Real-Time Ray Tracing Engine

A high-performance CPU-based ray tracing engine written in pure C with real-time rendering capabilities, interactive object manipulation, and physically-based materials.

Features

Rendering

• Real-time ray tracing at 30-60 FPS
• BVH acceleration structure for fast intersection testing
• Multi-threaded rendering with OpenMP
• Double-buffered framebuffer
• Configurable resolution (640x480 to 1920x1080)

Geometry

• Sphere primitives with quadratic intersection
• Box/AABB primitives with slab method intersection
• Extensible object interface for custom primitives

Materials

• Lambertian BRDF for diffuse surfaces
• Specular reflection with controllable reflectivity
• Transparency with Fresnel-based refraction
• Snell's law for accurate light bending
• Opacity control (transparent, translucent, opaque)

Lighting

• Point lights with color, intensity, and range
• Inverse square law attenuation
• Hard shadow rays
• Blinn-Phong specular highlights
• Support for multiple light sources

Interactive Features

• Click and drag to move objects
• Scroll wheel for Z-depth adjustment
• Right-click context menu
• Real-time property editing
• Add/remove objects and lights
• Scene save/load (JSON format)

Building

Prerequisites

• CMake 3.16+
• C11 compiler (GCC, Clang, or MSVC)
• SDL2 development libraries

Windows (MSVC)

mkdir build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
cmake --build . --config Release

Linux/macOS

mkdir build && cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
make -j$(nproc)

Controls

Key	Action
1	Add sphere
2	Add box
3	Add light
Delete	Remove selected object
Tab	Toggle UI
F	Toggle FPS display
F11	Toggle fullscreen
Ctrl+S	Save scene
Esc	Deselect / Close menu

Mouse	Action
Left Click	Select object
Left Drag	Move object (XY plane)
Right Click	Context menu
Scroll	Adjust object depth (Z)

Architecture

src/
├── main.c              # Application entry point
├── math/
│   ├── vector.h/c      # Vector operations
├── core/
│   ├── ray.h/c         # Ray structure
├── geometry/
│   ├── object.h/c      # Generic object interface
│   ├── sphere.h/c      # Sphere primitive
│   ├── box.h/c         # Box primitive
│   └── bvh.h/c         # BVH acceleration
├── material/
│   ├── material.h/c    # Material system
├── light/
│   ├── light.h/c       # Point lights
├── scene/
│   ├── camera.h/c      # Camera and ray generation
│   └── scene.h/c       # Scene management
├── render/
│   ├── framebuffer.h/c # Double-buffered pixels
│   └── renderer.h/c    # Ray tracing core
└── ui/
    ├── window.h/c      # SDL2 window
    ├── input.h/c       # Input handling
    └── ui.h/c          # UI overlay

Performance

Scene	Objects	Target FPS
Simple	≤5	60 FPS
Medium	≤10	30 FPS
Complex	>10	15+ FPS

License

MIT License - see LICENSE for details.

Ray-Tracer