Why would a rotation have float point errors when going clockwise, but not counterclockwise?

Questions & Answers
1

I’m using this code to rotate a cube on a button press. It’s been infuriating to get to this point but this script ended up working well. Anyways, I noticed when I press the button that rotates the cube clockwise four times, it goes from 0 to 90 to 180 to 270 but then back to a very small number that’s not exactly 0 (I think it was like 1.10017001e2 or something)

Case in point, clockwise rotation = not back to zero after four button presses. However, the same thing doesn’t occur when i rotate counterclockwise.

I can press the button four times and it goes back to zero exactly. Any idea why this might be happening?

(here’s the code)

using UnityEngine;
using System;
using System.Collections;
 
public class Example : MonoBehaviour {
 
    int rotCount = 0;
    bool inmotion = false;

    void Update() {
        if (Input.GetKeyDown("e") && !inmotion) {
            rotCount = (rotCount + 1) % 4;
            DoRotation();
        }
         
        if (Input.GetKeyDown("q") && !inmotion) {
            rotCount = (rotCount - 1) % 4;
            DoRotation();
        }
    }
     
    void DoRotation() {
        inmotion = true;
        int rot = rotCount * 90;
        iTween.RotateTo(gameObject, iTween.Hash("y",rot,"oncomplete","EndRotation","time",1.00));
    }
     
    void EndRotation() {
        inmotion = false;
    }
}
2

That’s just the nature of floating-point maths - it’s inherently imprecise, and you should never rely on it having an exact value.