A slightly updated version of syntagmatic’s Canvas Random Motion with some convoluted mouse attraction and destruction
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Little Black Hole
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<!DOCTYPE html> | |
<meta charset="utf-8"> | |
<canvas id="canvas"></canvas> | |
<script src="http://d3js.org/d3.v3.min.js"></script> | |
<script> | |
var num = 10000; | |
var canvas = document.getElementById("canvas"); | |
var width = canvas.width = 960; | |
var height = canvas.height = 500; | |
var ctx = canvas.getContext("2d"); | |
var CoG = null; | |
var rad = 20; | |
var particles = d3.range(num).map(function(i) { | |
return [Math.round(width*Math.random()), Math.round(height*Math.random())]; | |
}); | |
d3.select("canvas").on("mouseout",CofGravityGone).on("mousemove",CofGravity) | |
d3.timer(step); | |
d3.timer(function(){ctx.fillStile}) | |
function CofGravityGone(e){ | |
CoG = null; | |
} | |
function CofGravity(e){ | |
CoG = d3.mouse(this); | |
} | |
function sign(x) { return x > 1 ? 1 : x < -1 ? -1 : 0; } | |
function moveit(p) { | |
var rand = Math.random(); | |
var dx=p[0] - CoG[0]; | |
var dy=p[1] - CoG[1]; | |
var dist = Math.sqrt(dx*dx+dy*dy); | |
if (dist > rad || Math.random() < 0.7){ | |
if (rand*2 < Math.abs(dx)/(Math.abs(dx)+Math.abs(dy))){p[0] += sign(CoG[0]-p[0]);} | |
else if (rand >0.5 && rand <=0.75) {p[0] += Math.round(2*Math.random()-1);} | |
else if (rand >0.75){p[1] += Math.round(2*Math.random()-1);} | |
else{p[1] += sign(CoG[1]-p[1]);} | |
} | |
else { | |
if (rand*2 < Math.abs(dx)/(Math.abs(dx)+Math.abs(dy))){p[0] += -sign(CoG[0]-p[0])*rad+Math.random()*rad;} | |
else if (rand >0.5) { | |
p[0] = Math.round(width*Math.random()); | |
p[1] = Math.round(height*Math.random()); | |
} | |
else{p[1] += -sign(CoG[1]-p[1])*rad+Math.random()*rad;} | |
} | |
return p; | |
} | |
function step() { | |
ctx.fillStyle = "rgba(0,0,0,0.2)"; | |
ctx.fillRect(0,0,width,height); | |
ctx.fillStyle = "rgba(193,107,240,1)"; | |
particles.forEach(function(p, i) { | |
if (i == Math.round(num/4)) ctx.fillStyle = "rgba(71,100,226,1)"; | |
if (i == Math.round(num/2)) ctx.fillStyle = "rgba(255,255,255,1)"; | |
if (i == Math.round((num/4)*3)) ctx.fillStyle = "rgba(142,43,46,1)"; | |
if (CoG != null) { | |
p = moveit(p); | |
} | |
else { | |
p[0] += Math.round(2*Math.random()-1); | |
p[1] += Math.round(2*Math.random()-1); | |
} | |
if (p[0] < 0) p[0] = width; | |
if (p[0] > width) p[0] = 0; | |
if (p[1] < 0) p[1] = height; | |
if (p[1] > height) p[1] = 0; | |
drawPoint(p); | |
}); | |
}; | |
function drawPoint(p) { | |
ctx.fillRect(p[0],p[1],1,1); | |
}; | |
</script> | |
<style> | |
html, body { margin: 0; padding: 0; } | |
</style> |
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