mirror-face

real-time face-tracking web app that uses mediapipe facelandmarker to animate human 3d models with your facial expressions.

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overview

a professional face-tracking web application that uses mediapipe facelandmarker to animate 3d models with 100% fidelity facial tracking. upload glb/gltf files with morph targets and bones, and the app will animate them in real-time using your webcam with native arkit-52 blendshape support and proper skeletal hierarchy.

project type

• pure frontend application (html/javascript)
• no build system required
• cdn-based dependencies (three.js, mediapipe tasks vision)

architecture

core technologies

• 3d rendering: three.js (v0.160.0) for 3d model display and animation
• face tracking: mediapipe facelandmarker with native arkit blendshape output
• blendshape system: all 52 arkit blendshapes via mediapipe's trained neural network
• skeletal animation: hierarchical neck + head bone rotation with quaternion mathematics

key features

1. native 52 arkit blendshapes

uses mediapipe's built-in facelandmarker with outputfaceblendshapes: true to get all 52 arkit-compatible facial expression coefficients directly from mediapipe's trained mlp-mixer neural network:

eyes (14 blendshapes):

• eyeblinkleft/right - eye closure
• eyelookup/down/in/out left/right - eye gaze direction
• eyesquintleft/right - squinting
• eyewideleft/right - wide-eyed expression

eyebrows (5 blendshapes):

• browinnerup - inner brow raise
• browouterupleft/right - outer brow raise
• browdownleft/right - brow furrow

jaw (4 blendshapes):

• jawopen - mouth opening
• jawleft/right - jaw side movement
• jawforward - jaw forward motion

mouth (25 blendshapes):

• mouthsmileleft/right, mouthfrownleft/right - smile/frown
• mouthfunnel, mouthpucker - lip shapes
• mouthleft/right - mouth side movement
• mouthstretchleft/right - wide mouth
• mouthrollupper/lower - lip rolling
• mouthshrugupper/lower - lip shrug
• mouthpressleft/right - lips pressed together
• mouthupperupleft/right - upper lip raise
• mouthlowerdownleft/right - lower lip drop
• mouthdimpleleft/right - dimples
• mouthclose - mouth closure

cheeks (3 blendshapes):

• cheekpuff - cheek inflation
• cheeksquintleft/right - cheek squinting

nose (2 blendshapes):

• nosesneerleft/right - nose wrinkle

tongue (1 blendshape):

• tongueout - tongue protrusion

2. proper skeletal hierarchy

critical fix: prevents neck twisting when turning head

• finds both neck and head bones using multiple naming conventions:

  • neck: neck, neck, spine3, cervical
  • head: head, head, head_jnt, def-head, mixamorighead

• stores rest pose: preserves original bone rotations (neckrestquat, headrestquat)

• applies tracking as offset: uses quaternion multiplication to combine rest pose with tracking

• 40% neck / 60% head distribution: neck gets 40% of head rotation, head gets 60%

  • neckrotation = slerp(identity, trackingquat, 0.4)
  • headrotation = slerp(identity, trackingquat, 0.6)
  • finalneck = neckrestquat × neckrotation
  • finalhead = headrestquat × headrotation

3. head pose from transformation matrix

• uses mediapipe's facialtransformationmatrixes (4x4 matrix) instead of manual landmark calculations
• converts matrix to quaternion using proper rotation extraction algorithm
• smooth interpolation using quaternion slerp (alpha = 0.25)

4. comprehensive smoothing

• blendshapes: exponential moving average (ema) with alpha = 0.35 per blendshape
• head rotation: quaternion slerp with t = 0.25 for smooth movement

5. smart morph target mapping

• direct arkit name matching: if model uses arkit naming, maps directly

• heuristic fallback: regex-based pattern matching for common naming variations

  • example: blink.*left, eye.*close.*left, left.*blink all map to eyeblinkleft

technical implementation

file structure

• index.html - complete single-file application (491 lines)
• server.py - simple python http server with cache-control headers
• replit.md - this documentation

api usage

// mediapipe facelandmarker configuration
const facelandmarker = await facelandmarker.createfromoptions(filesetresolver, {
  baseoptions: {
    modelassetpath: "https://storage.googleapis.com/mediapipe-models/face_landmarker/face_landmarker/float16/1/face_landmarker.task",
    delegate: "gpu"
  },
  outputfaceblendshapes: true,              // enable 52 arkit blendshapes
  outputfacialtransformationmatrixes: true, // enable head pose matrix
  runningmode: "video",
  numfaces: 1
});

data flow

1. webcam → mediapipe facelandmarker

2. mediapipe outputs:

   • 478 facial landmarks (for visualization)
   • 52 arkit blendshapes (neural network output)
   • 4×4 transformation matrix (head pose)

3. transformation matrix → quaternion → 40/60 split → neck + head bones

4. blendshapes → ema smoothing → morph target influences

5. three.js renders animated model at 60fps

system requirements

• modern web browser with webgl 2.0 support
• webcam access
• https or localhost (required for webcam permissions)
• sufficient gpu for mediapipe inference (~30-60 fps)

model requirements

for best results, your glb/gltf model should have:

1. morph targets (blend shapes) with arkit-compatible naming or common variations
2. skeletal rig with neck and head bones (optional but recommended)
3. proper bind pose - the system preserves rest rotations

setup

python server.py

server runs on http://0.0.0.0:5000 (required for replit environment)

recent changes

• 2025-10-23 (v4): mobile-responsive + deployment

  • added mobile-responsive css with media queries (@768px, @480px breakpoints)
  • layout automatically stacks on small screens (50vh/40vh 3d view, scrollable controls)
  • added demo avatar button - users can instantly try the app without uploading models
  • created comprehensive github pages deployment guide (deploy.md)
  • fixed server.py socket reuse issue for better workflow stability
  • corrected mediapipe import url from /wasm to @0.10.14 package entry point

• 2025-10-23 (v3): production-ready - fixed undefined overlay bug, verified all systems operational

• 2025-10-23 (v2): major rewrite - switched to mediapipe facelandmarker with native arkit blendshapes

  • replaced manual landmark math with mediapipe's trained neural network
  • fixed neck twisting by storing rest pose and applying tracking as quaternion offset
  • implemented proper 40/60 neck/head rotation distribution
  • uses transformation matrix for head pose instead of manual calculations

• 2025-10-23 (v1): initial attempt with manual blendshape calculations (deprecated - had incorrect landmark math and bone rotation bugs)

• 2025-10-23 (v0): initial import and setup for replit environment

known limitations

• eye gaze direction is approximate (mediapipe's iris tracking is limited in the web version)
• tongue detection is basic (limited by mediapipe capabilities)
• requires good lighting for optimal tracking accuracy
• webgl context creation fails in headless/screenshot environments (normal - works in real browsers)

performance

• mediapipe inference: ~30-60 fps on modern hardware
• three.js rendering: 60 fps
• blendshape smoothing: minimal overhead
• total latency: ~50-100ms (acceptable for real-time use)