Circle coordinates to array in Javascript?

Question

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)); } }

Answer 1

You are on the right track. :)

Let's just modify that function a little:

let xValues = [];

let yValues = [];

function setCirclePoints(radius, steps, centerX, centerY) {

for (let i = 0; i < steps; i++) {

xValues.push(centerX + (radius * Math.cos(2 * Math.PI * (i/steps))));

yValues.push(centerY + (radius * Math.sin(2 * Math.PI * (i/steps))));

}

}

setCirclePoints(1,40,0,0);

console.log (xValues);

console.log (yValues);

To find the x value at any step we need the radius multiplied by the cosine of the angle in radians. The angle in radians is 2pi x the percentage of the way around the circle.

Same for y, but use sine.