在画布上水平移动对象

Question

I need the object to move left to right, but in the code I have, it keeps right to left and goes back left to right:

function draw() {
    var time = new Date().getTime() * 0.002;
    var x = Math.sin(time * 0.5)*700
    var y = 58;

The problem is in line 3 .

Answer 1

Math.sin values oscillate between -1 and 1, which is why you're seeing your object go from right to left then back to right again. It's cycling through the min and max of Math.sin.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Math/sin

Use this instead of Math.sin to achieve the desired effect: var x += time;

Answer 2

Why are you using Math.sin? just use this:

var x += time;