tudat-wasm

WebAssembly build of the Tudat astrodynamics library, enabling orbital mechanics simulations directly in web browsers and Node.js.

Overview

This repository provides:

• WASM bindings for the Tudat C++ astrodynamics library via Emscripten/Embind
• NPM package (@tudat/tudatpy-wasm) for JavaScript/TypeScript integration
• Interactive demos hosted on GitHub Pages
• Test suite for both Node.js and browser environments

Quick Start

Prerequisites

• CMake 3.20+
• Ninja build system
• Git
• Python 3.x
• Node.js (for testing)

The Emscripten SDK is downloaded automatically during the first build.

Building

# Clone the repository
git clone https://github.com/tudat-team/tudat-wasm.git
cd tudat-wasm

# Build visualization demo (faster)
cmake -P wasm.cmake

# Build full API with tests
cmake -DFULL_BUILD=1 -P wasm.cmake

The build script will:

1. Download and install Emscripten SDK (v3.1.51) if needed
2. Configure the WASM build
3. Compile the WASM modules
4. Deploy to docs/ for GitHub Pages
5. Start a local web server at http://localhost:8832

Manual Build

# Configure
cmake -B build-wasm \
    -DCMAKE_TOOLCHAIN_FILE=cmake_modules/toolchain-emscripten.cmake \
    -DCMAKE_BUILD_TYPE=Release \
    -G Ninja

# Build visualization demo
cmake --build build-wasm --target tudat_wasm_web

# Build full Embind API
cmake --build build-wasm --target tudatpy_wasm

Project Structure

tudat-wasm/
├── cmake_modules/
│   └── toolchain-emscripten.cmake  # Emscripten toolchain
├── cmake/
│   └── patches/
│       └── cspice-wasm.patch       # SPICE library WASM patch
├── docs/                           # GitHub Pages deployment
├── src/
│   └── tudatpy_wasm/              # WASM bindings source
│       ├── npm/                    # NPM package
│       └── [binding modules]
├── tests/
│   └── wasm/                       # Test suite
│       ├── src/                    # C++ tests
│       ├── web/                    # Browser test UI
│       └── test_wasm_*.js          # Node.js tests
├── wasm.cmake                      # Build orchestration script
└── CMakeLists.txt                  # Main build configuration

NPM Package

The @tudat/tudatpy-wasm package provides TypeScript-friendly bindings:

import createTudatModule from '@tudat/tudatpy-wasm';

const tudat = await createTudatModule();

// Access astrodynamics functions
const mu = tudat.constants.GRAVITATIONAL_CONSTANT;

Testing

Node.js Tests

cd tests/wasm
node test_wasm_api.js
node test_wasm_integration.js

Browser Tests

The build script starts a web server automatically. Alternatively:

cd tests/wasm/web
python start_server.py

Then open http://localhost:8832 in your browser.

GitHub Pages

The docs/ directory is deployed to GitHub Pages, providing:

• Interactive orbit visualization demos
• API documentation (TypeDoc)
• Test suite accessible in-browser

Dependencies

• Emscripten SDK: v3.1.51 (auto-downloaded)
• Tudat: Fetched via CMake FetchContent
• Boost: Headers via Emscripten port
• Eigen3: Linear algebra library
• CSpice: Planetary ephemerides (with WASM patch)
• SOFA: Fundamental astronomy standards
• CesiumJS: 3D globe visualization (for demos)

License

This project follows the same license as Tudat. See LICENSE for details.

Links

• Tudat Documentation
• Tudat GitHub
• TudatPy GitHub