Provided by: libvolpack1-dev_1.0b3-9_amd64 
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,
240u'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,
240u'float *r_ptr, float *r_ptr,
240u'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,
264u'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,
240u'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)