• 1. Progress
• 2. File Explanation
• 3. Mathematics

3D-Engine

A custom 3D engine made with python and JavaScript

1. Progress

The MVP (minimum viable product) has now been created. This consists of the rendering of a wireframe of a cube, with some buttons to move it around. This code works for the online JavaScript renderer but not for the terminal renderer. This is because I was originally aiming to develop it for the terminal. However, the the terminal does not have good enough graphical detail. As a result, I have switched to an online renderer.

Below, you can see the current work that I have:

(Note that this is still very much a work in progress)

My next steps are to:

• Improve the format of teh data required to draw 3D data, possible reading stl or obj file
• Add rotation
• Add more sophisticated rendering abilities
• Add a better control system

2. File Explanation

Originally, I aimed to develop this for the terminal before realising this was infeasable. Therefore, I switched to a web based renderer using JavaScript. Therefore, some files are not out of date

• Out of date files (from the old terminal renderer)

  • render_terminal.py - renders the graphics onto the terminal
  • maths.py - The maths used, in Python
  • pygame_setup.py - From when I was testing it in pygame

• Current files (for the JavaScript renderer)

  • render_web.py - loads the web page as a web server, for use with github codespaces
  • Everything in templates folder - contains HTML files
  • Everything in static folder - contains static content and JavaScript

3. Mathematics

This 3D engine was originally based on some mathematics which I derived. Below, you can see the main equation, to find where a point should be based on a number of variables:

• l = distance between screen and camera

• z = z position of point to plot

• d = l-z = distance from point to camera

• x = d-l = distance from point to screen

• c = x or y position of camera

• p = x or y position of point

• r = resultant x or y position of point

/ - 1/ d \ \

r = xtan|180 - tan |--------| | + p

\ \|c - p| / /

However, this approach had a number of problems:

• The equation was producing difficult numbers like negative numbers, and it was hard to understand ow to produce nicer numbers
• The equation was complicated, requiring more processing power
• The equation was not completely working

As a result, I did some research, and switched it to the following equation, which solved all these issues:

point_projected = (focal_length*point)/(focal_length+z)

This required some changes in the program's visualisation of the 3D scene - it now considers the object, screen and camera in a slightly different order