Ancient Brain
Code. Play. Teach. Learn. Research. Demo.

Starter Tutorial (Three.js)

A tutorial to show you how to code JavaScript Worlds on Ancient Brain using the Three.js graphics library. We will code a simple JavaScript 3D World.
  • The Three.js library is more suitable for programmers with a little experience.
  • Beginners may prefer to start with the P5 Starter Tutorial.
  • In any case, this tutorial will not assume you have ever seen Ancient Brain, JavaScript, or even programming, before.
  • All links from this page open in a new tab/window, to keep this tutorial on screen.

Getting set up

Get an account

  1. To create Worlds, you need an account.
  2. Use "Register" in the menu at the top of the page.
  3. Register, and get your password via email.
  4. Login.

Clone "One Cube World"

  1. Go to the page for "One Cube World" (Three.js version).
  2. This is a simple Starter World. It is less than 30 lines of program code.
  3. It displays a single cube on screen. You can drag and scroll the camera to move and zoom.
  4. Click "Clone" to make your own copy.
  5. Go to the World page for your clone.
  6. Check your clone runs.

One Cube World (...
By Starter user  
Simple starter World (Three.js version). Cube of random color. Built-in camera control.

Edit World

On the World page for your clone, click "Edit" to launch the editor.
  1. Edit the title.
  2. Edit the description.
  3. Go back to the World page and reload. You will see the new title and description.


First look at the code

The editor shows the JavaScript code. If you have never seen JavaScript (or any program) before, here is what you are looking at:
  1. The program is a set of instructions for the computer to "execute".
  2. This is real JavaScript code. You can write in here anything that can be written in JavaScript.
  3. Instructions end with ";". This is important.
  4. Whitespace does not matter. You can add or remove whitespace according to taste.
  5. Comments begin with "//" (and continue to end of line). These are notes to the human reader and are ignored by the computer.

There is a lot to learn about JavaScript but you do not need to learn it all before trying some programming.


Change some code

You can change code, press "Save" and then "Run" the new code. Nothing bad can happen. You cannot damage your machine or our server.

Change the following:

  1. Change the sky color. Here is a list of color names.

  2. Change the object size.

  3. Change the start position of the camera.

  4. The shape is defined as a box of three equal dimensions: ( objectsize, objectsize, objectsize ). That is, a cube. Change the shape to something other than a cube by changing one of the dimensions.
Every time you make a change, press Save, and Run again.

Program structure

This World uses an Ancient Brain structure to define what code runs once at startup, and what code runs every timestep while the World is running. These programs have the following structure:
function World() 		 
{  // Start of World definition 

  this.newRun = function() 
	// Instructions to be executed once, at start of run 

  this.nextStep = function() 
	// Instructions to be executed every time step 
}  // End of World definition					 

Note the chain brackets. These define the start and end of blocks of code.

In the World so far, we did not define any "nextStep" because we did not have any code to execute on every step.

We will now add some new code at certain locations within the structure.

Paint the cube

The cube is "painted" with a random color each time we run the World. It would be nice to paint it with a JPEG or PNG image.

Insert the following code inside "newRun". (Remember the program structure above.)

 const texturefile  = "/uploads/starter/earth.1.jpg";
 var   loader       = new THREE.TextureLoader();
 loader.load ( texturefile, function ( thetexture ) 
 // this defines a function to be called whenever the file is loaded 
        thetexture.minFilter  = THREE.LinearFilter;
        theobject.material    = new THREE.MeshBasicMaterial ( { map: thetexture } );
You will now get something like the following:

Upload your own image

  1. Web search for some image you want to use. Right-click and "Copy image".
  2. Go to menu "User" - "My uploads".
  3. Paste (Ctrl-V) and the image is uploaded.
  4. You can also select an image from your computer by browsing files.
  5. Edit the JavaScript code to point to the image. You need the exact file name of the image.
  6. Change:
    to point to your userid and your file:
  7. The cube will now be painted with your image.

Use other people's uploads

In the header above, in the search box select "Uploads" to see what other people have uploaded. You can use all their uploads in your World.

Make the object move

We want the object to move on every time step. So we must now define "nextStep".

Insert the following code inside the World definition, but outside "newRun". (Remember the program structure above.)

this.nextStep = function()
    theobject.position.x = theobject.position.x + AB.randomIntAtoB ( -30, 30 );        

Change the movement

  1. The above code makes a random move in the x dimension on each step.
  2. Change the code to make larger or smaller moves.
  3. Change the code to move smoothly in one direction.

  4. Change the code to make moves in 3 dimensions using:

Add music

Now we add some background music. Insert the following code outside the World definition. (Remember the program structure above.)

 const MUSICFILE = '/uploads/starter/SuspenseStrings.mp3';
 AB.backgroundMusic ( MUSICFILE );

On some browsers (Chrome, mobile) audio will not play automatically, but only in response to user interaction. So the code gives the user play and pause buttons.

See notes on audio autoplay on web browsers and in particular on Chrome.

Use your own music

  1. Get some music you like.
  2. One site with free music is There are many others.
  3. When you find music you like, download the music file to your computer.
  4. Then upload the music file to Ancient Brain.
  5. Edit the code to play your music file.


  1. Errors while writing programs are normal. The important thing is to understand where the error is.
  2. The editor warns you about errors using an X icon on the left-hand side. Hover on it for info.
  3. When you save the file, you will be warned again in the pop-up.
  4. Some errors cannot be detected in the editor and you will only find out when you run the program.
  5. Errors found when the program is run are displayed in the JavaScript console. To see the console, press Ctrl-Shift-J on Chrome and Firefox, or F12 on Edge and IE.



See the "Docs" menu for all the documentation you need when coding.

You can also select code and press "Intelligent code help" to get help on a specific function / object / word.

AB, ABRun and API

Ancient Brain defines a number of support objects and support functions. You may have noticed AB.randomIntAtoB and AB.backgroundMusic above.

  • AB is an Ancient Brain system object. See the AB docs.

  • ABRun is another Ancient Brain object to define a particular run. See the ABRun docs.

You may also have noticed ABWorld.init3d and ABWorld.scene in the original code.

  • ABWorld is defined by the particular API we are using. See the docs for this API.


Clone and edit other Three.js Worlds

Clone other Starter Worlds and change them.

Many of them have a section of code called a "tweaker's box" at the top. This contains the easiest parts of code to change.

For example, Blank Three.js World is quite simple to edit. It has multiple sphere objects, stored in a structure called an Array.

When you get more advanced, you will make your own entire Worlds. The Worlds you create are only limited by your imagination.

Blank Three.js World
By Starter user  
A simple starter World. An Array of spheres. Painted with textures. Random motion.


Show it off

  1. The system will generate an image to represent your World. To change it, see "New image" on the World page.
  2. The site works on mobile. Show off your World to people on your mobile. For some Worlds, touch will automatically drag and zoom the World's camera.
  3. People can find your World using the search box. So give it a good name.
  4. You can embed your World on another website. See "Embed code" on the World page.
  5. Comment on other people's Worlds. The top menu turns red when you have a new comment.

The background is a program, showing the JavaScript graphics used on this site.

© Ancient Brain Ltd. 2018-19. All rights reserved.

Ancient Brain ™ is a trademark of Ancient Brain Ltd.

Platforms      Bug bounty      Contact

Stats      The name      Terms and conditions

Classes in Dublin      Call for partners