Physics Engine

A 2D physics engine written in Python. This project provides a framework for simulating rigid body dynamics, collision detection, and constraints.

Features

• Rigid Body Dynamics: Simulate the motion of rigid bodies under forces like gravity.
• Collision Detection: Broad-phase and narrow-phase collision detection using AABB and SAT (Separating Axis Theorem).
• Constraints and Joints: Support for distance joints, revolute joints, and more. Recent improvements include better initialization and error handling for joints.
• Visualization: Debugging and visualization tools using Pygame.

Installation

1. Clone the repository:

   git clone https://github.com/yourusername/physics-engine.git
   cd physics-engine

2. Install the required dependencies:

   pip install -r requirements.txt

Usage

Running Examples

The project includes several examples to demonstrate the capabilities of the physics engine. To run an example:

python -m examples.simple_falling

Creating a Custom Simulation

Here's a simple example of how to create a custom simulation:

from src.dynamics.world import World
from src.core.body import Body
from src.core.circle import Circle
from src.math.vec2 import Vec2

# Create a world
world = World(gravity=Vec2(0.0, -9.81))

# Create a body with a circular shape
circle = Circle(center=Vec2(0.0, 10.0), radius=1.0)
body = Body(shape=circle, mass=1.0)

# Add the body to the world
world.add_body(body)

# Step the simulation
for _ in range(100):
    world.step()

Project Structure

• src/: Core source code for the physics engine.
  • collision/: Collision detection algorithms.
  • constraints/: Joint and constraint implementations.
  • core/: Core physics classes (e.g., bodies, shapes).
  • debug/: Debugging and visualization tools.
  • dynamics/: Dynamics and world simulation.
  • math/: Mathematical utilities (e.g., vectors, matrices).
• examples/: Example simulations.
• tests/: Unit tests.
• docs/: Documentation.
• tools/: Utility tools for benchmarking, visualization, and scene editing.
  • benchmark.py: Measure the performance of the physics engine.
  • export_svg.py: Export simulation scenes as SVG files.
  • scene_editor.py: Create or edit simulation scenes interactively.

Tools

The tools/ directory contains utility scripts to assist with development, debugging, and visualization:

Benchmarking

To measure the performance of the physics engine, run:

python tools/benchmark.py

This script simulates varying numbers of bodies and constraints and reports the average time per step.

Exporting to SVG

To export a simulation scene as an SVG file, run:

python tools/export_svg.py

This script creates a visual representation of the current state of the simulation, which can be useful for documentation or debugging.

Scene Editor

To interactively create or edit a simulation scene, run:

python tools/scene_editor.py

This script provides a simple interface for adding or removing bodies and joints, making it easier to set up complex simulations.

Contributing

Contributions are welcome! Please open an issue or submit a pull request for any improvements or bug fixes.

License

This project is licensed under the MIT License. See the LICENSE file for details.