How to compare two quaternions?

Hey guys,

Seems like I found the worst way to do it:

Code (csharp):

1.         bool RotationEquals(Quaternion r1, Quaternion r2)
2.         {
3.             float abs = Mathf.Abs(Quaternion.Dot(r1, r2));
4.             if (abs >= 0.9999999f)
5.                 return true;
6.             return false;
7.         }

How exactly should I use Quaternion.Angle instead of this crap in my case?

Thanks

 

Is it possible to do without epsilon at all?

 

Judging by the doc it would appear what you wrote is basically what the equality operator overload for Quaternion does. http://docs.unity3d.com/Documentation/ScriptReference/Quaternion-operator_eq.html

 

bool compareQuaternion(Quaternion q1,Quaternion q2)
{
if (q1.x == q2.x&& q1.y == q2.y && q1.z == q2.z && q1.w == q2.w)
{
return true;
}

return false;
}

 

Except not because comparing floats like that is a no-no

 

I have something like this:

Code (CSharp):

1. Quaternion q1= xxxx;
2. Quaternion q2= yyyy;
3. while (q1 != q2)
4.     {
5.         q1 = Quaternion.Lerp(q1, q2, rotationSpeed * Time.deltaTime);
6.         Debug.Log(Mathf.Abs(Quaternion.Dot(q1,q2)));
7.         yield return null;
8.     }

And if I see in log:

Code (CSharp):

1. Mathf.Abs(Quaternion.Dot(q1,q2))==1

then the cycle becomes infinite. That is, if quaternions become absolutely equal, then the condition is not fulfilled for some reason. And it happens sometimes.
But if condition:

Code (CSharp):

1. Mathf.Abs(Quaternion.Dot(q1,q2))==0.999999x

then the cycle breaks correctly.
So the top option isn’t so bad

 

I changed code to:

Code (CSharp):

1. Quaternion q1= xxxx;
2. Quaternion q2= yyyy;
3. while (Mathf.Abs(Quaternion.Dot(q1,q2))<0.999999f)
4.     {
5.         q1 = Quaternion.Lerp(q1, q2, rotationSpeed * Time.deltaTime);
6.         Debug.Log(Mathf.Abs(Quaternion.Dot(q1,q2)));
7.         yield return null;
8.     }

Now it works more stable.