🚀 Real-Time Ray Tracer (RT)

A high-performance, modular ray tracing engine written in modern C++ with a focus on clean architecture, extensibility, and educational value. This project demonstrates advanced C++ concepts, mathematical foundations, and computer graphics principles.

📋 Table of Contents

• Overview
• Features
• Architecture
• Installation
• Usage
• Technical Details
• Project Structure
• Roadmap
• Contributing
• License

🎯 Overview

This ray tracing engine implements a physically-based rendering system that simulates light transport in 3D environments. The project serves as both a learning platform for computer graphics concepts and a foundation for more advanced rendering applications.

Key Highlights

• Modular Design: Clean separation of concerns with dedicated classes for vectors, rays, colors, and rendering
• Performance Optimized: Efficient mathematical operations and memory management
• Extensible Architecture: Easy to add new features like materials, lighting, and geometric primitives
• Modern C++: Utilizes C++17/20 features for type safety and performance
• Educational Focus: Well-documented codebase perfect for learning ray tracing fundamentals

✨ Features

Current Implementation

• ✅ Vector Mathematics: Complete 3D vector operations (addition, subtraction, multiplication, dot/cross products)
• ✅ Ray Generation: Efficient ray creation and manipulation for camera projection
• ✅ Color Management: RGB color space handling with proper gamma correction
• ✅ Camera System: Pinhole camera model with configurable aspect ratio and resolution
• ✅ Gradient Background: Sky-like gradient rendering based on ray direction
• ✅ PPM Output: Standard PPM image format for easy viewing and processing

Planned Features

• 🔄 Geometric Primitives: Spheres, planes, triangles, and complex meshes
• 🔄 Material System: Diffuse, metallic, dielectric, and custom materials
• 🔄 Lighting: Point lights, area lights, and environment maps
• 🔄 Shadows & Reflections: Realistic shadow casting and surface reflections
• 🔄 Anti-aliasing: Multi-sampling for smooth edges and reduced noise
• 🔄 Acceleration Structures: BVH trees for efficient ray-object intersection
• 🔄 Texture Mapping: UV coordinates and procedural textures
• 🔄 Motion Blur: Temporal effects for dynamic scenes

🏗️ Architecture

Core Components

1. Vec3 Class (Vec3.h, Vec3.cpp)

The mathematical foundation of the engine, providing:

• 3D vector operations with operator overloading
• Efficient memory layout with array-based storage
• Mathematical utilities (length, normalization, dot/cross products)
• Type-safe operations with const-correctness

2. Ray Class (Ray.h)

Represents light rays in 3D space:

• Origin and direction vectors
• Ray parameterization for intersection calculations
• Immutable design for thread safety
• Efficient at(t) method for point evaluation

3. Color System (Color.h, Color.cpp)

Handles color representation and output:

• RGB color space with proper gamma correction
• PPM format output for image generation
• Namespace-based organization for clarity
• Stream-based output for flexibility

4. Main Renderer (main.cpp)

Orchestrates the rendering pipeline:

• Camera setup with configurable parameters
• Ray generation for each pixel
• Viewport and pixel coordinate calculations
• Progress tracking and output management

Design Patterns

• RAII: Automatic resource management
• Const Correctness: Immutable operations where appropriate
• Operator Overloading: Intuitive mathematical syntax
• Namespace Organization: Clear separation of concerns
• Stream-Based I/O: Flexible output handling

🛠️ Installation

Prerequisites

• C++17/20 compatible compiler (GCC 7+, Clang 5+, MSVC 2017+)
• CMake 3.10 or higher
• Make or Ninja build system

Build Instructions

# Clone the repository
git clone <repository-url>
cd RT

# Create build directory
mkdir build && cd build

# Configure with CMake
cmake ..

# Build the project
make -j$(nproc)
# or
ninja

Running the Renderer

# Generate a test image
./RT > output.ppm

# View the result (requires image viewer)
# On Linux: eog output.ppm
# On macOS: open output.ppm
# On Windows: start output.ppm

📖 Usage

Basic Rendering

#include "Color.h"
#include "Ray.h"
#include "Vec3.h"

// The engine automatically generates a gradient sky
// based on ray direction for each pixel

Customizing Parameters

// Modify these parameters in main.cpp for different results
auto aspect_ratio = 16.0 / 9.0;  // Widescreen format
int image_width = 400;           // Resolution
auto focal_length = 1.0;         // Camera distance
auto viewport_height = 2.0;      // Field of view

Output Format

The renderer outputs PPM (Portable Pixmap) format:

• Header: P3 (ASCII RGB)
• Dimensions: width height
• Color depth: 255
• Pixel data: R G B values per line

🔬 Technical Details

Mathematical Foundations

Vector Operations

• Addition/Subtraction: Component-wise operations
• Scalar Multiplication: Efficient scaling with operator overloading
• Dot Product: Used for lighting calculations and projections
• Cross Product: Essential for normal calculations and coordinate systems
• Normalization: Unit vector generation for direction calculations

Ray Tracing Algorithm

1. Camera Setup: Define viewport and pixel grid
2. Ray Generation: Create rays from camera through each pixel
3. Intersection Testing: (Future) Test rays against scene objects
4. Color Calculation: Determine pixel color based on ray direction
5. Output: Write RGB values to image file

Coordinate System

• Right-handed: Standard computer graphics convention
• Y-up: World coordinate system with Y pointing upward
• Camera Space: Z-axis pointing into the scene

Performance Considerations

• Memory Layout: Array-based vector storage for cache efficiency
• Const References: Minimize copying in function parameters
• Inline Functions: Small mathematical operations inlined for speed
• Stream Buffering: Efficient output handling for large images

📁 Project Structure

RT/
├── CMakeLists.txt          # Build configuration
├── main.cpp               # Main rendering loop
├── Vec3.h                 # Vector mathematics interface
├── Vec3.cpp               # Vector mathematics implementation
├── Ray.h                  # Ray class definition
├── Color.h                # Color utilities interface
├── Color.cpp              # Color utilities implementation
└── cmake-build-debug/     # Build artifacts

File Descriptions

• CMakeLists.txt: Modern CMake configuration with proper target setup
• main.cpp: Entry point with camera setup and rendering pipeline
• Vec3.h/cpp: Mathematical foundation with 3D vector operations
• Ray.h: Ray representation for light transport simulation
• Color.h/cpp: Color space handling and image output utilities

🗺️ Roadmap

Phase 1: Foundation (Current) ✅

• Vector mathematics library
• Ray representation and manipulation
• Basic camera system
• Color output system
• Gradient background rendering

Phase 2: Geometric Primitives (Next)

• Sphere intersection algorithms
• Plane and triangle primitives
• Mesh loading and rendering
• Bounding box calculations
• Ray-object intersection testing

Phase 3: Materials and Lighting

• Diffuse material implementation
• Metallic and dielectric materials
• Point and area light sources
• Shadow casting algorithms
• Reflection and refraction

Phase 4: Advanced Features

• Anti-aliasing (multi-sampling)
• Acceleration structures (BVH)
• Texture mapping system
• Motion blur and depth of field
• Environment maps and HDR lighting

Phase 5: Optimization and Polish

• Multi-threading support
• GPU acceleration (CUDA/OpenCL)
• Real-time preview mode
• Scene file format (JSON/YAML)
• GUI for parameter adjustment

Phase 6: Production Features

• Advanced materials (subsurface scattering, anisotropy)
• Volume rendering (fog, smoke, clouds)
• Animation and keyframe support
• Network rendering capabilities
• Plugin system for custom shaders

🤝 Contributing

We welcome contributions! Please see our contributing guidelines:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Development Guidelines

• Follow modern C++ best practices
• Maintain const-correctness and RAII principles
• Add comprehensive unit tests for new features
• Update documentation for API changes
• Ensure cross-platform compatibility

Code Style

• Use meaningful variable and function names
• Include proper header guards and includes
• Follow consistent indentation (4 spaces)
• Add comments for complex algorithms
• Use [[nodiscard]] for important return values

📄 License

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

🙏 Acknowledgments

• Inspired by "Ray Tracing in One Weekend" by Peter Shirley
• Built with modern C++ principles and best practices
• Designed for educational and professional use

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Built with ❤️ and modern C++