bevy_lagrange

Work in progress. This crate is in active development and not subject to semver stability guarantees. APIs will change without notice between commits. Do not depend on this in production code yet.

A camera controller for Bevy that combines smooth orbit controls with event-driven camera operations — zoom-to-fit, queued animations, and a debug overlay for fit targets.

Features

• Smooth orbit, pan, and zoom with configurable limits
• Zoom-to-fit, look-at, and queued camera animations with easing
• Event-driven control with full lifecycle events for sequencing
• Orthographic and perspective projection, multi-viewport, render-to-texture
• Touch, trackpad, and bevy_egui support
• Debug overlay for fit targets (optional fit_overlay feature)

Quick Start

Add the plugin and spawn a camera:

use bevy::prelude::*;
use bevy_lagrange::LagrangePlugin;
use bevy_lagrange::OrbitCam;

fn main() {
    App::new()
        .add_plugins(DefaultPlugins)
        .add_plugins(LagrangePlugin)
        .add_systems(Startup, setup)
        .run();
}

fn setup(mut commands: Commands) {
    commands.spawn((
        Transform::from_translation(Vec3::new(0.0, 1.5, 5.0)),
        OrbitCam::default(),
    ));
}

OrbitCam automatically requires Camera3d. Out of the box you get orbit, pan, and zoom with smoothing. For perspective cameras, the default near clip plane scales with orbit radius so close-up zooming does not clip away the target.

Controls

Default mouse controls:

Input	Action
Left Mouse	Orbit
Right Mouse	Pan
Scroll Wheel	Zoom

Default touch controls:

Input	Action
One finger	Orbit
Two fingers	Pan
Pinch	Zoom

All controls are configurable via OrbitCam fields — buttons, modifiers, sensitivity, smoothness, and limits.

Event-Driven Camera Control

Enable the fit_overlay feature:

bevy_lagrange = { version = "...", features = ["fit_overlay"] }

Zoom-to-fit

Frame a target entity in the camera view:

commands.trigger(
    ZoomToFit::new(camera, target)
        .margin(0.15)
        .duration(Duration::from_millis(800))
        .easing(EaseFunction::CubicOut),
);

Look at

Rotate the camera in place to face a target:

commands.trigger(
    LookAt::new(camera, target)
        .duration(Duration::from_millis(600)),
);

Animate to a specific orientation

Animate to a chosen yaw/pitch while framing the target:

commands.trigger(
    AnimateToFit::new(camera, target)
        .yaw(PI / 4.0)
        .pitch(PI / 6.0)
        .duration(Duration::from_millis(1200)),
);

Queued animations

Chain multiple movements into a sequence:

commands.trigger(PlayAnimation::new(camera, [
    CameraMove::ToOrbit {
        focus: Vec3::ZERO,
        yaw: 0.0,
        pitch: 0.5,
        radius: 5.0,
        duration: Duration::from_millis(800),
        easing: EaseFunction::CubicOut,
    },
]));

All operations support instant (Duration::ZERO) and animated paths with full lifecycle events for sequencing.

Cargo Features

Feature	Default	Description
fit_overlay	no	Zoom-to-fit, camera animations, event-driven control, and debug overlay
bevy_egui	no	Prevents camera movement when interacting with egui windows

Version Compatibility

bevy_lagrange	Bevy
0.0.3	0.18

Credits

• Plonq — bevy_lagrange builds on bevy_panorbit_camera, with permission

License

All code in this repository is dual-licensed under either:

• MIT License (LICENSE-MIT or http://opensource.org/licenses/MIT)
• Apache License, Version 2.0 (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)

at your option.