JS_Projects/fourierSeries/drawing.js

let res = 5;
const pi = Math.PI;
const p = 2;
class Drawing {
    constructor(xoffset, yoffset, scale, num) {
        this.t = 0;
        this.n = num;
        this.x = [0];
        this.y = [0];
        this.a = [0];
        this.r = [0];
        this.xoffset = xoffset;
        this.yoffset = yoffset;
        this.scale = scale;
        this.poslog = [];
        this.fc = 0;
        this.refresh();
        this.setPos();
    }

    refresh() {
        this.t = 0;
        this.x[0] = 0;
        this.y[0] = 0;
        for (let i = 0; i < this.n; i++) {
            this.x[i + 1] = this.x[i];
            this.y[i + 1] = this.y[i];
            this.a[i] = 0;
            this.r[i] = random(0.5, 3.5);
        }
        this.x = this.x.slice(0, this.n - 1);
        this.y = this.y.slice(0, this.n - 1);
        this.poslog = [];
        this.setPos();
    }

    update() {
        this.t += 1 / 144;
        
        for (let i = 0; i < this.n; i++) {
            let m = i * 2 + 1;
            this.a[i] = sin(m * this.t);
            this.r[i] = 4/(m*pi);
        }this.setPos();

        if (this.poslog.length >= 1) {
            if (Math.abs(this.x[this.n - 1] - this.poslog[this.poslog.length - 1].x) > 5) {
                this.logPos();
            }
        } else
            this.logPos();
    }

    fx(x, n) {
        let a = 0;
        if (n % 2 == 0) {
            let b = 0;
        } else {
            let b = (4) / (n * pi);
        }
        let result = 0;
        let l = pi;
        for (let i = 1; i <= n; i++) {
            result += sin((2*i-1)*x)/(2*i-1);
        }
        return result;
    }

    show() {
        this.fc++;

        push();
        translate(this.xoffset / 2, this.yoffset);

        strokeWeight(10 * this.scale);
        point(0, 0);

        strokeWeight(10 * this.scale);
        for (let i = 0; i < this.n; i++) {
            point(this.x[i], this.y[i]);
        }

        strokeWeight(4 * this.scale);
        line(0, 0, this.x[0], this.y[0]);
        for (let i = 1; i < this.n; i++) {
            line(this.x[i - 1], this.y[i - 1], this.x[i], this.y[i]);
        }

        pop();
        this.showTrail();
    }

    setPos() {
        this.x[0] = cos(this.a[0]*2*pi) * this.r[0] * 100 * this.scale;
        this.y[0] = sin(this.a[0]*2*pi) * this.r[0] * 100 * this.scale;
        for (let i = 1; i < this.n; i++) {
            this.x[i] = this.x[i - 1] + cos(this.a[i]) * this.r[i] * 100 * this.scale;
            this.y[i] = this.y[i - 1] + sin(this.a[i]) * this.r[i] * 100 * this.scale;
        }
    }

    logPos() {
        if (this.poslog.length < 144 / this.scale * 10) {
            //this.poslog.push(createVector(this.t, this.y[this.n - 1]));
            this.poslog.push(createVector(this.t, 100 * this.fx(map(this.t, 0, p*pi, -pi, pi), 101)));
        } else {
            this.poslog.shift();
            //this.poslog.push(createVector(this.t, this.y[this.n - 1]));
            this.poslog.push(createVector(this.t, 100 * this.fx(map(this.t, 0, p*pi, -pi, pi), 101)));
        }
    }

    showTrail() {
        push();
        translate(this.xoffset / 2, this.yoffset);
        strokeWeight(3 * this.scale);
        stroke(33);
        noFill();
        line(this.scale * 500, this.scale * 500, this.scale * 500, -this.scale * 500);
        beginShape();
        for (let i = 0; i < this.poslog.length; i++) {
            vertex(-this.poslog[i].x * 50 + this.t * 50 + this.scale * 500, this.poslog[i].y);
        }
        endShape();
        pop();
    }
}