Ancient Brain
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P5 Starter Tutorial

A tutorial to show you how to code JavaScript Worlds on Ancient Brain using the "P5" graphics library.



  1. To create Worlds, you need an account.
  2. Use the following link to register. (Link opens in a new tab.)
  3. Register, and get your password via email.
  4. Login.
Register
  
  

  1. We will use "One Cube World" as a simple Starter World.
  2. Click the image to run it.
  3. This World displays a single cube on screen.
  4. You cannot move the camera so the cube rotates to show you it is 3D.


One Cube World (P5)
438 runs ♦ 0 likes
By Starter user  
Created: 10 Nov 2018
Modified: 3 Sep 2019
Simple starter World (P5 version). No camera control. So cube rotates to show 3D.
  
  

  1. Use the link below to go to the "home page" for the Starter World. (Link opens in a new tab.)
  2. Now you are logged in, you can click "Clone" to make your own copy.
  3. Go to the page for your clone.
  4. Check your clone runs.
Starter 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.

  
  

The editor shows the JavaScript code:
 
 
const objectsize    = 200;      // size of object   

const anglechange   = 0.01;     // how much the rotate angle changes each step 

var angle = 0;                  // rotate angle starts at 0  


function setup()        // "setup" is called once at start of run 
{
  createCanvas ( ABWorld.fullwidth(), ABWorld.fullheight(),  WEBGL );
}

function draw()         // "draw" is called every timestep during run 
{
    background("lightblue");    // background color 
    fill("navy");               // paint box with this color 
           
    rotateX(angle);             // set each dimension rotation angle to "angle"
    rotateY(angle);
    rotateZ(angle);
  
    box(objectsize);            // draw a cube of this size 
  
    angle = angle + anglechange ;       // change angle each step to get rotate movement        
}

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. You can insert blank lines, spaces and tabs in order to change the program layout and normally it does not matter. The program will still work the same.
  5. You can insert "comments". These begin with "//" and continue to the 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.

 
 
 
 

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 object size.

  2. Change how much the rotation angle changes each step. Changing this can make a dramatic difference.

  3. Change the background color. Here is a list of color names.

  4. Change the cube color.

  5. You can change the box to not be a cube by giving it numbers for all 3 dimensions:
     box ( width, height, depth ); 
    For example:
     box ( 200, 50, 1000 ); 
    
Every time you make a change, press Save, and Run again.



P5 programs use the following structure to define what code runs once at startup, and what code runs every time step:

// Can define global variables and constants up here, outside both functions  

function setup() 		 
{
	// Instructions to be executed once, at start of run 
} 

function draw()
{
	// Instructions to be executed every time step 
}  

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

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




The cube is "painted" with a solid color. It would be nice to paint it with a JPEG or PNG image.

Insert the following code at the top of the program:

var img;

function preload() 
{
   img = loadImage (  "/uploads/starter/earth.1.jpg" );
}

Put the following code inside the "draw" function. Remove the line that makes the cube a solid color, and insert this line instead:

texture(img);        	

You will now get something like the following:





  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:
     /uploads/starter/earth.1.jpg 
    to point to your userid and your file:
     /uploads/your-userid/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.
 
 
 

Change the line
  box(objectsize); 
to the following:
 box(objectsize); 
 translate(250, 250, 250);
 box(objectsize); 

This makes a second box some distance away. Both will rotate.




To see the power of programming, we will make lots of boxes, using what is called a for loop.

Insert the following code at the top:

// make an array of random (x,y,z) positions 

const noboxes = 30;                 	// how many boxes to have 
var a = new Array(noboxes);         	// array of the box positions

for ( var i=0; i < noboxes; i++ )   	// set up the array
{
    a[i] = [ AB.randomIntAtoB(-500,500), AB.randomIntAtoB(-500,500), AB.randomIntAtoB(-500,500) ];
}	

Insert the following code inside "draw", replacing the previous "box" and "translate" instructions:

for ( var i=0; i < noboxes; i++ )
{
  translate ( a[i][0], a[i][1], a[i][2] );		// get box position i 
  box(objectsize);             
}

This makes a large number of boxes in randomly different places, like the following image. Increase the number of boxes until your browser cannot cope. Don't worry, you cannot cause any damage!





Now we add some background music. Insert the following code right at the top:
 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 dl-sounds.com. 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.


There are more ways of getting help:

 
 
 
 

Clone other Starter Worlds and change them. See:

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

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


Tutorial 18.7
259 runs ♦ 0 likes
By "Coding Train" p...  
Created: 9 Sep 2018
Modified: 11 Sep 2018
Tutorial 18.7 with full canvas, resized model, sound. Texture on box is image from another user.
Tutorial 7.8 variant
169 runs ♦ 0 likes
By "Coding Train" p...  
Created: 6 Sep 2018
Modified: 11 Sep 2018
Tutorial 7.8 with music and other uploaded images, including from other users. Click on the images.
 
 
 

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.