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vpSetCallback(3) Library Functions Manual vpSetCallback(3) 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-preci- sion 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 vpSet- LookupShader(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 de- clared: 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 in- tensities of the result. Each intensity should be a sin- gle-precision floating point in the range 0.0 (no inten- sity) 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 vpSet- LookupShader(3) for more information. VP_READ_FUNC The func argument is a callback function that takes the same ar- guments and returns the same result as the read(2) system call. This function is used to read data from files (see vpLoadRawVol- ume(3)). By default, the read system call is used. The call- back can be used to implement a custom I/O interface, for exam- ple a compression/decompression system. VP_WRITE_FUNC The func argument is a callback function that takes the same ar- guments and returns the same result as the write(2) system call. This function is used to write data to files (see vpStoreRawVol- ume(3)). By default, the write system call is used. The call- back can be used to implement a custom I/O interface, for exam- ple a compression/decompression system. VP_MMAP_FUNC The func argument is a callback function that is called to mem- ory 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 off- set. By default, memory mapping is disabled. VP_STATUS_FUNC The func argument is a callback function that is called periodi- cally during long-running operations such as during preprocess- ing 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 inter- nal 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 allo- cator. file Source code file name for the call to the memory alloca- tor. 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 (primar- ily 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 be- havior. 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), vpSetLookup- Shader(3), vpLoadRawVolume(3), vpStoreRawVolume(3) VolPack vpSetCallback(3)
NAME | SYNOPSIS | ARGUMENTS | DESCRIPTION | ERRORS | SEE ALSO
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