1vpSetCallback(3) Library Functions Manual vpSetCallback(3)
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6 vpSetCallback - define a callback function
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9 #include <volpack.h>
10 vpResult
12 vpSetCallback(vpc, option, func)
13 vpContext *vpc;
14 int option;
15 void (*func)();
16
18 vpc VolPack context from vpCreateContext.
19 option A code specifying which callback function to set.
21 func A pointer to the callback function.
23
25 vpSetCallback is used to set a callback function. The following list
26 gives the possible values for option:
27 VP_GRAY_SHADE_FUNC
29 The func argument is a shading callback function that produces a
30 floating point grayscale pixel intensity. The function should
31 be declared:
32 void func(void *voxel_ptr, float *i_ptr,
33 void *client_data);
34 voxel_ptr
36 Pointer to the beginning of a voxel that must be shaded.
37 i_ptr Location into which the function should store the
39 grayscale intensity result. It should be a single-preci‐
40 sion floating point in the range 0.0 (black) to 1.0
41 (white).
42 client_data
44 Pointer to the application-defined client data (see
45 vpSetClientData(3)).
46 The callback can be used to implement custom shading routines
48 that cannot be implemented with a lookup table. See vpSet‐
49 LookupShader(3) for more information.
50 VP_RGB_SHADE_FUNC
52 The func argument is a shading callback function that produces a
53 floating point RGB pixel intensity. The function should be
54 declared:
55 void func(void *voxel_ptr, float *r_ptr,
56 float *r_ptr, float *r_ptr,
57 void *client_data);
58 voxel_ptr
60 Pointer to the beginning of a voxel that must be shaded.
61 r_ptr, g_ptr, b_ptr
63 Location into which the function should store the RGB
64 intensities of the result. Each intensity should be a
65 single-precision floating point in the range 0.0 (no
66 intensity) to 1.0 (full intensity).
67 client_data
69 Pointer to the application-defined client data (see
70 vpSetClientData(3)).
71 The callback can be used to implement custom shading routines
73 that cannot be implemented with a lookup table. See vpSet‐
74 LookupShader(3) for more information.
75 VP_READ_FUNC
77 The func argument is a callback function that takes the same
78 arguments and returns the same result as the read(2) system
79 call. This function is used to read data from files (see
80 vpLoadRawVolume(3)). By default, the read system call is used.
81 The callback can be used to implement a custom I/O interface,
82 for example a compression/decompression system.
83 VP_WRITE_FUNC
85 The func argument is a callback function that takes the same
86 arguments and returns the same result as the write(2) system
87 call. This function is used to write data to files (see vpStor‐
88 eRawVolume(3)). By default, the write system call is used. The
89 callback can be used to implement a custom I/O interface, for
90 example a compression/decompression system.
91 VP_MMAP_FUNC
93 The func argument is a callback function that is called to mem‐
94 ory map data from a file instead of copying the data into memory
95 (see vpLoadRawVolume(3)). The function should be declared:
96 void *func(int fd, unsigned offset,
97 void *client_data);
98 fd File descriptor from open(2) open for reading.
100 offset Byte offset in the file to the beginning of the memory to
102 be mapped.
103 client_data
105 Pointer to the application-defined client data (see
106 vpSetClientData(3)).
107 The function should map the entire file into memory and return a
109 pointer to the memory location that corresponds to the file off‐
110 set. By default, memory mapping is disabled.
111 VP_STATUS_FUNC
114 The func argument is a callback function that is called periodi‐
115 cally during long-running operations such as during preprocess‐
116 ing of a volume. The function should be declared:
117 void func(double frac, void *client_data);
118 frac An estimate of the fraction of the current operation that
120 is complete.
121 client_data
123 Pointer to the client data associated with the context.
124 The callback can be used to print a status report or to process
126 time-critical events such as user input. However, the callback
127 should not make any calls to VolPack functions since the inter‐
128 nal VolPack state may be inconsistent.
129 VP_LOG_ALLOC_FUNC
131 The func argument is a callback function that is called whenever
132 VolPack allocates memory. The function should be declared:
133 void func(void *ptr, int size, char *use,
134 int line, char *file, void *client_data);
135 ptr Address of the allocated memory.
137 size Size (in bytes) of the allocated memory.
139 use Short description of the use of the allocated memory.
141 line Source code line number for the call to the memory allo‐
143 cator.
144 file Source code file name for the call to the memory alloca‐
146 tor.
147 client_data
149 Pointer to the client data associated with the context.
150 The callback can be used to track memory allocations (primarily
152 for debugging memory leaks).
153 VP_LOG_FREE_FUNC
155 The func argument is a callback function that is called whenever
156 VolPack deallocates memory. The function should be declared:
157 void func(void *ptr, void *client_data)
158 ptr Address of the deallocated memory.
160 client_data
162 Pointer to the client data associated with the context.
163 The callback can be used to track memory deallocations (primar‐
165 ily for debugging memory leaks).
166 If the func argument is NULL then the corresponding callback function
168 is reset to the default behavior or disabled if there is no default
169 behavior.
170
172 The normal return value is VP_OK. The following error return value is
173 possible:
174 VPERROR_BAD_OPTION
176 The option argument is invalid.
177
179 VolPack(3), vpCreateContext(3), vpSetClientData(3), vpSetLookup‐
180 Shader(3), vpLoadRawVolume(3), vpStoreRawVolume(3)
181VolPack vpSetCallback(3)