RTX - Ray Tracer

A ray tracer written in C++17 that renders 3D scenes described via a configuration file. Outputs images in PPM format.

Features

• Primitives: Sphere, Plane, Cone, Torus
• Lighting: Ambient, diffuse (Lambert), point lights, directional lights, shadow casting
• Anti-aliasing: 30 samples per pixel with random jitter
• Camera: Configurable position, field of view, and resolution
• Implicit surfaces: Cone and Torus solved via algebraic equation solvers (quadratic, quartic)
• Scene config: Declarative .cfg files via libconfig++

Dependencies

• C++17 compiler (clang++ recommended)
• libconfig++

On macOS:

brew install libconfig

On Ubuntu/Debian:

sudo apt-get install libconfig++-dev

Build

make

This produces the rtx executable.

make clean   # Remove object files
make fclean  # Remove object files and binary
make re      # Full rebuild

Usage

./rtx <scene_file.cfg> > output.ppm

Example:

./rtx config.cfg > render.ppm

The image is written to stdout in PPM format. Redirect it to a file and open it with any image viewer that supports PPM (e.g., GIMP, Preview on macOS, feh on Linux).

Scene Configuration

Scenes are described in libconfig format.

Camera

camera:
{
    resolution = {width = 1920; height = 1080;};
    position   = {x = -1.0; y = 0.0; z = 10.0;};
    rotation   = {x = 0.0; y = 0.0; z = 0.0;};
    fieldOfView = 60.0; # degrees
};

Primitives

primitives:
{
    spheres = (
        {x = 0.0; y = 0.0; z = -1.2; r = 0.5; color = {r = 199; g = 21; b = 133;};}
    );

    planes = (
        {
            position = {x = 0.0; y = -2.0; z = 0.0;};
            vector   = {x = 0.0; y = 1.0;  z = 0.0;}; # normal
            color    = {r = 152; g = 251; b = 152;};
        }
    );

    cones = (
        {x = 2.0; y = 3.0; z = -3.0; r = 3.0; h = 5.0; color = {r = 180; g = 180; b = 180;};}
    );

    tori = (
        {
            center       = {x = -1.0; y = 0.0; z = 1.5;};
            major_radius = 1.0;
            minor_radius = 0.65;
            color        = {r = 200; g = 50; b = 200;};
        }
    );
};

Lights

lights:
{
    ambient = 0.2;
    diffuse = 0.8;

    point = (
        {x = 5.0; y = 5.0; z = 5.0; intensity = 1.0;}
    );

    directional = (
        {x = 0.0; y = -1.0; z = 0.0; intensity = 0.3;}
    );
};

Project Structure

RTX/
├── Makefile
├── config.cfg          # Example scene
├── include/            # Header files
│   ├── Camera.hpp
│   ├── Color.hpp
│   ├── Cone.hpp
│   ├── HitRecord.hpp
│   ├── Image.hpp
│   ├── Light.hpp
│   ├── Lights.hpp
│   ├── Material.hpp
│   ├── Object.hpp
│   ├── Plane.hpp
│   ├── Point3D.hpp
│   ├── Ray.hpp
│   ├── RayTracer.hpp
│   ├── Rectangle3D.hpp
│   ├── Setup.hpp
│   ├── Sphere.hpp
│   ├── Torus.hpp
│   └── Vector3D.hpp
└── src/
    ├── Main.cpp
    ├── Camera/
    ├── Color/
    ├── Image/
    ├── Math/           # Polynomial solvers (cubic, quartic)
    ├── Point3D/
    ├── Ray/
    ├── RayTracer/
    ├── Rectangle3D/
    ├── Setup/
    ├── Shapes/         # Sphere, Plane, Cone, Torus
    └── Vector3D/

Architecture

Component	Role
Object	Abstract base class for all scene primitives
RayTracer	Core rendering loop with shadow and shading logic
Setup	Parses .cfg file and builds scene objects
Camera	Generates primary rays from a viewpoint
Image	Pixel buffer; writes PPM to stdout
poly34	Algebraic solvers for cone/torus intersections