function loadJavaScript(path) {
    const script = document.createElement("script");
    script.src = path;
    document.head.appendChild(script);
}

function playdemos(list, delay = 10) {
    let fps = frameRate();
    fps = 60;
    let n = floor((frameCount / (delay * fps)) % list.length);
    let func = list[n];
    func();
}

function drawGrid(color = 255, fade = 32) {
    push();
    colorMode(RGB);
    stroke(color, fade);
    strokeWeight(1);
    for (let x = 0; x < width; x += 10) line(x, 0, x, height);
    for (let y = 0; y < height; y += 10) line(0, y, width, y);
    pop();
}

function textInfo(title, date, name = "赵海洋爸爸", color = 255) {
    push();
    colorMode(RGB);
    fill(color);
    noStroke();
    text(`作品：${title}`, 30, height - 70);
    text(`作者：${name}`, 30, height - 50);
    text(`日期：${date}`, 30, height - 30);
    pop();
}

function drawVector(vector, color = "#FFFFFF") {
    push();
    fill(color);
    stroke(color);
    line(0, 0, vector.x, vector.y);
    circle(0, 0, 4);
    translate(vector.x, vector.y);
    rotate(vector.heading());
    triangle(0, 0, -4, -2, -4, +2);
    pop();
}

function vectorProjection(v1, v2) {
    const v2n = v2.copy().normalize();
    const sp = v1.dot(v2n);
    return v2n.setMag(sp);
}

function star(x, y, radius1, radius2, npoints) {
    let angle = TWO_PI / npoints;
    let halfAngle = angle / 2.0;
    beginShape();
    for (let a = 0; a < TWO_PI; a += angle) {
        let sx = x + cos(a) * radius2;
        let sy = y + sin(a) * radius2;
        vertex(sx, sy);
        sx = x + cos(a + halfAngle) * radius1;
        sy = y + sin(a + halfAngle) * radius1;
        vertex(sx, sy);
    }
    endShape(CLOSE);
}

// cartesian to polar
function cartesianToPolara(x, y) {
    let v = createVector(x, y);
    return { r: v.mag(), θ: createVector(1, 0).angleBetween(v) };
}

// polar to cartesian
function polarToCartesian(r, θ) {
    return { x: r * cos(θ), y: r * sin(θ) };
}