rtcSetGeometryTransformQuaternion(3) Embree Ray Tracing Kernels 3 rtcSetGeometryTransformQuaternion(3) 

rtcSetGeometryTransformQuaternion - sets the transformation for a particular
  time step of an instance geometry as a decomposition of the
  transformation matrix using quaternions to represent the rotation.


#include <embree3/rtcore.h>
void rtcSetGeometryTransformQuaternion(
  RTCGeometry geometry,
  unsigned int timeStep,
  const struct RTCQuaternionDecomposition* qd
);

The rtcSetGeometryTransformQuaternion function sets the local-to-world affine transformation (qd parameter) of an instance geometry (geometry parameter) for a particular time step (timeStep parameter). The transformation is specified as a [RTCQuaternionDecomposition], which is a decomposition of an affine transformation that represents the rotational component of an affine transformation as a quaternion. This allows interpolating rotational transformations exactly using spherical linear interpolation (such as a turning wheel).

For more information about the decomposition see [RTCQuaternionDecomposition]. The quaternion given in the RTCQuaternionDecomposition struct will be normalized internally.

For correct results, the transformation matrices for all time steps must be set either using rtcSetGeometryTransform or rtcSetGeometryTransformQuaternion. Mixing both representations is not allowed. Spherical linear interpolation will be used, iff the transformation matizes are set with rtcSetGeometryTransformQuaternion.

For an example of this feature see the tutorial [Quaternion Motion Blur].

On failure an error code is set that can be queried using rtcGetDeviceError.

[rtcInitQuaternionDecomposition], [rtcSetGeometryTransform]