public
Created

A CodePen by Tristan. Lightrays v2 - Added some colour. Update: Added colour shift for sun-rise/set.

  • Download Gist
script.js
JavaScript
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124
var canvas, c, w, h,
twoPI = Math.PI * 2,
mX, mY,
resize = true,
mousemove = true,
per = { x: 0, y: 0 },
mtn, trackmouse = false;
 
window.onload = function(){
canvas = document.createElement('canvas')
w = canvas.width = window.innerWidth - 40;
h = canvas.height = window.innerHeight - 40;
c = canvas.getContext('2d');
document.body.appendChild(canvas);
!resize || window.addEventListener('resize', function(e){ w = canvas.width = window.innerWidth - 40; h = canvas.height = window.innerHeight - 40; });
!mousemove || canvas.addEventListener('mousemove', function(e){
trackmouse = true;
mX = e.pageX-20; mY = e.pageY-20;
per = { x: mX, y: mY };
});
mX = w/2;
mY = w/2;
per = { x: w/2, y: h/2, step: 1 }
mtn = new Mountains(300,"10");
window.setInterval(animate,17);
}
function newGradient(gradient){
var grad;
switch(gradient.type){
case "radial":
grad = c.createRadialGradient(gradient.x1, gradient.y1, gradient.r1, gradient.x1, gradient.y1, gradient.r2);
break;
case "linear":
grad = c.createLinearGradient(gradient.x1, gradient.y1, gradient.x2, gradient.y2);
break;
}
for(var i = 0; i < gradient.stops.length; i++){
grad.addColorStop(gradient.stops[i].s, gradient.stops[i].c);
}
return grad;
}
 
function animate(){
if(!trackmouse){
per.x = mX = w/2 + Math.round(Math.cos(per.step)*w/2);
per.y = mY = h/2 + Math.round(Math.sin(per.step)*h/2);
per.step += 0.03;
if(per.step > twoPI)
per.step = 0;
}
c.save();
c.globalCompositeOperation = "source-over";
c.fillStyle = newGradient(
{
type: "radial",
x1: mX,
y1: mY,
r1: 0,
r2: w,
stops: [
{ s: 0, c: "rgba("+ (h-mY) +","+ (h-mY) +","+ (h-mY) +",0.5)" },
{ s: 0.05, c: "rgba("+ (h-mY) +","+ (h-mY-128) +",128,0.5)" },
{ s: 1, c: "rgba(0,"+ (h-mY-128) +","+ (h-mY) +",0.5)" }
]
}
);
c.fillRect(0,0,w,h);
mtn.draw();
}
 
function Mountains(peaks,seed){
var points = [];
this.init = function(){
var step = w / peaks,
y = 0;
points.push({x: 0, y: y});
for(var i = 1; i <= peaks; i++){
y = y + (Math.random() * 20)-10;
points.push({x: i * step, y: y});
}
};
this.draw = function(){
c.save();
//c.fillStyle = "rgba(20,20,20,1)";
c.fillStyle = newGradient({type:"linear", x1: 0, y1: 0, x2: 0, y2: h, stops: [{s:1, c:"rgba(0,0,0,1)"},{s:0, c:"rgba(80,80,80,1)"}]});
c.beginPath();
c.moveTo(points[0].x, h/2-points[0].y);
for(var p = 1; p < points.length; p++){
c.lineTo(points[p].x, h/2 - points[p].y);
}
c.lineTo(w,h);
c.lineTo(0,h);
c.closePath();
c.fill();
c.restore();
c.globalCompositeOperation = "lighter";
c.fillStyle = "rgba("+(h-mY)+","+(h-mY)+","+(h-mY)+",0.03)";
for(var p = 0; p < points.length-1; p++){
var va1 = Math.atan2(h/2-points[p].y - per.y, points[p].x - per.x),
va2 = Math.atan2(h/2-points[p+1].y - per.y, points[p+1].x - per.x);
c.beginPath();
c.moveTo(points[p ].x, h/2-points[p].y);
c.lineTo(points[p+1].x, h/2-points[p+1].y);
c.lineTo(points[p+1].x + Math.cos(va2)*w, h/2-points[p+1].y + Math.sin(va2)*w);
c.lineTo(points[p ].x + Math.cos(va1)*w, h/2-points[p].y + Math.sin(va1)*w);
c.closePath();
c.fill();
}
};
this.init();
}
style.css
CSS
1 2 3
*{margin:0;padding:0;-moz-box-sizing:border-box;-webkit-box-sizing:border-box}
body{font-size:75%;background:#222;font-family:arial;padding:20px 0 0 20px}
canvas{border:1px solid #181818;display:block;box-shadow:0 0 10px #111;background:rgba(20,20,20,1)}

Please sign in to comment on this gist.

Something went wrong with that request. Please try again.