Function intersect

docs/app/js/sanddance-app.js:102199–102217

(a, b, edge, bbox, out = [])

    return result;
}
function intersect(a, b, edge, bbox, out = []) {
    let t;
    let snap;
    if (edge & 8) {
        t = (bbox[3] - a[1]) / (b[1] - a[1]);
        snap = 3;
    } else if (edge & 4) {
        t = (bbox[1] - a[1]) / (b[1] - a[1]);
        snap = 1;
    } else if (edge & 2) {
        t = (bbox[2] - a[0]) / (b[0] - a[0]);
        snap = 2;
    } else if (edge & 1) {
        t = (bbox[0] - a[0]) / (b[0] - a[0]);
        snap = 0;
    } else return null;
    for(let i = 0; i < a.length; i++)out[i] = (snap & 1) === i ? bbox[snap] : t * (b[i] - a[i]) + a[i];
    return out;
}
function bitCode(p, bbox) {
    let code = 0;
    if (p[0] < bbox[0]) code |= 1;