File size: 3,650 Bytes
c0adbf1
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
let w, h;
const ctx = canvas.getContext("2d");
const { sin, cos, PI, hypot, min, max } = Math;

function spawn() {
    
    const pts = many(333, () => {
        return {
            x: rnd(innerWidth),
            y: rnd(innerHeight),
            len: 0,
            r: 0
        };
    });
    
    const pts2 = many(9, (i) => {
        return {
            x: cos((i / 9) * PI * 2),
            y: sin((i / 9) * PI * 2)
        };
    });
    
    let seed = rnd(100)
    let tx = rnd(innerWidth); 
    let ty = rnd(innerHeight);
    let x = rnd(innerWidth)
    let y = rnd(innerHeight)
    let kx = rnd(0.8, 0.8)
    let ky = rnd(0.8, 0.8)
    let walkRadius = pt(rnd(50,50), rnd(50,50))
   let r = innerWidth / rnd(100, 150);
    
    function paintPt(pt){
        pts2.forEach((pt2) => {
            if (!pt.len )
                return
            drawLine(
                lerp(x + pt2.x * r, pt.x, pt.len * pt.len),
                lerp(y + pt2.y * r, pt.y, pt.len * pt.len),
                x + pt2.x * r,
                y + pt2.y * r
            );
        });
        drawCircle(pt.x, pt.y, pt.r);
    }
  
    return {
        follow(x,y) {
            tx = x;
            ty = y;
        },
        
        tick(t) {
        
    const selfMoveX = cos(t*kx+seed)*walkRadius.x;
    const selfMoveY = sin(t*ky+seed)*walkRadius.y;
    let fx = tx + selfMoveX;         
    let fy = ty + selfMoveY; 
            
    x += min(innerWidth/100, (fx - x)/10)
    y += min(innerWidth/100, (fy - y)/10)
            
    let i = 0
    pts.forEach((pt) => {
        const dx = pt.x - x,
            dy = pt.y - y;
        const len = hypot(dx, dy);
        let r = min(2, innerWidth / len / 5);
        pt.t = 0;
        const increasing = len < innerWidth / 10 
            && (i++) < 8;
        let dir = increasing ? 0.1 : -0.1;
        if (increasing) {
            r *= 1.5;
        }
        pt.r = r;
        pt.len = max(0, min(pt.len + dir, 1));
        paintPt(pt)
    });               
        } 
    }
}

const spiders = many(2, spawn)

addEventListener("pointermove", (e) => {
    spiders.forEach(spider => {
        spider.follow(e.clientX, e.clientY)
    })
});
requestAnimationFrame(function anim(t) {
    if (w !== innerWidth) w = canvas.width = innerWidth;
    if (h !== innerHeight) h = canvas.height = innerHeight;
    ctx.fillStyle = "#000";
    drawCircle(0, 0, w * 10);
    ctx.fillStyle = ctx.strokeStyle = "#fff";
    t/=1000
    spiders.forEach(spider => spider.tick(t))
    requestAnimationFrame(anim);
});

function recalc(X, Y) {
    tx = X;
    ty = Y;
}

function rnd(x = 1, dx = 0) {
    return Math.random() * x + dx;
}

function drawCircle(x, y, r, color) {
    ctx.beginPath();
    ctx.ellipse(x, y, r, r, 0, 0, PI * 2);
    ctx.fill();
}

function drawLine(x0, y0, x1, y1) {
    ctx.beginPath();
    ctx.moveTo(x0, y0);

    many(100, (i) => {
        i = (i + 1) / 100;
        let x = lerp(x0, x1, i);
        let y = lerp(y0, y1, i);
        let k = noise(x/5+x0, y/5+y0) * 2;
        ctx.lineTo(x + k, y + k);
    });

    ctx.stroke();
}

function many(n, f) {
    return [...Array(n)].map((_, i) => f(i));
}

function lerp(a, b, t) {
    return a + (b - a) * t;
}

function noise(x, y, t = 101) {
    let w0 = sin(0.3 * x + 1.4 * t + 2.0 + 
                 2.5 * sin(0.4 * y + -1.3 * t + 1.0));
    let w1 = sin(0.2 * y + 1.5 * t + 2.8 + 
                 2.3 * sin(0.5 * x + -1.2 * t + 0.5));
    return w0 + w1;
}

function pt(x,y){
    return {x,y}
}