圆坐标阵列在Javascript [英] Circle coordinates to array in Javascript

问题描述

什么是圆的坐标添加到JavaScript的一个数组的最佳方式？到目前为止，我只能够做一个半圈，但我需要一个返回圆整到两个不同的数组公式：xValues​​和yValues​​。 （我试图获取坐标，所以我可以沿着路径动画的对象。）

下面是我到目前为止有：

 圈：函数（半径，步骤，的centerX，centerY）{
    VAR xValues​​ = [的centerX];
    VAR yValues​​ = [centerY];
    对于（VAR I = 1; I＆LT;步骤;我++）{
    xValues​​ [I] =（的centerX +半径* Math.cos（Math.PI *的i /步骤-Math.PI / 2））;
    yValues​​ [I] =（centerY +半径* Math.sin（Math.PI *的i /步骤-Math.PI / 2））;
   }
}
 

解决方案

您回路应设置这样来代替：

 为（VAR I = 0; I＆LT;步骤;我++）{
    xValues​​ [I] =（+的centerX半径* Math.cos（2 * Math.PI * I /步））;
    yValues​​ [I] =（centerY +半径* Math.sin（2 * Math.PI * I /步））;
}
 

• 在0开始你的循环


• 在整个2 * PI范围步，不只是PI。


• 您不应该在 VAR xValues​​ = [的centerX]; VAR yValues​​ = [centerY]; - 圆的中心不是它的一部分

What's the best way to add the coordinates of a circle to an array in JavaScript? So far I've only been able to do a half circle, but I need a formula that returns the whole circle to two different arrays: xValues and yValues. (I'm trying to get the coordinates so I can animate an object along a path.)

Here's what I have so far:

circle: function(radius, steps, centerX, centerY){
    var xValues = [centerX];
    var yValues = [centerY];
    for (var i = 1; i < steps; i++) {
    	xValues[i] = (centerX + radius * Math.cos(Math.PI * i / steps-Math.PI/2));
    	yValues[i] = (centerY + radius * Math.sin(Math.PI * i / steps-Math.PI/2));
   }
}

解决方案

Your loop should be set up like this instead:

for (var i = 0; i < steps; i++) {
    xValues[i] = (centerX + radius * Math.cos(2 * Math.PI * i / steps));
    yValues[i] = (centerY + radius * Math.sin(2 * Math.PI * i / steps));
}

• Start your loop at 0
• Step through the entire 2 * PI range, not just PI.
• You shouldn't have the var xValues = [centerX]; var yValues = [centerY]; -- the center of the circle is not a part of it.

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