miniRT

A basic RayTracer using minilibX
project of 42 Paris's common-core

Goals :

• introduct us to the RayTracing algorithms
• to the implementation of mathematics formulas
• step up in terms of parsing and error handling

Tester :

The configuration file had very precise restrictions, which lead me to implement my very first testing automation : invalid_rt_file_tester
It tests :

• invalid configurations (in 198 different ways)
• memory leaks for each of these configurations

Feel free to use it, fork it, and report eventual issues.

Code stats :

Project :

• 1 contributor (solo project)
• 47 C source files, ~6,700 lines total (6,126 C + 586 headers)
• 14 supported shape types, multi-threaded rendering, BVH acceleration
• 19 test scenes, unit test suite, regression tests, CI/CD pipeline

Tester :

• 198 invalid configurations
• Shell : 361 lines

Stack :

Build

make            # Full build (libft + mlx + miniRT executable)
make test       # Run unit tests
make regression # Run regression tests (compare against reference BMPs)
make lint       # Check code style with clang-format
make coverage   # Run tests with coverage reporting
make benchmark  # Performance benchmarking

Usage

./miniRT <scene_file.rt>              # Render scene in window
./miniRT <scene_file.rt> -save        # Render and save as BMP
./miniRT <scene_file.rt> --threads N  # Use N render threads
./miniRT <scene_file.rt> --threads=auto  # Auto-detect thread count

Multiple options can be combined: ./miniRT scene.rt -save --threads 4

Controls

All movement and look keys support continuous hold for smooth motion.

Action	Key	Description
Move forward/back	W / S	Relative to camera facing direction (XZ plane)
Strafe left/right	A / D	Perpendicular to camera facing (XZ plane)
Move up/down	PgUp / PgDn	World Y axis
Look left/right	Left / Right arrows	Hold for continuous yaw rotation
Look up/down	Up / Down arrows	Hold for continuous pitch rotation
Roll camera	, / .	Hold for continuous roll rotation
FOV increase/decrease	Numpad + / -	Adjust field of view (0-180)
Toggle resolution	R	Switch between draft (4x) and full resolution
Window resize	1 / 2 / 3 / 4	Set window scale
Help overlay	H	Toggle on-screen help text
Info/stats overlay	I	Toggle render stats (FPS, resolution)
Next camera	Space	Cycle through scene cameras
Exit	ESC	Close window

Supported Shapes

Basic shapes

ID	Shape	Parameters	Example
sp	Sphere	center, diameter, color	sp 0,0,-5 2.0 255,0,0
pl	Plane	point, normal, color	pl 0,-1,0 0,1,0 200,200,200
sq	Square	center, normal, side, color	sq 0,0,-5 0,0,1 4.0 255,255,0
cy	Cylinder	center, axis, diameter, height, color	cy 0,0,-5 0,1,0 2.0 4.0 0,255,0
tr	Triangle	vertex1, vertex2, vertex3, color	tr -1,0,-3 1,0,-3 0,2,-3 0,0,255

Extended shapes

ID	Shape	Parameters	Example
co	Cone	center, axis, diameter, height, color	co 0,0,-3 0,1,0 2.0 4.0 30,255,30
dk	Disk	center, normal, diameter, color	dk 0,2,-5 0,0,1 4.0 255,255,30
to	Torus	center, axis, major radius, minor radius, color	to 0,5,-8 0,1,0 2.5 0.7 255,30,255
el	Ellipsoid	center, radii (x,y,z), color	el 4,1.5,-3 2.0,1.2,1.2 30,80,255
bx	Box	center, dimensions (w,h,d), color	bx 8,1.5,-3 3,3,3 255,140,0

Quadric surfaces

ID	Shape	Parameters	Example
hy	Hyperboloid	center, axis, radii (a,b,c), height, color	hy -5,2,-4 0,1,0 1.5,2.0,0 6.0 255,80,30
pa	Paraboloid	center, axis, scale, height, color	pa 0,0,-4 0,1,0 0.8 5.0 30,200,255

Composites

ID	Shape	Parameters	Example
csg	CSG operation	op (0=union, 1=intersect, 2=difference), shape_idx_a, shape_idx_b	csg 2 0 1
me	OBJ Mesh	file path, offset, color	me model.obj 0,0,0 200,200,200

Material properties

Material properties can be appended to any shape line as key:value pairs:

Property	Range	Effect
spec:	0–1	Specular highlight intensity
refl:	0–1	Reflectivity (recursive, max depth 4)
trans:	0–1	Transparency
ior:	>0	Index of refraction (used with trans)

Example: sp 0,0,-5 2.0 255,0,0 spec:0.8 refl:0.3

Features

• Multiple light spots (intensity, shadows, ambient light)
• Multiple cameras (cycle with Space)
• Phong/Blinn-Phong specular highlights, reflections, transparency, refraction
• Texture mapping and bump/normal mapping
• Depth of field (aperture simulation)
• Motion blur (temporal sampling)
• Path tracing / global illumination
• Anti-aliasing and gamma correction
• Progressive rendering (8x → 4x → 2x → 1x for interactive preview)
• Constructive Solid Geometry (CSG: union, intersect, difference)
• OBJ mesh loading
• BVH acceleration structure
• Multi-threaded rendering (--threads N or --threads=auto)
• FPS-style camera controls (WASD relative to camera orientation)
• On-screen HUD: help overlay (H) and render stats (I)
• BMP file export with -save flag

Screenshots :

Gallery :

Scenes showcasing enhanced rendering features (specular highlights, soft shadows, reflections, refraction, anti-aliasing, gamma correction).

Cornell Box

Reflections

Glass Spheres

Solar System

Spiral

Mixed Shapes

Scene files are in gallery/. Use make gen_scene to build the procedural scene generator.