« get me outta code hell

chapter9.js - precanon - Homestuck^2: Preceeding Canon - (re)presentation of HS2 stylized upon Prequel
summary refs log tree commit diff
path: root/chapter9.js
blob: a2b5800c8f5f21e022150452cb27c4b28bc2382e (plain)
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
const el = document.getElementById('lights-out');
// const el2 = document.getElementById('close');
const hooHoo = document.getElementById('hoo-hoo');
const body = document.body;
const article = document.querySelector('article');

let tick = false;
function lightsOut() {
    const rect = el.getBoundingClientRect();
    const start = window.scrollY + rect.y;
    const stop = start + rect.height;
    /*
    const rect2 = el2.getBoundingClientRect();
    const start2 = window.scrollY + rect2.y;
    const stop2 = start2 + rect2.height;
    */
    const y = window.scrollY + window.innerHeight;
    let prog;
    if (y < start) {
        prog = 0;
    } else if (y > stop) {
        /*
        if (y < start2) {
            prog = 1;
        } else if (y > stop2) {
            prog = 0;
        } else {
            prog = 1 - (y - start2) / rect2.height;
        }
        */
        prog = 1;
    } else {
        prog = (y - start) / rect.height;
    }
    interpolateStyle(body, 'background-color',    itpColor(prog, 'rgb(0, 0, 0)'));
    interpolateStyle(article, 'background-color', itpColor(prog, 'rgb(30, 30, 30)'));
    interpolateStyle(article, 'color',            itpColor(prog, 'rgb(255, 255, 255)'));
    for (const chat of article.querySelectorAll('.chat')) {
        if (chat === hooHoo) {
            continue;
        }
        interpolateStyle(chat, 'background-color', itpColor(prog, 'rgb(200, 200, 200)'));
        interpolateStyle(chat, 'border-color', itpColor(prog, 'rgb(255, 255, 255)'));
    }
    interpolateStyle(hooHoo, 'background-color', itpColor(prog, 'rgb(20, 20, 20)'));
}

window.addEventListener('scroll', event => {
    if (!tick) {
        requestAnimationFrame(() => {
            lightsOut();
            tick = false;
        });
        tick = true;
    }
});