Rotating a GameObject

Hi,
I am new to coding with unity but I thought I would get a simple code like this to work but nevermind.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class RotateByTouch : MonoBehaviour {
6.  
7.     public GameObject Objekt;
8.     private Quaternion pos;
9.  
10.     // Update is called once per frame
11.     void Update()
12.     {
13.         pos = Objekt.transform.rotation;
14.        
15.  
16.         foreach (Touch touch in Input.touches) {
17.  
18.             if (touch.phase == TouchPhase.Began || touch.phase == TouchPhase.Moved || touch.phase == TouchPhase.Stationary) // || or    | and
19.             {
20.                 if (pos.z.Equals(0))
21.                 {
22.                     pos.SetEulerRotation(0, 0, -45);
23.                 }
24.             }else if (touch.phase == TouchPhase.Ended || touch.phase == TouchPhase.Canceled)
25.             {
26.                 if (pos.z.Equals(-45))
27.                 {
28.                     pos.SetEulerRotation(0, 0, 0);
29.                 }
30.                
31.             }
32.         }
33.     }
34. }
35.  

I am trying to rotate a GameObject but it doesn't work.

 

mabye as guide https://answers.unity.com/questions/1568958/rotate-object-with-touch-1.html

 

The most obvious thing here is that Quaternion is a struct, which means that it's copied by value and not reference. Or, to put it more plainly, lines 22 and 28 are modifying a copy of the rotation, and not the GameObject's rotation itself. You'll have to assign the rotation to the desired value like:

Code (csharp):

1. //do this after you set the value of pos:
2. Objekt.transform.rotation = pos;
3. //or just do it directly on lines 22/28:
4. Objekt.transform.rotation = Quaternion.Euler(0,0,-45);

Also, on lines 20 and 26, you're checking against the Z component of a rotation, which is not what you think it is. Quaternions have 4 numbers (x,y,z,w) and none of them are clear analogs to the X, Y, and Z that you see in the inspector. A little more reading about this here, but the short version is, don't use rotation.x if you haven't studied quaternions. rotation.eulerAngles.x is more like the number you want.

But wait! There's more!
You're currently checking to see if (after using the correction above) rotation.eulerAngles.x == 45. The numbers in the rotation object (like most numbers in Unity) are floating point numbers, and there's something important to know about floating point numbers: they are imprecise. What this means is that, with very rare exceptions, you should never use == (or .Equals) with floating point numbers, because if you do any math on them, then it can very easily be 44.9999999999, and give you a false negative. (Though it may not seem like you're "doing math" on this number, your Euler angles are being converted to a Quaternion and then back to a Euler number behind the scenes, which counts.) In a lot of cases you can check for a range, like:

Code (csharp):

1. if ( Mathf.Abs (rotation.eulerAngles.x - 45) < 0.001)

However, there's an easier way in this case, because in this case you're basically just flipping between two possible states:

Code (csharp):

1. bool flipped = false;
2. if (Input.touch blah blah blah) {
3.    flipped = !flipped; //reverse the value between true and false
4. }
5. ...
6. if (flipped) {
7.    transform.rotation = Quaternion.Euler(-45,0,0);
8. }
9. else {
10.    transform.rotation = Quaternion.Euler(0,0,0);
11. }

 

Ok wow thank you so much! That is how much you can do wrong in 34 lines of code.

 

Or put another way: this is how many lessons can be taught with 34 lines of code

 

yeah, I agree with StarManta, also you could do a lot more wrong in 34 lines of code.

in fact only one would be enough

nuclearMissileRange.GetSilo(Random.Range(0, 16)).Launch(disallowAbort: true);

just imagine 34 of them....