Implementing a Virtual Fitting Room with Three.js and TypeScript

To create a virtual fitting room that overlays 3D models on a live camera feed, you'll need to combine several technologies including Three.js for 3D rendering, camera access via WebRTC, and potentially some form of pose detection.

Here's a general approach to implementing this:

1. Setting up the basic structure

First, create a TypeScript project with Three.js:

TYPESCRIPTCopied
import * as THREE from 'three';
import { OrbitControls } from 'three/examples/jsm/controls/OrbitControls';
import { GLTFLoader } from 'three/examples/jsm/loaders/GLTFLoader';

class VirtualFittingRoom {
  private scene: THREE.Scene;
  private camera: THREE.PerspectiveCamera;
  private renderer: THREE.WebGLRenderer;
  private videoElement: HTMLVideoElement;
  private videoTexture: THREE.VideoTexture | null = null;
  
  constructor(container: HTMLElement) {
    // Initialize Three.js components
    this.scene = new THREE.Scene();
    this.camera = new THREE.PerspectiveCamera(
      75, window.innerWidth / window.innerHeight, 0.1, 1000
    );
    this.renderer = new THREE.WebGLRenderer({ alpha: true });
    this.renderer.setSize(window.innerWidth, window.innerHeight);
    container.appendChild(this.renderer.domElement);
    
    // Create video element for camera feed
    this.videoElement = document.createElement('video');
    this.videoElement.style.position = 'absolute';
    this.videoElement.style.top = '0';
    this.videoElement.style.left = '0';
    this.videoElement.style.width = '100%';
    this.videoElement.style.height = '100%';
    this.videoElement.style.objectFit = 'cover';
    container.appendChild(this.videoElement);
    
    // Set up camera position
    this.camera.position.z = 5;
    
    // Add lights
    const ambientLight = new THREE.AmbientLight(0xffffff, 0.5);
    this.scene.add(ambientLight);
    
    const directionalLight = new THREE.DirectionalLight(0xffffff, 0.8);
    directionalLight.position.set(0, 1, 1);
    this.scene.add(directionalLight);
    
    // Handle window resize
    window.addEventListener('resize', this.onWindowResize.bind(this));
    
    // Start animation loop
    this.animate();
  }
  
  async initCamera(): Promise<void> {
    try {
      const stream = await navigator.mediaDevices.getUserMedia({ video: true });
      this.videoElement.srcObject = stream;
      this.videoElement.play();
      
      // Create video texture
      this.videoTexture = new THREE.VideoTexture(this.videoElement);
      this.videoTexture.minFilter = THREE.LinearFilter;
      this.videoTexture.magFilter = THREE.LinearFilter;
      
      // Optional: Use the video as background
      // this.scene.background = this.videoTexture;
    } catch (error) {
      console.error('Error accessing camera:', error);
    }
  }
  
  loadModel(modelPath: string): void {
    const loader = new GLTFLoader();
    
    loader.load(
      modelPath,
      (gltf) => {
        const model = gltf.scene;
        // Position and scale the model appropriately
        model.position.set(0, 0, 0);
        model.scale.set(1, 1, 1);
        this.scene.add(model);
      },
      (xhr) => {
        console.log(`${(xhr.loaded / xhr.total) * 100}% loaded`);
      },
      (error) => {
        console.error('Error loading model:', error);
      }
    );
  }
  
  private onWindowResize(): void {
    this.camera.aspect = window.innerWidth / window.innerHeight;
    this.camera.updateProjectionMatrix();
    this.renderer.setSize(window.innerWidth, window.innerHeight);
  }
  
  private animate(): void {
    requestAnimationFrame(this.animate.bind(this));
    this.renderer.render(this.scene, this.camera);
  }
}

// Usage
document.addEventListener('DOMContentLoaded', () => {
  const container = document.getElementById('fitting-room-container');
  if (container) {
    const fittingRoom = new VirtualFittingRoom(container);
    fittingRoom.initCamera();
    fittingRoom.loadModel('path/to/clothing-model.glb');
  }
});

2. Implementing body tracking

For a realistic virtual fitting room, you'll need to track the user's body position. You can use libraries like:

• TensorFlow.js with PoseNet or MoveNet
• MediaPipe
• Jeeliz VTO (Virtual Try-On)

Here's a simplified example using TensorFlow.js with PoseNet:

TYPESCRIPTCopied
import * as tf from '@tensorflow/tfjs';
import * as posenet from '@tensorflow-models/posenet';

// Add to your VirtualFittingRoom class:
private poseNetModel: posenet.PoseNet | null = null;

async initPoseDetection(): Promise<void> {
  // Load PoseNet model
  this.poseNetModel = await posenet.load({
    architecture: 'MobileNetV1',
    outputStride: 16,
    inputResolution: { width: 640, height: 480 },
    multiplier: 0.75
  });
  
  // Start pose detection
  this.detectPose();
}

private async detectPose(): Promise<void> {
  if (!this.poseNetModel || !this.videoElement) return;
  
  // Detect poses
  const pose = await this.poseNetModel.estimateSinglePose(this.videoElement);
  
  // Update 3D model position based on pose keypoints
  this.updateModelPosition(pose);
  
  // Continue detection
  requestAnimationFrame(this.detectPose.bind(this));
}

private updateModelPosition(pose: posenet.Pose): void {
  // Get relevant keypoints
  const keypoints = pose.keypoints;
  
  // Example: Find shoulders to position clothing
  const leftShoulder = keypoints.find(kp => kp.part === 'leftShoulder');
  const rightShoulder = keypoints.find(kp => kp.part === 'rightShoulder');
  
  if (leftShoulder && rightShoulder && leftShoulder.score > 0.5 && rightShoulder.score > 0.5) {
    // Find the model in the scene
    const clothingModel = this.scene.getObjectByName('clothing');
    if (clothingModel) {
      // Calculate position based on shoulders
      const shoulderMidX = (leftShoulder.position.x + rightShoulder.position.x) / 2;
      const shoulderMidY = (leftShoulder.position.y + rightShoulder.position.y) / 2;
      
      // Convert from 2D screen coordinates to 3D world coordinates
      // This is a simplified example - you'll need proper coordinate mapping
      const vector = new THREE.Vector3(
        (shoulderMidX / window.innerWidth) * 2 - 1,
        -(shoulderMidY / window.innerHeight) * 2 + 1,
        0
      );
      vector.unproject(this.camera);
      
      // Update model position
      clothingModel.position.set(vector.x, vector.y, vector.z);
      
      // You may also need to adjust rotation and scale
    }
  }
}

3. Advanced features

For a more realistic fitting room, consider:

1. Depth estimation to properly place clothing behind/in front of body parts
2. Cloth simulation for realistic movement
3. Segmentation to handle occlusion between the user and virtual clothing

Resources

• Three.js examples: https://threejs.org/docs/manual/en/introduction/Creating-a-scene.html
• GLTFLoader for loading 3D models: https://threejs.org/docs/examples/en/loaders/GLTFLoader.html
• OrbitControls for camera manipulation: https://threejs.org/docs/examples/en/controls/OrbitControls.html

For more advanced implementations, you might want to look into specialized AR frameworks like:

• AR.js
• 8th Wall
• WebXR

These provide more sophisticated tracking and integration capabilities for augmented reality experiences.

Remember that accurate body tracking and realistic clothing overlay is a complex task that may require significant optimization for web performance.