This is a 2D rigid body physics engine written in C++ for game development, featuring collision detection, constraint solving, and advanced capabilities like explosions and object slicing.

Tech Stack

• Core: C++ with minimal dependencies
• Rendering: OpenGL 3.3+, GLAD, GLFW
• UI: Dear ImGui
• Serialization: Cereal, RapidJSON
• Build: Visual Studio 2019+ (MSVC)
• Testing: CppUnitTestFramework

Project Structure

Rebuild of cphysics/ ├── include/CPhysics/ # Core physics headers (20 files) ├── src/ # Physics implementation (~1,562 LOC) ├── testbed/ # OpenGL visualization + demos │ ├── Tests/ # 15 physics demonstration scenarios │ └── imgui/ # Dear ImGui integration ├── dependencies/ # Third-party libraries └── UnitTests/ # Unit test suite

Core Components

Physics Engine:

• World.h/cpp - Main simulation container, time-stepping, gravity
• Body.h/cpp - Rigid bodies with mass, velocity, forces, torque
• Shape.h - Abstract base (Circle, Polygon implementations)
• Arbiter.h/cpp - Collision detection and contact resolution
• Joint.h - Constraint system (body-to-body, body-to-point springs)

Collision System:

• Broadphase: AABB overlap testing
• Narrowphase: Circle-circle, circle-polygon, polygon-polygon
• Sequential Impulses solver with friction and restitution
• Contact manifolds (up to 2 contact points)

Advanced Features:

• Slice.h - Cut objects along arbitrary lines
• ParticleExplosion.h, ProximityExplosion.h, RaycastExplosion.h - 3 explosion types
• Shadowcast.h - Visibility/shadow calculations
• Ray.h - Ray casting for queries

Testbed Demos (15 scenarios):

• Chains, Trebuchet, Newton's Cradle
• Friction, Restitution, Drag testing
• Stack, Bouncing ball, Wrecking ball
• All 3 explosion types, Object slicing
• Line of sight, Ray casting

Architecture Highlights

1. Polymorphic shape system - Virtual base class for extensibility
2. Sequential Impulses solver - Iterative constraint resolution
3. Spring-based joints - Configurable stiffness and damping
4. AABB optimization - Broadphase filtering before collision checks
5. Data-driven config - Serializable settings with ImGui controls

Key Features

• Pure C++ implementation (no external physics library)
• Convex polygon support (arbitrary vertex count)
• Stable object stacking
• Momentum conservation
• Static/dynamic friction
• Customizable restitution (bounciness)
• Real-time parameter tuning via GUI
• Save/load settings

The testbed (testbed/Main.cpp) provides an interactive OpenGL window where you can run demos, visualize physics (AABBs, contacts, centers of mass), and tweak solver parameters in real-time.

Screenshots