Provided by: libvolpack1-dev_1.0b3-3_amd64 bug

NAME

       vpSetCallback - define a callback function

SYNOPSIS

       #include <volpack.h>

       vpResult
       vpSetCallback(vpc, option, func)
           vpContext *vpc;
           int option;
           void (*func)();

ARGUMENTS

       vpc    VolPack context from vpCreateContext.

       option A code specifying which callback function to set.

       func   A pointer to the callback function.

DESCRIPTION

       vpSetCallback  is  used to set a callback function.  The following list gives the possible
       values for option:

       VP_GRAY_SHADE_FUNC
              The func argument is a shading callback function that  produces  a  floating  point
              grayscale pixel intensity.  The function should be declared:
              void func(void *voxel_ptr, float *i_ptr,
                        void *client_data);

              voxel_ptr
                     Pointer to the beginning of a voxel that must be shaded.

              i_ptr  Location  into  which  the  function  should  store  the grayscale intensity
                     result.  It should be a single-precision floating point  in  the  range  0.0
                     (black) to 1.0 (white).

              client_data
                     Pointer to the application-defined client data (see vpSetClientData(3)).

              The  callback  can  be  used  to  implement  custom shading routines that cannot be
              implemented with a lookup table.  See vpSetLookupShader(3) for more information.

       VP_RGB_SHADE_FUNC
              The func argument is a shading callback function that produces a floating point RGB
              pixel intensity.  The function should be declared:
              void func(void *voxel_ptr, float *r_ptr,
                        float *r_ptr, float *r_ptr,
                        void *client_data);

              voxel_ptr
                     Pointer to the beginning of a voxel that must be shaded.

              r_ptr, g_ptr, b_ptr
                     Location  into  which  the  function should store the RGB intensities of the
                     result.  Each intensity should be a single-precision floating point  in  the
                     range 0.0 (no intensity) to 1.0 (full intensity).

              client_data
                     Pointer to the application-defined client data (see vpSetClientData(3)).

              The  callback  can  be  used  to  implement  custom shading routines that cannot be
              implemented with a lookup table.  See vpSetLookupShader(3) for more information.

       VP_READ_FUNC
              The func argument is a callback function that takes the same arguments and  returns
              the  same  result  as  the read(2) system call.  This function is used to read data
              from files (see vpLoadRawVolume(3)).  By default, the read  system  call  is  used.
              The  callback  can  be  used  to  implement  a  custom I/O interface, for example a
              compression/decompression system.

       VP_WRITE_FUNC
              The func argument is a callback function that takes the same arguments and  returns
              the  same  result as the write(2) system call.  This function is used to write data
              to files (see vpStoreRawVolume(3)).  By default, the write  system  call  is  used.
              The  callback  can  be  used  to  implement  a  custom I/O interface, for example a
              compression/decompression system.

       VP_MMAP_FUNC
              The func argument is a callback function that is called to memory map data  from  a
              file  instead  of  copying  the  data  into  memory  (see vpLoadRawVolume(3)).  The
              function should be declared:
              void *func(int fd, unsigned offset,
                         void *client_data);

              fd     File descriptor from open(2) open for reading.

              offset Byte offset in the file to the beginning of the memory to be mapped.

              client_data
                     Pointer to the application-defined client data (see vpSetClientData(3)).

              The function should map the entire file into memory and return  a  pointer  to  the
              memory location that corresponds to the file offset.  By default, memory mapping is
              disabled.

       VP_STATUS_FUNC
              The func argument is a callback function that is called periodically  during  long-
              running  operations  such as during preprocessing of a volume.  The function should
              be declared:
              void func(double frac, void *client_data);

              frac   An estimate of the fraction of the current operation that is complete.

              client_data
                     Pointer to the client data associated with the context.

              The callback can be used to print a  status  report  or  to  process  time-critical
              events  such  as  user  input.   However, the callback should not make any calls to
              VolPack functions since the internal VolPack state may be inconsistent.

       VP_LOG_ALLOC_FUNC
              The func argument is a callback function that is called whenever VolPack  allocates
              memory.  The function should be declared:
              void func(void *ptr, int size, char *use,
                        int line, char *file, void *client_data);

              ptr    Address of the allocated memory.

              size   Size (in bytes) of the allocated memory.

              use    Short description of the use of the allocated memory.

              line   Source code line number for the call to the memory allocator.

              file   Source code file name for the call to the memory allocator.

              client_data
                     Pointer to the client data associated with the context.

              The  callback  can  be  used  to  track memory allocations (primarily for debugging
              memory leaks).

       VP_LOG_FREE_FUNC
              The  func  argument  is  a  callback  function  that  is  called  whenever  VolPack
              deallocates memory.  The function should be declared:
              void func(void *ptr, void *client_data)

              ptr    Address of the deallocated memory.

              client_data
                     Pointer to the client data associated with the context.

              The  callback  can  be  used to track memory deallocations (primarily for debugging
              memory leaks).

       If the func argument is NULL then the corresponding callback  function  is  reset  to  the
       default behavior or disabled if there is no default behavior.

ERRORS

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

       VPERROR_BAD_OPTION
              The option argument is invalid.

SEE ALSO

       VolPack(3),       vpCreateContext(3),       vpSetClientData(3),      vpSetLookupShader(3),
       vpLoadRawVolume(3), vpStoreRawVolume(3)