javascript - 生成 40 个具有最小/最大和固定时间的随机间隔
问题描述
我正在制作一个总游戏时间为 180 秒的游戏,在这 180 秒内,需要随机出现40 个项目。听起来很容易对吧?有一个问题:项目之间的最小延迟不能小于 1 秒,也不能高于 10 秒。
所以到目前为止我得到的是:
const config = {};
config.squidAppearances = 40;
const spawnTimeLastSquid = 180 - 2;
const fixedDelay = spawnTimeLastSquid / config.squidAppearances;
// Fixed delay would be 4.5
const maxDiff = Math.floor(fixedDelay);
let values = [];
let squidIntervals = [];
for (let i = 0; i < (config.squidAppearances); ++i) {
// Here's the formula:
const plusOrMinus = Math.random() < 0.5 ? -1 : 1;
const offset = Math.random() * maxDiff * plusOrMinus;
let current = (fixedDelay * i + offset);
if (values.length > 1) {
var prev = values[values.length - 1];
if ((current - prev) > 10) current = prev - 10;
if ((current - prev) < 1) current = prev + 1;
// I'm saving the delay for each squid so I can do setTimeout()
squidIntervals.push(current - prev);
} else {
// Spawn time would be this:
squidIntervals.push(fixedDelay * i + offset);
}
// Save values so we can use the previous value on next iteration
values.push(current);
}
// Last squid delay
squidIntervals.push(180 - spawnTimeLastSquid);
console.log(values);
(或作为小提琴)
检查你的控制台,每次运行它都会得到非常不同的结果。有时它看起来像它的工作,但大多数其他时候生成时间不会分布在 0(秒)和 180 之间,或者数组中每个项目的延迟是 1000。
我在这里做什么?
解决方案
我会做这样的事情:
为每个 squid 生成间隔 [1;10],计算总时间,通常 > 180,所以现在你可以减少随机间隔直到达到持续时间限制:
function generateObjects() {
let r = [];
let s = 0;
for (let i=0; i<40; i++) {
let d = Math.floor(Math.random()*10) + 1;
r[i] = d;
s += d; // total duration
}
while (s >= 180.) {
let d = Math.random();
let i = Math.floor(Math.random()*40);
if (r[i]-d >= 1.0) {
r[i] -= d;
s -= d;
}
}
// to be sure here you could have similar to above while (s < 180.) loop and increase random interval to fully fill 180 seconds, if you want
return r;
}
function drawObjects(objs) {
let c = document.getElementById('canvas').getContext('2d', {alpha: false});
c.fillStyle = 'whitesmoke';
c.fillRect(0, 0, 360, 10);
c.fillStyle = 'black';
let s = 0;
for (let i=0; i<objs.length; i++) {
s += objs[i];
c.fillRect(2*s, 0, 1, 10);
}
}
drawObjects(generateObjects());
<canvas id="canvas" width="360" height="10"></canvas>