util.js

/** Global Parameters Object */
const params = {
    debug: false,
    hardcore: false,
    fps: 60,
    totaltime: 0,
    cache: [],
};

/**
 * @param {Number} n
 * @returns Random Integer Between 0 and n-1
 */
const randomInt = (n) => Math.floor(Math.random() * n);

/**
 * @param {Number} r Red Value
 * @param {Number} g Green Value
 * @param {Number} b Blue Value
 * @returns String that can be used as a rgb web color
 */
const rgb = (r, g, b) => `rgba(${r}, ${g}, ${b})`;

/**
 * @param {Number} r Red Value
 * @param {Number} g Green Value
 * @param {Number} b Blue Value
 * @param {Number} a Alpha Value
 * @returns String that can be used as a rgba web color
 */
const rgba = (r, g, b, a) => `rgba(${r}, ${g}, ${b}, ${a})`;

/**
 * @param {Number} h Hue
 * @param {Number} s Saturation
 * @param {Number} l Lightness
 * @returns String that can be used as a hsl web color
 */
const hsl = (h, s, l) => `hsl(${h}, ${s}%, ${l}%)`;

/** Creates an alias for requestAnimationFrame for backwards compatibility */
window.requestAnimFrame = (() => {
    return (
        window.requestAnimationFrame ||
        window.webkitRequestAnimationFrame ||
        window.mozRequestAnimationFrame ||
        window.oRequestAnimationFrame ||
        window.msRequestAnimationFrame ||
        /**
         * Compatibility for requesting animation frames in older browsers
         * @param {Function} callback Function
         * @param {DOM} element DOM ELEMENT
         */
        ((callback, element) => {
            window.setTimeout(callback, 1000 / 60);
        })
    );
})();

/**
 * Returns distance from two points
 * @param {Number} p1, p2 Two objects with x and y coordinates
 * @returns Distance between the two points
 */
const getDistance = (p1, p2) => {
    return Math.sqrt(Math.pow(p2.x - p1.x, 2) + Math.pow(p2.y - p1.y, 2));
};

/**
 * Simple linear interpolation
 * @param {Number} start position of original
 * @param {Number} end position of target
 * @param {Number} amount amount of interpolation between 0.00 and 1.00
 * @returns the lerped or percentage in between the start and end values
 */
const lerp = (start, end, amount) => {
    return start + (end - start) * amount;
};