From 507c5f6e382def58f5ab76456d74fb3a3179a6d5 Mon Sep 17 00:00:00 2001
From: Asif Bacchus <asif@bacchus.cloud>
Date: Wed, 8 Apr 2020 04:08:51 -0600
Subject: [PATCH] basic animation as per tutorial

---
 js/particles.js | 142 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 142 insertions(+)

diff --git a/js/particles.js b/js/particles.js
index e69de29..130ffbe 100644
--- a/js/particles.js
+++ b/js/particles.js
@@ -0,0 +1,142 @@
+/* create particles animation
+    based on the amazing tutorial by 'Franks Labratory'
+    https://youtu.be/d620nV6bp0A
+*/
+
+const canvas = document.getElementById('canvas1');
+const canvasContext = canvas.getContext('2d');
+canvas.width = window.innerWidth;
+canvas.height = window.innerHeight;
+
+let particlesArray;
+
+// get mouse position
+let mousePosition ={
+    x: null,
+    y: null,
+    radius: (canvas.height / 80) * (canvas.width / 80)
+};
+
+// add mouse position event listener
+window.addEventListener('mousemove', function(event){
+    mousePosition.x = event.x;
+    mousePosition.y = event.y;
+});
+
+// create particle class
+class Particle{
+    constructor(x, y, directionX, directionY, size, colour) {
+        this.x = x;
+        this.y = y;
+        this.directionX = directionX;
+        this.directionY = directionY;
+        this.size = size;
+        this.colour = colour;
+    }
+    // method to draw individual particles
+    draw(){
+        canvasContext.beginPath();
+        canvasContext.arc(this.x, this.y, this.size, 0, Math.PI * 2, false);
+        canvasContext.fillStyle = '#8c5523';
+        canvasContext.fill();
+    }
+    // check particle position, mouse position, move particle and draw it
+    update(){
+        // check if particle is still within canvas
+        if (this.x > canvas.width || this.x < 0){
+            this.directionX = -this.directionX;
+        }
+        if (this.y > canvas.height || this.y < 0){
+            this.directionY = -this.directionY;
+        }
+
+        // collision detection between mouse and particles
+        let dx = mousePosition.x - this.x;
+        let dy = mousePosition.y - this.y;
+        let distance = Math.sqrt((dx * dx) + (dy * dy));
+        if (distance < mousePosition.radius + this.size){
+            if (mousePosition.x < this.x && this.x < canvas.width - this.size * 10){
+                this.x += 10;
+            }
+            if (mousePosition.x > this.x && this.x > this.size * 10){
+                this.x -= 10;
+            }
+            if (mousePosition.y < this.y && this.y < canvas.height - this.size * 10){
+                this.y += 10;
+            }
+            if (mousePosition.y > this.y && this.y > this.size * 10){
+                this.y -= 10;
+            }
+        }
+
+        // move particle
+        this.x += this.directionX;
+        this.y += this.directionY;
+
+        // draw particle
+        this.draw();
+    }
+}
+
+// create particle array
+function init(){
+    particlesArray = [];
+    let numberOfParticles = (canvas.height * canvas.width) / 9000;
+    for (let i = 0; i < numberOfParticles * 2; i++){
+        let size = (Math.random() * 5) + 1;
+        let x = (Math.random() * ((innerWidth - size * 2) - (size * 2)) + size * 2);
+        let y = (Math.random() * ((innerHeight - size * 2) - (size * 2)) + size * 2);
+        let directionX = (Math.random() * 5) - 2.5;
+        let directionY = (Math.random() * 5) - 2.5;
+        let colour = '#8c5523';
+
+        particlesArray.push(new Particle(x, y, directionX, directionY, size, colour));
+    }
+}
+
+// check if particles are close enough to connect to eachother
+function connect(){
+    let opacityValue = 1;
+    for (let a = 0; a < particlesArray.length; a++){
+        for (let b = a; b < particlesArray.length; b++){
+            let distance = ((particlesArray[a].x - particlesArray[b].x) * (particlesArray[a].x - particlesArray[b].x)) + ((particlesArray[a].y - particlesArray[b].y) * (particlesArray[a].y - particlesArray[b].y));
+            if (distance < (canvas.width / 7) * (canvas.height / 7)){
+                opacityValue = 1 - (distance / 20000);
+                canvasContext.strokeStyle = `rgba(140, 85, 31, ${opacityValue})`;
+                canvasContext.lineWidth = 1;
+                canvasContext.beginPath();
+                canvasContext.moveTo(particlesArray[a].x, particlesArray[a].y);
+                canvasContext.lineTo(particlesArray[b].x, particlesArray[b].y);
+                canvasContext.stroke();
+            }
+        }
+    }
+}
+
+// animation loop
+function animate(){
+    requestAnimationFrame(animate);
+    canvasContext.clearRect(0, 0, innerWidth, innerHeight);
+
+    for (let i = 0; i < particlesArray.length; i++){
+        particlesArray[i].update();
+    }
+    connect();
+}
+
+// resize event
+window.addEventListener('resize', function(){
+    canvas.width = innerWidth;
+    canvas.height = innerHeight;
+    mousePosition.radius = ((canvas.height / 80) * (canvas.width / 80));
+    init();
+});
+
+// mouse-out event (mouse leaving the window)
+window.addEventListener('mouseout', function(){
+    mousePosition.x = undefined;
+    mousePosition.y = undefined;
+});
+
+init();
+animate();