It is similar to Basis, which implements matrix representation of rotations, and can be parametrized using both an axis-angle pair or Euler angles. Basis stores rotation, scale, and shearing, while Quaternion only stores rotation.
Due to its compactness and the way it is stored in memory, certain operations (obtaining axis-angle and performing SLERP, in particular) are more efficient and robust against floating-point errors.
</description>
<tutorials>
<linktitle="Using 3D transforms">$DOCS_URL/tutorials/3d/using_transforms.html#interpolating-with-quaternions</link>
<linktitle="Third Person Shooter Demo">https://godotengine.org/asset-library/asset/678</link>
Constructs a quaternion that will perform a rotation specified by Euler angles (in the YXZ convention: when decomposing, first Z, then X, and Y last), given in the vector format as (X angle, Y angle, Z angle).
Returns the angle between this quaternion and [code]to[/code]. This is the magnitude of the angle you would need to rotate by to get from one to the other.
[b]Note:[/b] This method has an abnormally high amount of floating-point error, so methods such as [method @GDScript.is_zero_approx] will not work reliably.
Performs a cubic spherical interpolation between quaternions [code]pre_a[/code], this vector, [code]b[/code], and [code]post_b[/code], by the given amount [code]weight[/code].
Returns Euler angles (in the YXZ convention: when decomposing, first Z, then X, and Y last) corresponding to the rotation represented by the unit quaternion. Returned vector contains the rotation angles in the format (X angle, Y angle, Z angle).
Returns [code]true[/code] if this quaternion and [code]quat[/code] are approximately equal, by running [method @GDScript.is_equal_approx] on each component.
</description>
</method>
<methodname="is_normalized">
<returntype="bool"/>
<description>
Returns whether the quaternion is normalized or not.
Returns a copy of the quaternion, normalized to unit length.
</description>
</method>
<methodname="set_axis_angle">
<argumentindex="0"name="axis"type="Vector3"/>
<argumentindex="1"name="angle"type="float"/>
<description>
Sets the quaternion to a rotation which rotates around axis by the specified angle, in radians. The axis must be a normalized vector.
</description>
</method>
<methodname="set_euler">
<argumentindex="0"name="euler"type="Vector3"/>
<description>
Sets the quaternion to a rotation specified by Euler angles (in the YXZ convention: when decomposing, first Z, then X, and Y last), given in the vector format as (X angle, Y angle, Z angle).
Returns the result of the spherical linear interpolation between this quaternion and [code]to[/code] by amount [code]weight[/code], but without checking if the rotation path is not bigger than 90 degrees.
The identity quaternion, representing no rotation. Equivalent to an identity [Basis] matrix. If a vector is transformed by an identity quaternion, it will not change.
