🚀 artoolkit5-wasm

A high-performance WebAssembly (WASM) port of WebARKitLib, utilizing a modified and improved version of ARToolKit5 tailored for modern JavaScript and TypeScript environments. 🎯 This package delivers fast, modular, and memory-optimized marker tracking, pose estimation, and marker generation directly in the web browser or Node.js.

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📦 Installation

Install the package via npm:

npm install @ar-js-org/artoolkit5-wasm

🔗 Peer Dependencies

This library relies on @ar-js-org/artoolkit5-constants for shared ARToolKit constant values. Ensure it is installed in your project:

npm install @ar-js-org/artoolkit5-constants

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🛠️ Usage & API Reference

1. ⚙️ Initialization

Initialize the WebAssembly runtime using the createARToolKit factory. You can optionally configure paths for loading the .wasm binary:

import { createARToolKit } from '@ar-js-org/artoolkit5-wasm';

const { mod, core, constants } = await createARToolKit({
  locateFile: (path, prefix) => `node_modules/@ar-js-org/artoolkit5-wasm/dist/${path}`,
  quiet: false // Set to true to suppress initialization logs
});

• mod: The raw Emscripten module.
• core: The initialized ARToolKitCore instance.
• constants: An object containing essential marker detection constants.

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2. 📁 URL Loaders

ARToolKit requires camera calibration parameters (.dat) and marker pattern (.hiro / custom) files. Utility helpers fetch these binaries and load them directly into the Emscripten Virtual File System (mod.FS):

import { loadCameraFromUrl, addMarkerFromUrl } from '@ar-js-org/artoolkit5-wasm';

// Load camera calibration file
await loadCameraFromUrl(mod, core, 'path/to/camera_para.dat', '/data/camera_para.dat');

// Load pattern marker file
const pattId = await addMarkerFromUrl(mod, core, 'path/to/patt.hiro', '/data/patt.hiro');

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3. 📹 Video Frame Processing & Tracking

Pass video frame data to the WebAssembly module and detect markers inside your frame loop (e.g. requestAnimationFrame):

// Initialize camera tracker dimensions
core.setup(width, height, cameraID);

function processFrame(videoElementData, videoLumaData) {
  // Pass video frames as Uint8Array/typed arrays
  core.passVideoData(videoElementData, videoLumaData, true);

  // Run marker detection
  const numDetected = core.detectMarker();
  if (numDetected > 0) {
    const markerNum = core.getMarkerNum();
    
    for (let i = 0; i < markerNum; i++) {
      const markerInfo = core.getMarkerInfo(i);
      
      // Calculate pose matrix (places calculation result in a shared C++ memory address)
      const markerWidth = 80; // physical width of marker in millimeters
      core.getTransMatSquare(i, markerWidth);

      // Access the 3x4 pose matrix directly from WASM heap to avoid copying overhead
      const ptr = core.getTransform();
      const poseMatrix = mod.HEAPF64.subarray(ptr >> 3, (ptr >> 3) + 12);
      
      console.log(`Detected Marker ID: ${markerInfo.id}`);
      console.log("3x4 Transform Matrix:", poseMatrix);
    }
  }
}

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💻 Development & Building

📋 Prerequisites

To build the project from source, you need:

• Node.js (v22.x or later)
• Docker (to compile the C++ source via Emscripten)
• Git (for submodule management)

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🔨 Compilation Instructions

First, clone the repository recursively to fetch the nested submodules:

git clone --recursive https://github.com/ar-js-org/artoolkit5-wasm.git
cd artoolkit5-wasm
npm install

1. Compile C++ to WebAssembly 🐳

Compiles the C++ source using Emscripten running inside a Docker container:

npm run build:wasm

2. Build TypeScript Wrapper 📦

Bundles the JS/TS wrappers using Vite and compiles the declarations:

npm run build:wrap

3. Build All 🚀

Performs both C++ WebAssembly and JS/TS wrapper builds:

npm run build

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🔍 Code Quality & Linting

Validate C++ code formatting using clang-format:

# Run lint check
npm run lint:cpp

# Automatically format C++ code
npm run format:cpp

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🌐 Examples

Check out the included interactive examples in the examples/ directory:

1. examples/smoke.html: A simple, raw WebAssembly initialization and basic marker addition test.
2. examples/webcam.html: A complete real-time camera tracking example showing how to detect pattern markers, compute pose matrices, and output them to the page without flooding the console.

To run the examples locally, start a static file server:

npx vite

Then navigate to http://localhost:5173/examples/webcam.html in your web browser.

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📄 License

This library is licensed under the MIT License.