Possible feature requests for Py5Vector...

[villares]

In Processing you can set the magnitude of a vector to a negative scalar... this will "flip" the heading...

Yesterday at Noite de Processing we were jamming and live coding a "ParticleLife" that was handy...

My solution was:

    v = Py5Vector(100, 100)
    new_mag = -10
    if new_mag < 0:
        v =* -1
        new_mag = -new_mag
    v.mag = new_mag
    print(v)

Could there be a less costly solution inside Py5Vector?

Also Processing "fails silently" to set magnitude to a "null vector". Should we follow that?

[hx2A]

In Processing you can set the magnitude of a vector to a negative scalar... this will "flip" the heading...

That's interesting! Right now the Py5Vector will reject a negative value for the set_mag() method. I think we should allow negative values, like Processing does. This is an easy change.

Also Processing "fails silently" to set magnitude to a "null vector". Should we follow that?

I did some experimenting and I see that this is valid Processing code:

PVector v = new PVector();
v.normalize();
println(v);
// [ 0.0, 0.0, 0.0 ]

py5 would reject the similar code, not allowing you to normalize a vector with a magnitude of zero. This does bother me a bit, but being consistent with Processing is probably the better choice. And if this is allowed in py5, using set_mag() on a zero vector will also be allowed.

[villares]

How about emitting a warning in the zero magnitude vector case? It could help someone with debugging perhaps?

[hx2A]

How about emitting a warning in the zero magnitude vector case? It could help someone with debugging perhaps?

Yes, that's a good idea. And I'll use Python's builtin warnings library to do that. py5 is already using it in a few places. It contains features that let you suppress warning messages if you don't want to be told the same thing over and over.