This project has been created as part of the 42 curriculum by mqueiros, aaugusto.

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Description

miniRT is a minimal ray tracer written in C, built as part of the 42 school curriculum. It's goal is to render 3D scenes described in .rt configuration files by simulating the physical behavior of light rays: Computing intersections with geometric objects, applying lighting models, and producing a pixel-accurate image displayed in a window.

The renderer supports the following scene elements:

Element	Identifier
Ambient light	A
Camera	C
Point light	L
Sphere	sp
Plane	pl
Cylinder	cy

Lighting is computed with a Phong shading model (ambient + diffuse + specular components) and includes hard shadow casting. The window is interactive: the camera can be moved and rotated in real time using the keyboard.

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Instructions

Dependencies

• A C compiler (clang)
• X11 development libraries (required by MiniLibX)
• make

On Debian/Ubuntu:

sudo apt-get install gcc make libx11-dev libxext-dev

Compilation

Clone the repository and run make at the project root:

git clone git@github.com:allancrabelo/MiniRT.git miniRT
cd miniRT
make

This compiles libft, minilibx, and the project itself, producing the miniRT binary.

Target	Description
make / make all	Build the binary
make clean	Remove object files
make fclean	Remove object files and binary
make re	Full rebuild

Execution

./miniRT <scene_file.rt>

Example using one of the provided evaluation scenes:

./miniRT evaluation_sheets/01_sphere_basic.rt

Scene File Format

Each line in a .rt file describes one scene element. Lines starting with # are comments.

# Ambient light: identifier  brightness  R,G,B
A  0.2  255,255,255

# Camera: identifier  position  orientation_vector  FOV(degrees)
C  0,0,5  0,0,-1  70

# Point light: identifier  position  brightness  R,G,B
L  0,10,5  0.7  255,255,255

# Sphere: identifier  center  diameter  R,G,B
sp  0,0,0  2  255,0,0

# Plane: identifier  point  normal_vector  R,G,B
pl  0,-1,0  0,1,0  100,200,100

# Cylinder: identifier  center  axis_vector  diameter  height  R,G,B
cy  0,0,0  0,1,0  1.5  4  50,150,255

Controls

Key	Action
Arrow keys	Move camera (translate)
W / S	Move camera forward / backward
A / D	Strafe left / right
Numpad 1–9	Jump to preset camera positions
Q	Re-render at full quality
R	Reset camera to initial position
Tab	Toggle on-screen controls help
Escape / close button	Quit

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Resources

Ray Tracing & Computer Graphics

• "The Ray Tracer Challenge" - Jamis Buck - https://pragprog.com/titles/jbtracer/the-ray-tracer-challenge/ Foundational book covering ray–sphere intersection, shading, reflection, and camera models.
• MiniLibX documentation - https://harm-smits.github.io/42docs/libs/minilibx Documentation for the 42-school graphics library used to open windows and write pixels.

AI Usage

AI tools (GitHub Copilot / ChatGPT) were used during development for the following tasks:

• Debugging - Identifying edge cases in ray–cylinder intersection logic (caps, degenerate axes) and shadow-acne artefacts caused by floating-point precision.
• Mathematical derivations - Verifying the quadratic formula expansions for ray–sphere and ray–cylinder intersections, and simplifying vector projection formulas.
• Code review - Suggesting improvements to memory management patterns and spotting potential out-of-bounds accesses in the parser.
• Documentation - Generating Doxygen-style function comments (@brief, @param, @return) as a starting point, subsequently reviewed and corrected by hand.

AI-generated suggestions were always reviewed, tested, and adjusted before being integrated into the codebase. No AI tool was used to produce complete algorithmic solutions without prior understanding.