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---
category: tool
tool: p5
contributors:
- ['Amey Bhavsar', 'https://github.com/ameybhavsar24']
- ['Claudio Busatto', 'https://github.com/cjcbusatto']
filename: p5.js
---
p5.js is a JavaScript library that starts with the original goal of [Processing](https://processing.org), to make coding accessible for artists, designers, educators, and beginners, and reinterprets this for today's web.
Since p5 is a JavaScript library, you should learn [Javascript](https://learnxinyminutes.com/docs/javascript/) first.
To run p5.js code, you can go to [the online editor](https://editor.p5js.org/).
```js
///////////////////////////////////
// p5.js has two important functions to work with.
function setup() {
// the setup function gets executed just once when the window is loaded
}
function draw() {
// the draw function gets called every single frame
// if the framerate is set to 30, it would get called 30 times every second
}
// the following code explains all features
function setup() {
createCanvas(640, 480); // creates a new canvas element with 640px as width as 480px as height
background(128); // sets the background color to rgb(128, 128, 128)
// background('#aaf') // you can use hex codes and color names too
}
function draw() {
background('#f2f2fc'); // usually, you call `background` in draw to clear the screen
// creates an ellipse at 10px from the top and 10px from the left, with width and height 37
ellipse(10, 10, 37, 37);
// remember in p5.js the origin is at the top-left corner of the canvas
if (mouseIsPressed) {
// mouseIsPressed is a boolean variable that is true when the mouse is down, and false otherwise
fill(0); // fill sets the fill color, which will stay until it is changed
} else {
fill(255, 255, 255, 240); // fill(a, b, c, d) sets the fill color to rgba(a, b, c, d)
}
ellipse(mouseX, mouseY, 80, 80);
// mouseX and mouseY are the x and y position of the mouse, respectively
// the above code creates and ellipse under the mouse, and fills it with white or black
// some other 2d primitives (shapes) you can draw:
rect(9, 3, 23, 26); // x, y, width, height
noFill(); // sets the fill color to transparent
triangle(100, 400, 130, 200, 200, 300); // x1, y1, x2, y2, x3, y3
point(100, 300); // create a point at x, y
// there are more, but they are more complex.
}
/** Bouncing balls animation
* You can copy-paste this code into the online editor at
* https://editor.p5js.org/
*/
class Ball {
constructor(x, y, xvel, yvel, radius, col) {
this.position = createVector(x, y); // create a p5.Vector object which stores the x and y
this.velocity = createVector(xvel, yvel); // make a p5.Vector storing the velocity
this.radius = radius;
this.col = col; // p5 already uses the word color, so we use col instead
}
update() {
this.position.add(this.velocity); // you can add vectors with p5.Vector.add(p5.Vector)
if (this.position.x + this.radius > width) {
// flip the direction the ball is going in if it touches the edge
this.velocity.x *= -1;
}
if (this.position.x - this.radius < 0) {
this.velocity.x *= -1;
}
if (this.position.y + this.radius > height) {
this.velocity.y *= -1;
}
if (this.position.y - this.radius < 0) {
this.velocity.y *= -1;
}
}
render() {
// you can figure out what this does by now
fill(this.col);
ellipse(this.position.x, this.position.y, this.radius);
}
}
let numBalls = 23;
let balls = [];
function setup() {
createCanvas(400, 400); // width, height
for (let i = 0; i < numBalls; i++) {
let r = random(255); // random number between 0 and 255
let g = random(255);
let b = random(255);
balls.push(
new Ball(
random(30, width), // x position
random(height), // y position
random(-4, 4), // x velocity
random(-4, 4), // y velocity
random(4, 10), // radius
color(r, g, b) // fill color for the ball
)
);
}
}
function draw() {
background(255);
for (let ball of balls) {
ball.update();
ball.render();
}
}
// So far, we have only seen the default rendering mode.
// This time, we will use the 'webgl' renderer
function setup() {
createCanvas(400, 400, WEBGL); // width, height, rendering mode
}
function draw() {
background(0);
stroke('#000');
fill('#aaf');
// rotate around the x, y, and z axes by the frame count divided by 50
rotateX(frameCount / 50);
rotateY(frameCount / 50);
rotateZ(frameCount / 50);
// frameCount is a p5.js variable that stores the amount of frames that have passed
box(50, 50, 50); // width, height, depth
}
```
## Further Reading
- [p5.js | get started](http://p5js.org/get-started/) The official documentation
- [Code! Programming for Beginners with p5.js - YouTube](https://www.youtube.com/watch?v=yPWkPOfnGsw&vl=en) Introduction and Coding challenges using Processing and p5.js by Coding Train
- [The Coding Train](https://codingtra.in/) A website with sketches made in p5 and processing
## Source
- [p5's source code](https://github.com/processing/p5.js)
- [p5.sound.js source](https://github.com/processing/p5.js-sound)
|
