vpRamp - initialize an array with a piecewise-linear ramp

array  Output array.

       stride Stride from one array element to the next, in bytes.

       num_points
              Number of entries in the input arrays (ramp_x and ramp_y).

       ramp_x Input array containing indices into array.

       ramp_y Input array containing values to store into array.

vpRamp  is  a  utility  routine  for initializing linear arrays of floating-point numbers with piecewise-
       linear ramps.  A ramp is defined by a set of (x, y) pairs.  The X coordinates  are  integers  that  index
       entries  in  the array argument, and the Y coordinates are floating-point values to store into the array.
       Linearly-interpolated Y values are stored in array elements with indexes in between two of the X values.

       The values in ramp_x most be strictly increasing.  The stride argument may be used to skip array elements
       or to initialize arrays with a non-standard stride.  If the output array is a simple linear array of type
       float then the stride should be sizeof(float).

       This  function  is  useful  for  creating  lookup  tables  used  for  opacity  transfer  functions   (see
       vpSetClassifierTable(3)) and shading functions (see vpSetLookupShader(3)).

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

       VPERROR_BAD_VALUE
              The number of points is less than one or the X values are not strictly increasing.

       vpRamp - initialize an array with a piecewise-linear ramp

VolPack(3)

VolPack                                                                                                vpRamp(3)

       #include <volpack.h>

       vpResult
       vpRamp(array,stride,num_points,ramp_x,ramp_y)
           float *array;
           int stride;
           int num_points;
           int *ramp_x;
           float *ramp_y;