1vpGetTimer(3)              Library Functions Manual              vpGetTimer(3)
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NAME

6       vpGetTimer, vpClearTimer - interval timer facility
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SYNOPSIS

9       #include <volpack.h>
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11       vpResult
12       vpGetTimer(vpc, option, iptr)
13           vpContext *vpc;
14           int option;
15           int *iptr;;
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17       vpResult
18       vpClearTimer(vpc, option)
19           vpContext *vpc;
20           int option;
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ARGUMENTS

23       vpc    VolPack context from vpCreateContext.
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25       option Constant that specifies a particular timer.
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27       iptr   Location for storing the timer value.
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DESCRIPTION

30       These  functions  are used for measuring the performance of the VolPack
31       library.  To use them, the library must  be  compiled  with  a  special
32       flag:  either -DHAVE_LORES_TIMER (for machine that support the gettime‐
33       ofday C library call) or -DHAVE_HIRES_TIMER (for SGI machines that sup‐
34       port  high-resolution memory-mapped I/O timers; on a Challenge or ONYX,
35       the -DHAVE_64BIT_TIMER must also be specified).  If one of these  flags
36       is  specified  at compile time then VolPack maintains a table recording
37       the accumulated time spent in various operations.  Note  that  some  of
38       the  operations  can  only  be timed with a high-resolution timer; time
39       values will not be recorded and will appear to be zero if a low resolu‐
40       tion timer is specified at compile time.
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42       vpGetTimer  retrieves  the accumulated time for a particular operation.
43       The option argument specifies which operation:
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45       VPTIMER_SHADE
46              Time the routine that  computes  the  contents  of  the  shading
47              lookup table.
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49       VPTIMER_RENDER
50              Time   the   routine  that  renders  a  volume  (includes  VPTI‐
51              MER_CLSFY_OCTREE, VPTIMER_COMPOSITE, VPTIMER_DEPTHCUE, and VPTI‐
52              MER_WARP).
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54       VPTIMER_COMPOSITE
55              Time  the  routine that computes the intermediate image from the
56              volume (includes VPTIMER_CLEAR,  VPTIMER_TRAVERSE_OCTREE,  VPTI‐
57              MER_ERT, VPTIMER_TRAVERSE_RUNS, and VPTIMER_PROCESS_VOXELS).
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59       VPTIMER_DEPTHCUE
60              Time  the  routine  that  performs the depth cueing fixup on the
61              intermediate image.
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63       VPTIMER_WARP
64              Time the routine that warps  the  intermediate  image  into  the
65              final image.
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67       VPTIMER_TRAVERSE_RUNS
68              Time  the portion of the compositing routine devoted to travers‐
69              ing the volume data structures.
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71       VPTIMER_PROCESS_VOXELS
72              Time the portion of the compositing routine devoted to composit‐
73              ing voxels into the intermediate image.
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75       VPTIMER_ERT
76              Time the early-ray termination checks during compositing.
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78       VPTIMER_CLSFY_OCTREE
79              Time the octree classification stage.
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81       VPTIMER_TRAVERSE_OCTREE
82              Time  the portion of the compositing routine devoted to travers‐
83              ing the octree.
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85       VPTIMER_CLEAR
86              Time the routine that  clears  the  intermediate  image  at  the
87              beginning of compositing.
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89       The  routine  stores  the  accumulated  time  since  the  last  call to
90       vpClearTimer (or since the beginning of the program)  in  the  location
91       specified by iptr.  The units of the value are microseconds.
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93       vpClearTimer sets the specified timer value back to zero.
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ERRORS

96       The  normal return value is VP_OK.  The following error return value is
97       possible:
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99       VPERROR_BAD_OPTION
100              The option argument is invalid.
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SEE ALSO

103       VolPack(3), vpCreateContext(3)
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107VolPack                                                          vpGetTimer(3)
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