Rapier Physics for Flutter

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A high-performance physics engine for Flutter, powered by Rapier. This plugin provides cross-platform support for 3D physics simulation using Rust and WebAssembly.

Features

• Cross-Platform: Support for Android, iOS, macOS, and Web.
• High Performance: Core physics simulation written in Rust.
• Flexible Physics: Support for various rigid body types (Dynamic, Fixed, Kinematic).
• Force & Impulse: Full support for addForce, applyImpulse, and their AtPoint variants.
• Velocity Control: Set linear and angular velocities directly for precise state control.
• Colliders: Box, Sphere, Cylinder, Capsule, Cone, and Heightfield colliders.
• Joints Support: Fixed, Spherical, Revolute, Prismatic, and Rope joints with motor support.
• Lifecycle Management: Robust API for adding and removing rigid bodies, colliders, and joints with automatic relationship cleanup.
• CCD: Continuous Collision Detection for high-speed simulation.
• Modern Web Support: Efficient WASM implementation using dart:js_interop.

Getting Started

Setup

Choose one of the following methods to set up the native libraries:

1. Use Prebuilt Library

If you prefer not to build from source, you can use the prebuilt binaries provided in the repository.

2. Build by Yourself

To build the library from source, follow these steps:

Install Cargo

• 2-1. curl https://sh.rustup.rs -sSf | sh
• 2-2. source $HOME/.cargo/env
• 2-3. cargo --version

Build Library

• 2-4. cd native/rapier_ffi
• 2-5. ./build.sh

This script will:

• Compile .so files for Android and place them in android/src/main/jniLibs.
• Compile .a files for iOS/macOS and create a .xcframework.
• Compile .wasm for the Web and place it in the example project.

2. Basic Usage

Initialize the RapierWorld and start simulating:

import 'package:rapier_physics/rapier_physics.dart';

void main() async {
  // 1. Initialize the world (asynchronous for WASM support)
  final world = RapierWorld();
  await world.init();

  // 2. Add a static floor
  world.addBox(
    x: 0, y: 0, z: 0, 
    hx: 10.0, hy: 0.1, hz: 10.0, 
    type: RigidBodyType.fixed
  );

  // 3. Add a dynamic falling box
  final box = world.addBox(
    x: 0, y: 10, z: 0, 
    hx: 0.5, hy: 0.5, hz: 0.5
  );

  // 4. Step the simulation in your game loop
  Timer.periodic(Duration(milliseconds: 16), (timer) {
    world.step();
    print('Box Position: ${box.position}');
  });
}

Supported Rigid Body Types

• RigidBodyType.dynamic: Fully simulated by physics.
• RigidBodyType.fixed: Static object, does not move.
• RigidBodyType.kinematicPositionBased: Moved by setting position.
• RigidBodyType.kinematicVelocityBased: Moved by setting velocity.

Project Structure

• lib/: Dart source code and bindings logic.
• native/rapier_ffi/: Rust source code for the physics bridge.
• example/: Flutter example application.

License

This project is licensed under the MIT License.