RT

A raytracing engine written in C11 with SDL2. Originally created as a final semester group project at WeThinkCode_ (42 school network) in 2016.

The original unmodified codebase is preserved on the archive branch.

Diamond mesh inside a glass box with reflective walls, refractive spheres, and colored lighting.

Features

• Multiple colored light sources with intensity falloff
• Recursive reflections and refractions (configurable depth)
• Glossy, matte, and transparent materials
• Primitive types: sphere, plane, cylinder, cone, disk, hemisphere
• OBJ mesh import with bounding-box culling
• Per-pixel jittered supersampling (antialiasing) via the SUPER scene parameter
• Multithreaded rendering (64x64 pixel chunks, one pthread per chunk)
• Interactive camera controls (translate, rotate, zoom)
• Scene serialization (save/load)
• BMP export

Gallery

All supported primitive types: sphere, hemisphere, cylinder, cone, and disk.

Reflective and refractive spheres in a mirrored room.

Blender's Suzanne OBJ mesh rendered with glass material and colored lights.

Build & Run

Dependencies: GCC, SDL2 (sdl2-config must be in PATH), pthreads, math library.

make          # Build RT executable
make re       # Full rebuild
make clean    # Remove object files
make fclean   # Remove all build artifacts
./RT <scene>  # Render a scene file, e.g. ./RT scenes/showcase_diamond_room

Compiler flags: -Wall -Wextra -Werror -O3 -pthread -std=c11

Scene File Format

Scenes are tab-indented declarative text files. See example scenes in scenes/.

Global Settings

Setting	Description
MAXDEPTH	Maximum recursion depth for reflections/refractions
RENDER	Image resolution as width height
SUPER	Antialiasing samples per pixel (1 = off)

Blocks

Camera

CAMERA
	LOC		x y z
	DIR		x y z
	UP		x y z

Light

LIGHT
	LOC		x y z
	COLOUR		RRGGBB
	INTENSITY	value
	HALF		value

HALF controls the half-distance for light attenuation.

Material

MATERIAL
	NAME		material_name
	DIFFUSE		RRGGBB intensity
	SPECULAR	RRGGBB intensity
	REFLECT		value
	REFRACT		value
	IOR		value

REFLECT and REFRACT range from 0 to 1. IOR is the index of refraction.

Primitive

PRIMITIVE
	TYPE		sphere|plane|cylinder|cone|disk|hemisphere
	LOC		x y z
	DIR		x y z
	NORMAL		x y z
	RADIUS		value
	ANGLE		value
	MATERIAL	material_name

Object (OBJ mesh)

OBJECT
	FILE		path/to/file.obj
	MATERIAL	material_name

Credits

This project was a collaborative effort. The majority of the original code was written by adippena. rojones also contributed significantly to the codebase and assisted me with the majority of my contributions.

Performance optimisations and codebase commenting were done with the assistance of Claude by Anthropic.