rotationMatrix(atTime:)
Returns the orientation of the transform as a rotation matrix, as of the specified time sample.
Declaration
func rotationMatrix(atTime time: TimeInterval) -> matrix_float4x4Parameters
- time:
The time sample for which to request information.
Return Value
The orientation, as a rotation matrix, of the transform.
Discussion
A rotation matrix provides the same information as the vector returned by the rotation(atTime:) method, but in a form more convenient for multiplying with position vectors.
Together with the translation, scale, and shear factors, rotation information defines the local coordinate space for any object affected by the transform, relative to a parent coordinate space. To work with the complete transform, use the localTransform(atTime:) and setLocalTransform(_:forTime:) methods.
Requesting a sample outside the time range clamps results to the minimumTime or maximumTime sample. Some asset formats support continuous sampling with interpolation for times between the samples stored in the asset; others are discrete. For an asset with discrete time information, requesting a sample time in between the samples stored in the asset returns data for the immediately preceding time.