Axis which should have the smallest stride after transposing
(VP_X_AXIS, VP_Y_AXIS or VP_Z_AXIS).
DESCRIPTION
vpTranspose is used to transpose the 3D voxel array to optimize
the memory stride for a particular principal viewing axis. The
intended way to use this function is to set the viewing
transformation, call vpGeti with the VP_VIEW_AXIS argument to
find the corresponding viewing axis, and then call vpTranspose
with that axis. Transposing the data changes the arrangement of the
data stored in the 3D voxel array. The voxel stride state variables
are updated to reflect this change, so the viewing transformation does
not need to be changed after transposing. If the volume is already
transposed for the requested axis then it returns immediately without
modifying the voxel array.
This function is useful only for rendering large 3D voxel
arrays. This function has no affect on the preclassified volume data.
STATE VARIABLES
Relevant variables may be retrieved with the following state variable
codes (see vpGeti(3)): VP_VIEW_AXIS, VP_VOXEL_XSTRIDE, VP_VOXEL_YSTRIDE,
VP_VOXEL_ZSTRIDE.
ERRORS
The normal return value is VP_OK. The following error return values
are possible: