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//! Minimal example of spawning meshes and a floating origin camera.
use bevy::prelude::*;
use bevy_math::DVec3;
use big_space::prelude::*;
// Spawn the camera and mesh really, stupidly, far from the origin .
const BIG_DISTANCE: f64 = 1_000_000_000_000_000_000.0;
fn main() {
App::new()
.add_plugins((
DefaultPlugins.build().disable::<TransformPlugin>(),
BigSpaceDefaultPlugins,
))
.add_systems(Startup, setup_scene)
.run();
}
fn setup_scene(
mut commands: Commands,
asset_server: Res<AssetServer>,
mut meshes: ResMut<Assets<Mesh>>,
mut materials: ResMut<Assets<StandardMaterial>>,
) {
// Using `spawn_big_space` helps you avoid mistakes when building hierarchies.
//
// A world can have multiple independent BigSpaces, with their own floating origins. This can
// come in handy if you want to have two cameras very far from each other, rendering at the same
// time as split screen, or portals.
commands.spawn_big_space_default(|root_grid| {
// Because BIG_DISTANCE is so large, we want to avoid using bevy's f32 transforms alone and
// experience rounding errors. Instead, we use this helper to convert f64 position into a
// grid cell and f32 offset.
let (grid_cell, cell_offset) = root_grid
.grid()
.translation_to_grid(DVec3::splat(BIG_DISTANCE));
// `spawn_spatial` will spawn a high-precision spatial entity with floating origin support.
root_grid.spawn_spatial(DirectionalLight::default());
// Spawn a sphere mesh with high precision.
root_grid.spawn_spatial((
Mesh3d(meshes.add(Sphere::default())),
MeshMaterial3d(materials.add(Color::WHITE)),
Transform::from_translation(cell_offset),
grid_cell,
));
// Spawning low-precision entities (without a GridCell) as children of high-precision
// entities (with a GridCell), is also supported. We demonstrate this here by loading in a
// GLTF scene, which will be added as a child of this entity using low precision Transforms.
root_grid.spawn_spatial((
SceneRoot(asset_server.load("models/low_poly_spaceship/scene.gltf#Scene0")),
Transform::from_translation(cell_offset - 10.0),
grid_cell,
));
// Any spatial entity can be the floating origin. Attaching it to the camera ensures the
// camera will never see floating point precision rendering artifacts.
root_grid.spawn_spatial((
Camera3d::default(),
Transform::from_translation(cell_offset + Vec3::new(0.0, 0.0, 10.0)),
grid_cell,
FloatingOrigin,
BigSpaceCameraController::default(),
));
});
}