MiniRT

MiniRT is a minimalist ray tracer written in C. It renders simple 3D scenes composed of spheres, planes, and cylinders while implementing the fundamental concepts of ray tracing, including ray generation, object intersection, lighting, shading, and camera manipulation.

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Overview

This project introduces the core principles of ray tracing:

• Ray Generation – Casting rays from a virtual camera through an image plane into the scene.
• Object Intersection – Detecting intersections between rays and geometric primitives such as spheres, planes, and cylinders.
• Lighting and Shading – Computing pixel colors based on light sources, material properties, surface normals, and shadows.
• Camera Controls – Navigating and rotating the camera within the scene in real time.

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Dependencies

MiniRT relies on the following libraries:

MiniLibX (MLX)

A lightweight graphics library used for:

• Creating application windows
• Handling keyboard events
• Rendering pixels to the screen

libft

A custom utility library providing:

• String manipulation functions
• Memory management utilities
• Linked list implementations
• General helper functions

Math Library (libm)

The standard C math library used for operations such as:

• sqrt()
• pow()
• cos()
• sin()

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Project Structure

.
├── src/
│   ├── main.c
│   ├── render.c
│   ├── camera_*.c
│   ├── op_ray_*.c
│   ├── op_obj_*.c
│   ├── light_shd_*.c
│   ├── parse_*.c
│   ├── vec_*.c
│   ├── matrix_*.c
│   ├── math_utils.c
│   ├── control.c
│   ├── move_cm.c
│   └── test_utils_*.c
│
├── include/
│   ├── minirt.h
│   └── structs.h
│
├── subject/
│   └── subject.pdf
│
└── Makefile

Source Directory (src/)

File(s)	Description
main.c	Program entry point
render.c	Main ray tracing loop
camera_*.c	Camera setup and manipulation
op_ray_*.c	Ray generation and intersection calculations
op_obj_*.c	Object property manipulation
light_shd_*.c	Lighting and shading calculations
parse_*.c	Scene file parsing
vec_*.c, matrix_*.c, math_utils.c	Mathematical operations and utilities
control.c, move_cm.c	Keyboard input and camera movement
test_utils_*.c	Debugging and utility functions

Include Directory (include/)

File	Description
minirt.h	Main header containing declarations and prototypes
structs.h	Definitions of project data structures

Other Files

File	Description
subject/subject.pdf	Project specification
Makefile	Build configuration

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Compilation

Build the project from the root directory:

make

This compiles all source files and generates the executable:

miniRT

Available Make Targets

make clean

Removes object files (.o).

make fclean

Removes object files and the executable.

make re

Performs a full rebuild (fclean followed by make).

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Usage

Run MiniRT with a scene description file:

./miniRT path/to/scene.rt

Example:

./miniRT scenes/example.rt

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Scene File Format (.rt)

A scene file describes the objects, camera, and lighting present in the scene. Each line begins with an identifier that specifies the type of element being defined.

Supported Identifiers

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

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Example Scene

A 0.2 255,255,255
C -50.0,0,20 0,0,1 70
L -40.0,50.0,0.0 0.6 10,0,255

sp 0.0,0.0,20.0 20.0 255,0,0
pl 0.0,0.0,-10.0 0.0,1.0,0.0 0,0,225
cy 50.0,0.0,20.6 0.0,0.0,1.0 14.2 21.42 10,0,255

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Controls

After the scene is rendered, the camera can be controlled using the keyboard.

Movement

Key	Action
W	Move forward
S	Move backward
A	Move left
D	Move right
Q	Move up
E	Move down

Rotation

Key	Action
↑	Look up
↓	Look down
←	Rotate left
→	Rotate right

Exit

Key	Action
ESC	Close the application

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Learning Objectives

This project provides practical experience with:

• Computer graphics fundamentals
• Ray tracing algorithms
• 3D vector and matrix mathematics
• Geometric intersection calculations
• Lighting and shading models
• Event-driven graphics programming
• Scene parsing and data management in C