p5.j​​s库＆＃39; random（）＆＃39;功能？

Question

我试图使用构造函数获得一些练习，但我想出了一个关于random（）函数的错误：

12：未捕获的ReferenceError：未定义random ＆＃34;％c您是否只是尝试使用p5.js的random（）函数？如果是这样，您可能希望将其移动到草图的setup（）函数中。\ n \ n有关详细信息，请参阅：github.com/processing/p5.js/wiki/Frequently-Asked-Questions#why-斜面-I-分配变量-使用-P5-函数和变量先于设置＆＃34;

我可以只在setup（）函数中使用此函数吗？我以前不认为我曾遇到过这个问题。是否有使用类似逻辑的解决方案？

var circles = function(x,y,d,xSpeed,ySpeed) {
this.x = x;
this.y = y;
this.d = d;
this.xSpeed = xSpeed;
this.ySpeed = ySpeed;
}

var circle1 = new circles(random(width),random(height), random(30,55),random(3,19),random(3,19));
var circle2 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));
var circle3 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));
var circle4 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));
var circle5 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));
var circle6 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));


function setup() {
 createCanvas(900,900);

 }

function draw() {

 background(0);
 fill(255,255,0);
 ellipse(circle1.x,circle1.y,circle1.d,circle1.d); 
}

 function moveCircles() {

}

Answer 1

从技术上讲，您可以使用按需全局模式在setup()函数之外使用此函数，正如文档所述。但是，如果您没有使用任何其他第三方库，建议仅在setup()函数内使用此函数。

设置前

p5功能

new p5();  // you need to call this fn first

var circle1 = new circles(random(width),random(height), random(30,55),random(3,19),random(3,19));
var circle2 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));
var circle3 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));
var circle4 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));
var circle5 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));
var circle6 = new circles(random(width),random(height), random(30,55), random(3,19),random(3,19));

p5函数insde setup

var circle1, circle2, circle3, circle4, circle5, circle6;

function setup() {
    createCanvas(900, 900);
    circle1 = new circles(random(width), random(height), random(30, 55), random(3, 19), random(3, 19));
    circle2 = new circles(random(width), random(height), random(30, 55), random(3, 19), random(3, 19));
    circle3 = new circles(random(width), random(height), random(30, 55), random(3, 19), random(3, 19));
    circle4 = new circles(random(width), random(height), random(30, 55), random(3, 19), random(3, 19));
    circle6 = new circles(random(width), random(height), random(30, 55), random(3, 19), random(3, 19));
}