0 <= 0 not true: what am I missing?

nolan

Hey folks,

Not sure if this is the best way of achieving what I want, but I'm trying to normalize rotation_degrees to a 0-359 range. I have this:

func normalize_degrees(degrees: float):
  print(degrees)
  if degrees <= float(0):
    print("here")
    return degrees * -1
  else:
    print("here2")
    return 360 - degrees

BUt sometimes what I'm logging is:

0
here2

That is, a value of 0 triggers the second path, whereas it should trigger the <= 0 path.

First, is there a better way to normalize degrees if I want a value from 0-359?

And second, why am I getting this oddness? I'm assuming the string conversion is losing some insignificant decimals that are throwing off the check? If so, how do I display the exact float value, and how would I check if the <= operator is within some certain margin of error from 0? Maybe there's a helper function for this?

Thanks, can't believe I'm struggling with a simple <= check. :)

TwistedTwigleg

I don't know for sure, but the issue is probably that either degrees or float(0) is returning something like 0.0002 instead of 0, which is causing the condition to fail. This issue occurs because of floating point precision.

The way I have found to work around the issue is to multiply the angle by 100, use the round function to remove the floating points, cast the rounded result to an integer to get rid of the floating point precision issue, and finally divide the result by 100 so that the angle is back to a decimal. The code for this looks like this:

angle_to_convert = int(round(angle_to_convert * 100)) / 100.0;

This will work around the floating point precision issue, as numbers like 0.0002 will be converted to 0.00, dropping the two entirely.

If your angle is in the -180 to 180 range, converting it to 0 to 360 depends on where you want 0 rotation to be. For my projects, I just check if the angle is under 0 and if it is, I take 360 and add the rotation to it. Because the rotation is negative, this will remove from 360, leading to the angle getting progressively larger as the negative angle gets smaller. That will change the angle range so it is within 0 to 360, where 0 is in the same position as the Godot editor.

Hopefully this helps!

nolan

Thanks! It was indeed a case of print(degrees) truncating after a number of 0s. I checked the value of decimals(degrees), which was 7 in this instance. So in that case, I set the value to 0. Interesting that print didn't give me an exact value, but in any case it works now.