    // Spawn entity with `Player` struct as a component for access in movement query.
    commands
        .spawn()
        .insert_bundle(SpriteBundle {
            material: materials.add(Color::rgb(0.0, 0.0, 0.0).into()),
            sprite: Sprite::new(Vec2::new(sprite_size_x, sprite_size_y)),
            ..Default::default()
        })
        .insert_bundle(RigidBodyBundle {
            body_type: RigidBodyType::KinematicPositionBased,
            ..Default::default()
        })
        .insert_bundle(ColliderBundle {
            position: [collider_size_x / 2.0, collider_size_y / 2.0].into(),
            ..Default::default()
        })
        .insert(ColliderPositionSync::Discrete)
        .insert(ColliderDebugRender::with_id(0))
        .insert(Player);
}

fn player_movement(
    keyboard_input: Res<Input<KeyCode>>,
    rapier_parameters: Res<RapierConfiguration>,
    mut player_info: Query<(&Player, &mut RigidBodyPosition)>,
) {
    for (player, mut rbodypos) in player_info.iter_mut() {

        let mut next_rotation_angle = rbodypos.position.rotation.angle();
        if keyboard_input.pressed(KeyCode::Space)
        {
            next_rotation_angle += 0.06;
        }
        else
        {
            next_rotation_angle -= 0.06;
        }

        let clamped_angle = next_rotation_angle.clamp(-0.3, 0.3);
        rbodypos.next_position.rotation = Isometry2::rotation(clamped_angle).rotation;
    }
}