miniRT

Minirt- FFORNES- && GMACIAS-

You can read the readme in English by clicking here

Introduction

Minirt is a project that introduces you to the fascinating world of Raytracing. With this project, you will learn to render images generated by computer using basic Raytracing techniques. Discover how realistic images are created from scratch!

Example images

Here are some images render with Minirt :

These images show what you can achieve with the project and give you an idea of ​​how the final results will look!

What is Minirt?

Minirt is a Raytracing project that allows you:

• Render 3D images: Create computer generated images using basic Raytracing techniques.
• Understand key concepts: Learn about the camera, lights, and geometric figures such as circles, plans and cylinders.
• Apply mathematical formulas: it implements formulas for the intersection of rays with different objects.

Continue reading to get more details on how to configure and use Minirt , including how to define the map, intersection formulas, and how to control the camera and keyboard.

Index

1. Introduction
2. Map of elements
   • Map example
   • Elements details
3. Formulas
   • 3D sphere
   • Flat
   • Cylinder
4. Ray intersection
   • Ray and sphere
   • Ray and flat
   • Ray and cylinder
   • Shading
5. Data and camera structure
   • General structure (t_info and t_data)
   • Chamber structure (t_camera)
6. Keyboard
   • Get out of the program
   • Move the camera
   • Rotate the camera
   • Adjust the field of vision (FOV)
7. Medium
   • Key settings
   • Library management
8. Demonstration
   • Initial configuration and scene load
   • Interaction with the camera and rendered in real time

Map of elements

The map defines the elements that will appear in your image. Here we show you how to configure each type of element:

• Chamber : Define the perspective from which you will see the image.
• Environment Light : Control the general lighting on the scene.
• Light : Create a focus of lighting on the scene.
• Figures : You can add circles, plans and cylinders.

Map example

Here are an example of how the elements are defined on the map:

 A    0.3          255,255,255   					(Luz de ambiente: intensidad, color)
C    0,1,-10      0,0,1         70          				(Cámara: posición, vector de dirección, FOV)
L    0,10,-10     0.7           255,255,255 				(Luz: posición, intensidad, color)

pl   0,0,0        0,1,0         100,100,100 				(Plano: posición, vector normal, color)
sp   0,0,0        5             255,0,10   				(Esfera: posición, radio, color)
cy   4,0,0        1,1,0         4            6         10,0,255   	(Cilindro: posición, radio, altura, color)

Elements details

• Camera (c)

  • Position : 0.1, -10 (where the camera is located)
  • Address vector : 0.0,1 (where the camera is looking at)
  • FOV : 70 (field of vision, how much you can see from the camera)

• Environment Light (A)

  • Intensity : 0.3 (How strong is the light of atmosphere)
  • Color : 255,255,255 (color light color in RGB format)

• Light (l)

  • Position : 0.10, -10 (where the light source is located)
  • Intensity : 0.7 (how strong the light is)
  • Color : 255,255,255 (color of light in RGB format)

• Plan (PL)

  • Position : 0.0.0 (where the plane is located)
  • Normal vector : 0.1,0 (the address in which the plane is oriented)
  • Color : 100,100,100 (plane color in RGB format)

• Sphere (sp)

  • Position : 0.0.0 (where the sphere is located)
  • Radio : 5 (sphere size)
  • Color : 255.0,10 (color of the sphere in RGB format)

• Cylinder (Cy)

  • Position : 4.0.0 (where the cylinder is located)
  • Radio : 1 (cylinder size)
  • Height : 6 (cylinder height)
  • Color : 10,0,255 (cylinder color in RGB format)

Formulas

3D sphere

The formula of a 3D sphere is:

[(x - h)^2 + (y - k)^2 + (z - l)^2 = r^2]

Where:

• ((H, K, L)) They are the coordinates of the center of the sphere.
• (R) It is the radius of the sphere.
• ((x, y, z)) are the coordinates of a point on the surface of the sphere.

This formula describes all the points ((x, y, z)) that are at a distance (r) of the center ((h, k, l)).

Image of the sphere:

Flat

A 3D plane is represented as: [ax + by + cz + d = 0] where ((a, b, c)) is the normal vector to the plane and (d) is the distance from the origin.

Plan image:

Cylinder

For a cylinder:

• Axis equation: (x - x_0)^2 + (y - y_0)^2 = r^2)
• Height: The difference in the z coordinate between the lower and upper base.

Cylinder image: cylinder

Ray intersection

To render an image, we draw a ray from the camera through each pixel . Then we check if that intersection lightning with an object in the scene. Here we explain how it is calculated:

1. Ray and sphere

For a sphere:

• Ray: Imagine a line that begins in the camera and extends in a specific direction.
• Intersection: replacing the ray equation in the circle formula gives you the distance throughout the lightning where the intersection occurs.

2. Ray and flat

For a 3D plane:

• Ray: as before, represented as a line.
• Intersection: by replacing the ray equation in the plane formula, you get the distance to the intersection point.

3. Ray and cylinder

For a cylinder:

• Axis equation: Use the cylinder formula and replace the lightning equation to find intersection points.

4. Shadow

Once we find the intersection point, we calculate the final color of the pixel with these steps:

1. Initial color:

   • Start with the color of the object and add the environment of the environment.
   • Formula: Initial color = color of the object light of environment

2. Calculate the light:

   • Trace a line from the point of intersection to the light source.
   • Light intensity: It is based on the angle between the normal vector at the intersection point and the vector from the light to the intersection point.
     • Minor angle = greater light intensity.
   • Intensity percentage: determined by this angle.

3. Shade:

   • Verify if there is an object that blocks the light between the intersection point and the light source.
     • If there is a collision, the intersection point is in shade and receives less light.

4. Final color:

   • It combines the initial color with the intensity of the light to obtain the final color of the pixel.
   • Formula: Final color = initial color + light intensity object color

This results in a more realistic image, adjusting the brightness and color according to how light interacts with objects in the scene.

Data and camera structure

In the project, we use several data structures to handle the scene information and camera configuration. Here we explain how they organize:

1. General structure ( t_info and t_data )

• t_info : This structure keeps information about the amount of each type of element in the scene:

  • ambient_light : Amount of environmental lights.
  • camera : Number of cameras.
  • lights : quantity of lights.
  • planes : Amount of plans.
  • spheres : Number of spheres.
  • cylinders : number of cylinders.

• t_data : This structure contains all the information about the image to be rendered:

  • width and height : Image dimensions (wide and tall).
  • info : t_info structure details the amount of each type of object in the scene.
  • line : Count the processed lines.
  • lights , planes , spheres , cylinders : lists that contain the objects on the scene. These lists store the information of lights, plans, spheres and cylinders, respectively.
  • camera : Information about the camera.
  • ambient_light : Information about environmental light.

2. Chamber structure ( t_camera )

The camera is responsible for defining the perspective from which the image is rendered. Its structure includes:

• fov : The field of vision (FOV) of the camera, which determines how much can be seen from the camera. A greater value means a broader field of vision.
• center : A vector that represents the position of the center of the camera in space.
• euler : A vector that contains the angles of Euler, used to guide the camera in the 3D space.
• q : A quaternion that is used to represent the 3D camera rotation. Quaternions are useful to avoid problems with interpolation and 3D rotation.

Keyboard

In the project, the keyboard keys allow the camera to be controlled and adjust the view of the scene. Here is a detailed explanation of how each key works and why we use certain techniques for camera management.

1. Exit the program

• ESC / Control + C key: Close the window and finish the program.

2. Move the camera

• W keys, A, S, D: They are used to move the camera in different directions:

  • W: move the camera forward (in the direction you are looking at).
  • A: move the camera to the left (perpendicular to the direction of the view).
  • S: move the camera back (opposite to the direction of the view).
  • D: Move the camera to the right (perpendicular to the direction of the view).

  These keys modify the center of the camera, which is the point from which the camera is watching the scene. Moving the center of the camera changes the position of the camera in space without rotating it.

• SPACE key: Elevate the camera up.

• Shift key: lower the camera down.

3. Rotate the camera

• Arrow keys above (UP_K) and below (Down_K): They adjust the vertical inclination of the camera:

  • UP_K: Inclinates the camera up, changing the vertical viewing angle.
  • Down_K: Inclinates the camera down, changing the vertical viewing angle.

• Left arrow keys (Left_k) and right (right_k): They adjust the horizontal rotation of the camera:

  • Left_k: Rote the camera to the left, changing the horizontal viewing angle.
  • Right_k: Rote the camera to the right, changing the horizontal viewing angle.

  These keys modify Euler's angles of the camera, which are the angles that determine how the camera is oriented in space. Euler's angles are used to adjust the inclination and rotation of the camera in a simple way.

Euler angles

4. Adjust the field of vision (FOV)

• Key + (plus_k): increases the camera's field of vision by 5 degrees, up to a maximum of 180 degrees.
• Key - (minus_k): Decreases the camera's field of vision by 5 degrees, up to a minimum of 0 degrees.

Medium

This project is designed to be compatible with both Linux and Macos , and specific configurations have been implemented to ensure that it works without problems in both operating systems.

Key settings

In the projects that handle graphics and entries of the user, such as keys, it is common for the codes associated with each key to vary according to the operating system. To handle these differences:

• A configuration file is defined where a specific value is assigned to each relevant key, such as the keys to move the camera or adjust the view.
• This file assigns the correct codes for each key depending on whether it is being executed in Linux or Macos.

For example:

• The ESC key is used to get out of the program.
• The W, A, D keys, D allow the camera to be moved in the corresponding addresses.
• The arrow keys are used to rotate the camera on the vertical and horizontal axis.
• The + and - Adjust the camera (FOV) field of vision.
• The space key moves the camera up and the Shift key moves it down.

Library management

The project uses Minilibx (MLX) , which is a light library for 2D graphics programming, specially designed for UNIX environments such as Linux and Macos. However, due to the differences between the operating systems, it is necessary to properly configure the libraries and the routes of these so that the project is compile correctly in both systems.

1. Detection of the operating system :

   • A variable is used that automatically identifies if the project is running in a Linux or macOS environment.

2. Library configuration :

   • In Linux :
     • The specific MLX library for Linux, which manages the creation of windows, keyboard events, and drawn on the screen is included.
     • In addition, other system libraries such as X11 (which manages graphic interaction in UNIX environments), XEXT (an extension of X11), and math.h (for mathematical functions necessary in graphics) are linked.
   • In macOS :
     • The mlx version compatible with macOS is used.
     • Instead of X11 and Xext libraries used in Linux, Apple's own frameworks are used as OpenGL (for 2D and 3D graphics) and APPKIT (for the graphical interface).

3. Adaptive compilation :

   • Depending on the operating system detected, the makefile adjusts the compilation routes and options automatically. This ensures that the project compile and link all the necessary units correctly, regardless of whether you are in Linux or macOS.

This approach ensures that the project is not only portable between different operating systems, but also remains optimized and compatible with the particularities of each environment.

Demonstration

To illustrate how the project works in practice, we have prepared a series of videos that show different aspects and functionalities of the program in Action. These videos cover:

1. Initial configuration and scene load:

Color.mp4

Movement.mp4

Resolution.mp4

2. Interaction with the camera and rendered real time:

The videos are x4 at a resolution of 800x400

Show1.mp4

Show2.mp4

These clips will provide you with a clear vision of how to use the program and what you can expect in terms of performance and visualization.

How to contribute

If you want to contribute to the project:

1. Fork the repository.
2. Create a branch for your changes.
3. Make the necessary changes .
4. Send a Pull request describing the changes made.

Maybe you may be interested!

- Github FFORNES PROFILE-

HERE

- GMACIAS GMACIAS PROFILE-

HERE

Contacts

◦ Email FFORNES-: [email protected]

◦ Email gmacias-: [email protected]