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)

VolPack                                                                                    vpClassifyScanline(3)