jiggle-game

A physics sandbox/game prototype built with Bevy, featuring a soft-body car body (inspired by JellyCar), spring-connected tires, and an in-progress editor mode. This project is heavily inspired by Walaber Entertainment's Physics of JellyCar: Soft Body Physics Explained video.

What This Project Currently Does

• Starts in a main menu with Play and Editor buttons.
• In Play mode, spawns:
  • one deformable car body (point-mass + spring model)
  • two deformable tires
  • spring-based joints between body and tires
  • a static floor shape
• Runs physics systems for point masses, springs, joints, and collisions.
• Includes rendering/debug components for points/springs.
• Supports an editor plugin with scene/UI/input systems under active development.

Tech Stack

• Rust (edition 2024)
• Bevy 0.18
• bevy-inspector-egui
• serde + serde_json

Prerequisites

• Rust toolchain (stable): rustup, cargo
• On Linux, native libraries required by Bevy (windowing/audio stack)

Start in development mode

cargo run

Release build

cargo run --release

Compile only

cargo build

App States

Defined in src/states.rs:

• AppState
  • MainMenu (default)
  • Editor
  • InGame
• GameState (sub-state of InGame)
  • Running (default)
  • Paused
• SceneState (sub-state of InGame)
  • Loading (default)
  • Loaded

Project Layout

src/
  main.rs                 # App bootstrap + plugin wiring
  states.rs               # App/Game/Scene state machines
  engine/
    mod.rs                # Core plugin group
    input/                # Input mapping and input systems
    physics/              # Point-mass, spring, joint, collision logic
    renderer/             # Debug/visual rendering systems and components
    scene/                # Runtime scene creation and teardown
    editor/               # Editor scene, UI, and editor-specific input
  main_menu/
    mod.rs                # Main menu UI and transitions
assets/
  fonts/
  shaders/
  shapes/

Development Notes

• The scene setup currently uses test_scene_setup_system in src/engine/scene/scene_systems.rs.
• Spring constants and friction coefficients are currently hard-coded and can be tuned in scene/physics systems.
• Serialization support modules exist under engine/scene, and can be expanded for save/load workflows.

Roadmap

• Implement a scene save/load workflow, ideally leveraging Bevy's built-in scene tooling (if any).
• Build a proper renderer with support for curves, images, and colors.
• Standardize physics material systems (Friction, Mass, etc...)
• Complete the level editor.
• Add a full sound system.
• Add an options menu for controller, video, and gameplay configuration.

License

This project is dual-licensed under either of the following, at your option:

• MIT License (see LICENSE-MIT)
• Apache License, Version 2.0 (see LICENSE-APACHE)