planck-js/src/common/Math.ts

2D JavaScript/TypeScript physics engine for cross-platform HTML5 game development

/*
 * Planck.js
 *
 * Copyright (c) Erin Catto, Ali Shakiba
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */

/** @internal */ const math_random = Math.random;


export const EPSILON = 1e-9;

/** @internal @deprecated */
export const isFinite = Number.isFinite;

/**
 * @deprecated
 * Next Largest Power of 2 Given a binary integer value x, the next largest
 * power of 2 can be computed by a SWAR algorithm that recursively "folds" the
 * upper bits into the lower bits. This process yields a bit vector with the
 * same most significant 1 as x, but all 1's below it. Adding 1 to that value
 * yields the next largest power of 2. For a 32-bit value:
 */
export function nextPowerOfTwo(x: number): number {
  x |= (x >> 1);
  x |= (x >> 2);
  x |= (x >> 4);
  x |= (x >> 8);
  x |= (x >> 16);
  return x + 1;
}

/** @deprecated */
export function isPowerOfTwo(x: number): boolean {
  return x > 0 && (x & (x - 1)) === 0;
}

/** @deprecated */
export function mod(num: number, min?: number, max?: number): number {
  if (typeof min === "undefined") {
    max = 1;
    min = 0;
  } else if (typeof max === "undefined") {
    max = min;
    min = 0;
  }
  if (max > min) {
    num = (num - min) % (max - min);
    return num + (num < 0 ? max : min);
  } else {
    num = (num - max) % (min - max);
    return num + (num <= 0 ? min : max);
  }
}

/**
 * @deprecated
 * Returns a min if num is less than min, and max if more than max, otherwise returns num.
 */
export function clamp(num: number, min: number, max: number): number {
  if (num < min) {
    return min;
  } else if (num > max) {
    return max;
  } else {
    return num;
  }
}

/**
 * @deprecated
 * Returns a random number between min and max when two arguments are provided.
 * If one arg is provided between 0 to max.
 * If one arg is passed between 0 to 1.
 */
export function random(min?: number, max?: number): number {
  if (typeof min === "undefined") {
    max = 1;
    min = 0;
  } else if (typeof max === "undefined") {
    max = min;
    min = 0;
  }
  return min === max ? min : math_random() * (max - min) + min;
}

/** @ignore */
export const math = Object.create(Math);
math.EPSILON = EPSILON;
math.isFinite = isFinite;
math.nextPowerOfTwo = nextPowerOfTwo;
math.isPowerOfTwo = isPowerOfTwo;
math.mod = mod;
math.clamp = clamp;
math.random = random;