miniRT

miniRT is a simple yet powerful ray tracing engine designed for rendering 3D scenes with realistic lighting, shadows, and reflections. It is built as part of the common core of 42 London.

Table of Contents

• Features
• Installation
• Usage
• Scene Description File
• Define Scene with Codes
• Controls
• Useful Links

Features

• Interactive: Supports moving objects and lights on the fly.
• Basic Primitives: Supports spheres, planes, and cylinders.
• Lighting: Includes ambient, directional, and point lights.
• Shadows.
• Reflections: Supports reflective surfaces.
• Configurable Camera: Customizable camera position and orientation.
• Color: RGB colors and customizable checkerboard color for spheres.

Installation

Ubuntu and X window are required. To install miniRT, :

1. Clone the repository:

   git clone https://github.com/theVeryPulse/miniRT.git

2. Navigate to the project directory:

   cd miniRT

3. Build the project:

   make

Usage

Once compiled, you can use the miniRT executable to render 3D scenes.

Basic Command

./miniRT [scene_file.rt]

• scene_file.rt: Path to the scene description file (in .rt format).

Example

./miniRT demo/room.rt

Scene Description File

The scene file is a text file that describes the 3D scene to be rendered. Here's a simple example:

A  0.3                                       255,255,255
C  0,0,0            0,0,1    70
L  -10,1,-10                 0.9             255,255,255
sp 0,0,-20                   4               255,0,0
pl 0,-10,0          0,1,0                    0,100,100
cy 5.0,0.0,-20.6    1,0,0    10.2    2.42    10,0,255

• A: Ambient light (intensity, color)
• C: Camera (position, angle, field of view)
• L: Point light (position, intensity, color)
• sp: Sphere (position, radius, color)
• pl: Plane (position, normal vector, color)
• cy: Cylinder (position of center, axis, diameter, height, color)

Coordinate convention: right-hand coordinates: x-axis points to the right of screen, y-axis points to the up of screen, z-axis points outwards the screen.

Camera angle vector: points to the viewer rather than the scene.

Multiple point lights are supported. In order to define multiple point lights, use l instead of L. Example

A  0.3                                       255,255,255
C  0,0,0            0,0,1    70
l  -10,1,-10                 0.9             255,255,255
l  0,-10.5                   0.3             255,255,255
sp 0,0,-20                   4               255,0,0
pl 0,-10,0          0,1,0                    0,100,100
cy 5.0,0.0,-20.6    1,0,0    10.2    2.42    10,0,255

Note: Colored lights are NOT supported but parameters are required as part of the format.

Define Scene with Codes

More options on reflectivity, specular exponent, checkerboard colored sphere are supported only by editing the code directly. Check load_scene_from_code.c for example.

Controls

miniRT supports some interaction functions. After a scene is rendered, you can use tab to switch between objects and lights and change their position.

Key(s)	Action
← →	Move object along x-axis (left/right)
↑ ↓	Move object along y-axis (up/down)
i o	Move object along z-axis (for/back -ward)
[ ]	Increase/decrease fov
tab	Switch between objects and lights
Esc	Exit the program

Useful Links

Computer Graphics from Scratch - Gabriel Gambetta - a straightforward and quick guidance to start rendering shapes

Scratchpixel - A more comprehensive guidance where many conventions are discussed.