Gravity Game - Cloth Simulation

An interactive cloth simulation game using Pygame, where a physically simulated grid can be cut with hand gestures tracked via webcam.

Current Status

Features

• Physics Simulation: Verlet integration for realistic cloth physics
• Hand Tracking: Control cursor with hand gestures via webcam
• Gesture Recognition: Point finger to cut, make fist to push without cutting
• Visual Effects: Tension display through color changes in connections
• Hand Skeleton Overlay: Schematic display of tracked hand
• Controls:
  • ESC - Exit
  • SPACE - Reset grid
  • R - Release all pins (grid falls)

Test Mode

For development, there is a test mode:

• Window instead of fullscreen (1200x800)
• Automatic timeout after 60 seconds
• Activation: TEST_MODE = True in gravity_game.py

Installation

# Create virtual environment
python3 -m venv .venv
source .venv/bin/activate

# Install dependencies
pip install pygame mediapipe opencv-python

Running

python gravity_game.py

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Hand Tracking Features

Supported Gestures

Gesture	Action
Pointing finger	Cut the grid
Fist	Touch/push grid (without cutting)

Technical Implementation

The hand tracking uses:

• MediaPipe by Google for hand landmark detection
• OpenCV for webcam access
• 21 hand landmarks tracked per hand
• Smoothing algorithm for fluid cursor movement

Architecture

gravity_game/
├── gravity_game.py      # Main game
├── hand_tracker.py      # Hand detection module
├── hand_landmarker.task # MediaPipe model (auto-downloaded)
├── start.sh             # Start script
└── README.md            # Documentation

MediaPipe Hand Landmarks

• Key points:
  • WRIST (0): Wrist
  • THUMB_TIP (4): Thumb tip
  • INDEX_FINGER_TIP (8): Index finger tip (used for cursor)
  • MIDDLE_FINGER_TIP (12): Middle finger tip
  • RING_FINGER_TIP (16): Ring finger tip
  • PINKY_TIP (20): Pinky tip

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Configuration

Key settings in gravity_game.py:

# Test mode configuration
TEST_MODE = True              # Window mode for testing
TEST_WINDOW_SIZE = (1200, 800)
TEST_TIMEOUT_SECONDS = 60

# Hand tracking
USE_HAND_TRACKING = True      # Enable/disable hand tracking
SHOW_HAND_OVERLAY = True      # Show hand skeleton overlay
HAND_OVERLAY_ALPHA = 0.25     # Overlay transparency

# Physics
SPACING = 25                  # Grid spacing
GRAVITY = 0.8                 # Gravity strength
STIFFNESS = 5                 # Constraint iterations
FRICTION = 0.99               # Movement friction
CUT_RADIUS = 30               # Cutting radius

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Dependencies

• Python 3.9+
• pygame 2.6+
• mediapipe 0.10+
• opencv-python

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Credits

Original cloth simulation code by Mohsin Ali (@MOHCINALE)

Hand tracking integration and enhancements by @JWestarp.