Fixing negative rotations

Trying to make it so that when I press the forward key, the player turns in the direction of the camera.
While it works when the camera has a positive rotation, it doesn't when it has a negative rotation. How do I fix it?
Tried this:

Code (csharp):

1.  
2. if(Input.GetAxis("Vertical")>0){
3.             transform.rotation=Quaternion.Euler(transform.rotation.x,cam.rotation.y*180,transform.rotation.z);
4.             if(cam.rotation.y <0){
5.                 Quaternion temprot = Quaternion.Inverse(cam.rotation);
6.                 transform.rotation=Quaternion.Euler(transform.rotation.x,temprot.y*180,transform.rotation.z);
7.             }
8.         }
9.     }
10.  

 

Welcome to Gimbal Lock. Use transform.Rotate()

 

Tried a different method, but there's now a similar issue.

Code (csharp):

1.  
2. float rotdif = cam.rotation.y * 360 - transform.rotation.y*360;
3.         //print(rotdif);
4.         if(rotdif > 20){
5.             transform.Rotate(0,rotspeed*Time.deltaTime,0);
6.         }
7.         if(rotdif < -20){
8.             transform.Rotate(0,-rotspeed*Time.deltaTime,0);
9.         }
10.     }
11.  

When the camera rotation becomes close to 360/0 again, we'll start rotating the wrong way because obviously, 0 is less than 20.

 

Will Mathf.Abs work?

Returns the absolute value

http://unity3d.com/support/documentation/ScriptReference/Mathf.Abs.html

 

Nope.

 

Try multiplying the negative rotation by -1.

 

Considering - * - = +, that would not work. -270 would become 270 while the rotation actually equals 90.
EDIT: obviously, adding 360 would properly do that XD.

Now I need to know how to get it to work when near 0.

 

Let's add a bump. I still have no idea how I work the switch between 359 and 0.

 

There are a few tools, which may be useful for you

Mahtf.Repeat:
http://unity3d.com/support/documentation/ScriptReference/Mathf.Repeat.html

With repeat you can make sure that a certain value is always between 0-n. So if you have

Code (csharp):

1.  
2. float angleX = Mathf.Round(transform.rotation.eulerAngles.x, 360.0f);
3.  

angleX will always be between 0 and 359. Every time it gets above that it will start at 0 and if its negative it will "repeat" itself until its between 0 and 360.

Second your code above seems wrong. You're using Quaternion.Euler(...) but passing quaternion values to into int instead of euler angles.

transform.rotation is a quaternion, and has 4 axis (x, y, z and w which are between 0 and 1 (iirc, maybe also -1 to 1). If you want to pass euler angles, you must use: transform.rotation.eulerAngles.x instead of transform.rotation.x

 

Wouldn't it work if you multiply the rotation with -360 (and if needed divide by 360 afterwards) if the number is negative?

 

Code (CSharp):

1. /// <summary>
2.     /// Clamps any angle to a value between 0 and 360 : -90 = 270
3.     /// </summary>
4.     public static float ClampAngle(float _Angle)
5.     {
6.         float ReturnAngle = _Angle;
7.  
8.         if (_Angle < 0f)
9.             ReturnAngle = (_Angle + (360f * ((_Angle / 360f) + 1)));
10.  
11.         else if (_Angle > 360f)
12.             ReturnAngle = (_Angle - (360f * (_Angle / 360f)));
13.  
14.         else if (ReturnAngle == 360) //Never use 360, only go from 0 to 359
15.             ReturnAngle = 0;
16.  
17.         return ReturnAngle;
18.     }

 

In my case, I just decreased 360 from my angle.

Code (CSharp):

1. if (rotationX > 300f)
2.     rotationX -= 360f;
3. //Where rotationX is the angle measured in float