Created
December 10, 2018 01:36
-
-
Save ikr7/4cc9066530899e41e6c01fa15c659d34 to your computer and use it in GitHub Desktop.
Synchronization Phenomena
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
<!DOCTYPE html> | |
<html lang="en" dir="ltr"> | |
<head> | |
<meta charset="utf-8"> | |
<title>Boid Simulation</title> | |
<style media="screen"> | |
body { | |
font-family: "Helvetica Neue", Helvetica, Arial, sans-serif; | |
position: relative; | |
background: black; | |
} | |
canvas { | |
/* background: #def; */ | |
} | |
form { | |
position: absolute; | |
top: 1em; | |
left: 1em; | |
} | |
</style> | |
</head> | |
<body> | |
<canvas></canvas> | |
<form> | |
<!-- <input type="button" id="a" value="aiueo"> --> | |
</form> | |
<script> | |
const $ = document.querySelector.bind(document); | |
const width = 960; | |
const height = 500; | |
const canvas = $('canvas'); | |
const context = canvas.getContext('2d'); | |
document.body.style.width = width; | |
document.body.style.height = height; | |
canvas.width = width; | |
canvas.height = height; | |
context.fillStyle = 'white'; | |
context.lineWidth = 3; | |
let N = 128; | |
let pendulums = []; | |
for (let i = 0; i < N; i++) { | |
pendulums[i] = { | |
ang: Math.random() * 2 * Math.PI, | |
angv: 0.025 + 0.0125 * Math.random() | |
}; | |
} | |
function draw () { | |
// context.fillStyle = 'rgba(255, 255, 255, 0.66)'; | |
// context.fillRect(0, 0, width, height); | |
// context.fillStyle = 'rgba(0, 0, 0, 1.0)'; | |
context.clearRect(0, 0, width, height); | |
context.beginPath(); | |
context.arc(width / 2, height / 2, 230, 0, Math.PI * 2, false); | |
context.closePath(); | |
context.strokeStyle = 'white'; | |
context.stroke(); | |
context.strokeStyle = 'black'; | |
pendulums.forEach((p) => { | |
context.beginPath(); | |
context.arc(230 * Math.cos(p.ang) + width / 2, 230 * Math.sin(p.ang) + height / 2, 10, 0, Math.PI * 2, false); | |
context.closePath(); | |
context.fill(); | |
context.stroke(); | |
}); | |
} | |
function step () { | |
const eps = 0.01; | |
let p = []; | |
for (let i = 0; i < N; i++) { | |
let sync = 0; | |
for (let j = 0; j < N; j++) { | |
sync += Math.sin(pendulums[j].ang - pendulums[i].ang); | |
} | |
p[i] = { | |
ang: pendulums[i].ang + pendulums[i].angv + eps * sync / N, | |
angv: pendulums[i].angv | |
}; | |
} | |
pendulums = p; | |
} | |
(function animate () { | |
draw(); | |
step(); | |
setTimeout(animate, 1000 / 30); | |
})(); | |
</script> | |
</body> | |
</html> |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment