NAME

       vpClassifyScanline  - incrementally create a preclassified volume from scanlines of scalar
       data

SYNOPSIS

       #include <volpack.h>

       vpResult
       vpClassifyScanline(vpc, voxels)
           vpContext *vpc;
           void *voxels;

ARGUMENTS

       vpc    VolPack context from vpCreateContext.

       voxels 1D array of voxel data.

DESCRIPTION

       vpClassifyScanline is used to incrementally compute a preclassified volume by  classifying
       one scanline of voxels and storing the result in the current preclassified volume.

       The  voxels  argument  is  a 1D array containing voxels in the format previously specified
       with vpSetVoxelSize and vpSetVoxelField.  vpVolumeSize must be called to declare the  size
       of  the volume before the first call to vpClassifyScanline, and the length of the 1D voxel
       array must be equal to the length of the X dimension of the volume.  The  1D  voxel  array
       may be initialized with vpScanlineNormals or a user-defined function.

       The  voxels  in  the array are classified using the current opacity transfer function (see
       vpSetClassifierTable(3))   and    appended    to    the    preclassified    volume    (see
       vpClassifyVolume(3)).   Scanlines must be processed in Z-major order: all of the scanlines
       in the Z=0 slice are processed from Y=0 onward, then the Z=1 slice is  processed,  and  so
       on.   When  the  last  scanline  in  the  volume has been processed the preclassified data
       structure is ready to be  used  for  rendering.   Rendering  is  not  possible  until  all
       scanlines have been processed.

       When  the  first  scanline  of  a  volume  is  passed  to vpClassifyScanline, any existing
       preclassified volume data is destroyed.

ERRORS

       The normal return value is VP_OK.  The following error return values are possible:

       VPERROR_BAD_VOXEL
              The voxel size or the voxel fields have not been specified or have been incorrectly
              specified.

       VPERROR_BAD_CLASSIFIER
              The  opacity  transfer  function  tables  have invalid sizes or are associated with
              invalid voxel fields or have been incorrectly specified.

SEE ALSO

       VolPack(3),     vpCreateContext(3),     vpSetClassifierTable(3),      vpClassifyVolume(3),
       vpClassifyScalars(3)