Wierd behaviour on Burst count using rand function

[Sandstedt]

When setting the burst count using the rand() function, the burst behaves wierdly, or random, too random. Sometimes the children are not spread out evenly, sometimes it's like the last childs is still playing. Compare this to when you set either count to, 2, 3, 4, 5 or 6 directly compared to 'rand(2, 6)'.

Example:

const example = new mojs.Burst({
  parent: '#example',
  x: 'rand(-50, 50)',
  y: 'rand(-50, 50)',
  count: 'rand(2, 6)'
});

document.addEventListener( 'click', function (e) {
  example.generate().replay();
});

Bug reproduction pen:
https://codepen.io/sandstedt/pen/Vwjdroy

[xavierfoucrier]

@Sandstedt Good catch! Looks like a bug 🐛

[AlexHRodrii]

This isn't a bug. There are two problems here @Sandstedt.

1. When you use the rand function without truncating the result the rand function generates decimal values that causes the library to generate the particles in a wrong way.
2. In the code you wrote the library will always generate the same number of particles when you click because the example constant is stored in memory and is not regenerated when you click the button.

The solution to your code and to get what you expected from the library is the following:

document.addEventListener( 'click', function (e) {
  new mojs.Burst({
  x: 'rand(-50, 50)',
  y: 'rand(-50, 50)',
  count: Math.floor(Math.random() * (6 - 2 + 1) + 2)
}).play().generate().replay();
});

[xavierfoucrier]

@AlexHRodrii thanks for testing.

I haven't found the time to dive more into this issue, but from what I remember, it looks related to float stuff regarding the count property when using rand MoJS internal method.

I am keeping this open in order to investigate later.