Feature request : toFixed() for vectors value

Feature request

It would be nice to add a parameter to Vector3.round() and Vector3.roundToZero(), to ask for a number of decimal like Number.toFixed() in JS. If undefined, it would assume that an integer is needed, so it would not break anything.

Use case

I had to do my own function to do that, because the objects in my scene are user-transformed, then the transforms are exported as JSON. There is a big tolerance, so in order to reduce file size, I round the vector3 values. But rounding to integer is too much, that’s why I did my own function. I guess that it would also be useful in things like voxel-painter or Minecraft-likes.

I thought it might not be a big deal to add it to three.js, and it’s useful, hence my feature request. If you think it’s useless code, please close the issue.

[Mugen87]

We should not use Number.toFixed() since it returns a string. It seems that number-to-string conversion just for rounding is no good approach.

https://stackoverflow.com/questions/2283566/how-can-i-round-a-number-in-javascript-tofixed-returns-a-string#comment47147413_14978830

Can you please test if this would work for you:

THREE.Vector3.prototype.round = function( digits ) {

    var e = Math.pow( 10, digits || 0 );

    this.x = Math.round( this.x * e ) / e;
    this.y = Math.round( this.y * e ) / e;
    this.z = Math.round( this.z * e ) / e;
        
    return this;

}

Live example (check browser console): https://glitch.com/~meowing-bougon

However, I don’t think this logic makes sense for Vector3.roundToZero().

[Mugen87]

The semantics of Number.toFixed() and Vector3.toFixed() would be different since the native function returns a string. Hence, it’s confusing to reuse the same name.

I think enhancing the methods is okay. If we can solve the issue @sciecode mentioned.