README.md

bevy_transform64

A 64-bit version of Bevy Transform that enhances precision and minimizes floating-point errors in large-scale projects. This custom implementation substitutes Transform with DTransform and GlobalTransform with DGlobalTransform. The original GlobalTransform is retained for rendering purposes.

Usage

To integrate Bevy Transform64 into your project, follow these steps:

1. Add DTransformPlugin to your Bevy app:

App::new()
    .add_plugins(DefaultPlugins)
    .add_plugin(DTransformPlugin)
    .run();

2. Define the WorldOrigin resource and set it to the camera position or camera entity:

let camera = commands.spawn(Camera3dBundle {
    ..Default::default()
}).insert(DTransformBundle::from_transform(DTransform::from_xyz(5.0, 0.0, 5.0).looking_at(DVec3::ZERO, DVec3::Y))).id();
commands.insert_resource(WorldOrigin::Entity(camera));

3. Use DTransform for transformations and apply it to entities by inserting the DTransformBundle. For example, to create a cube with a DTransform:

let base_cube = commands.spawn(PbrBundle {
    mesh: mesh.clone(),
    material: material.clone(),
    visibility : Visibility::Visible,
    ..Default::default()
}).insert(DTransformBundle::from_transform(DTransform::from_xyz(0.0, 0.0, 0.0))).id();

Example

Here's an example demonstrating how to use Bevy Transform64:

use bevy::{prelude::*, math::DVec3};
use bevy_transform64::{prelude::*, WorldOrigin};
use bevy_egui::*;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_plugin(DTransformPlugin)
        .add_plugin(bevy_egui::EguiPlugin)
        .add_startup_systems((setup, apply_system_buffers).chain())
        .add_system(debug_gui)
        .add_system(fly)
        .add_system(camera_orbit)
        .run();
}

fn setup(
    mut commands: Commands,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {

    let mesh = meshes.add(Mesh::from(shape::Cube { size: 0.5 }));
    let material = materials.add(Color::rgb(0.8, 0.7, 0.6).into());

    let base_cube = commands.spawn(PbrBundle {
        mesh: mesh.clone(),
        material: material.clone(),
        visibility : Visibility::Visible,
        ..Default::default()
    }).insert(DTransformBundle::from_transform(DTransform::from_xyz(0.0, 0.0, 0.0))).id();

    let base_cube_2 = commands.spawn(PbrBundle {
        mesh: mesh.clone(),
        material: material.clone(),
        visibility : Visibility::Visible,
        ..Default::default()
    }).insert(DTransformBundle::from_transform(DTransform::from_xyz(0.0, 1.0, 0.0))).id();

    
    let base_cube_3 = commands.spawn(PbrBundle {
        mesh: mesh.clone(),
        material: material.clone(),
        visibility : Visibility::Visible,
        ..Default::default()
    }).insert(DTransformBundle::from_transform(DTransform::from_xyz(0.0, 1.0, 0.0))).id();

    commands.entity(base_cube).add_child(base_cube_2);
    commands.entity(base_cube_2).add_child(base_cube_3);

    let camera = commands.spawn(Camera3dBundle {
        ..Default::default()
    }).insert(DTransformBundle::from_transform(DTransform::from_xyz(5.0, 0.0, 5.0).looking_at(DVec3::ZERO, DVec3::Y))).id();

    commands.insert_resource(WorldOrigin::Entity(camera));
}

fn fly(
    mut transform : Query<&mut Transform, Without<Parent>>,
    mut dtransforms : Query<&mut DTransform, Without<Parent>>,
    time : Res<Time>
) {
    let speed = 10000.0;
    for mut dtransform in dtransforms.iter_mut() {
        dtransform.translation.y += (speed * time.delta_seconds()) as f64;
    }
}

fn camera_orbit(
    mut transform : Query<&mut Transform, With<Camera>>,
    mut dtransforms : Query<&mut DTransform, With<Camera>>,
    time : Res<Time>
) {
    let speed = 1.0;
    for mut dtransform in dtransforms.iter_mut() {
        let angle = speed * time.elapsed_seconds();
        let x = angle.cos() * 5.0;
        let z = angle.sin() * 5.0;
        dtransform.translation.x = x as f64;
        dtransform.translation.z = z as f64;
        let target = DVec3::new(0.0, dtransform.translation.y, 0.0);
        dtransform.look_at(target, DVec3::Y);
    }
}

fn debug_gui(
    mut egui_ctxs : Query<&mut EguiContext>,
    mut world_origin : ResMut<WorldOrigin>,
    mut dtransforms : Query<&DTransform>,
    mut transforms : Query<&Transform>,
) {
    egui::SidePanel::left("debug").show(egui_ctxs.single_mut().get_mut(), |ui| {
        ui.label("World Origin");
        ui.label(format!("{:?}", world_origin));

        if let WorldOrigin::Entity(entity) = *world_origin {
            // let pos = transforms.get(entity).unwrap().translation;
            let dpos = dtransforms.get(entity).unwrap().translation;

            // let dist = pos.length();
            let ddist = dpos.length();

            // ui.label(format!("f32 dist: {:?}", dist));
            ui.label(format!("f64 dist: {:?}", ddist));
        }        
    });
}