NAME

vpGetTimer, vpClearTimer - interval timer facility

SYNOPSIS

#include <volpack.h>

vpResult

vpGetTimer(vpc, option, iptr)

: vpContext *vpc;
: int option;
: int *iptr;;

vpResult

vpClearTimer(vpc, option)

: vpContext *vpc;
: int option;

ARGUMENTS

vpc: VolPack context from vpCreateContext.
option: Constant that specifies a particular timer.
iptr: Location for storing the timer value.

DESCRIPTION

These functions are used for measuring the performance of the VolPack library. To use them, the library must be compiled with a special flag: either -DHAVE_LORES_TIMER (for machine that support the gettimeofday C library call) or -DHAVE_HIRES_TIMER (for SGI machines that support high-resolution memory-mapped I/O timers; on a Challenge or ONYX, the -DHAVE_64BIT_TIMER must also be specified). If one of these flags is specified at compile time then VolPack maintains a table recording the accumulated time spent in various operations. Note that some of the operations can only be timed with a high-resolution timer; time values will not be recorded and will appear to be zero if a low resolution timer is specified at compile time.

vpGetTimer retrieves the accumulated time for a particular operation. The option argument specifies which operation:

VPTIMER_SHADE: Time the routine that computes the contents of the shading lookup table.
VPTIMER_RENDER: Time the routine that renders a volume (includes VPTIMER_CLSFY_OCTREE, VPTIMER_COMPOSITE, VPTIMER_DEPTHCUE, and VPTIMER_WARP).
VPTIMER_COMPOSITE: Time the routine that computes the intermediate image from the volume (includes VPTIMER_CLEAR, VPTIMER_TRAVERSE_OCTREE, VPTIMER_ERT, VPTIMER_TRAVERSE_RUNS, and VPTIMER_PROCESS_VOXELS).
VPTIMER_DEPTHCUE: Time the routine that performs the depth cueing fixup on the intermediate image.
VPTIMER_WARP: Time the routine that warps the intermediate image into the final image.
VPTIMER_TRAVERSE_RUNS: Time the portion of the compositing routine devoted to traversing the volume data structures.
VPTIMER_PROCESS_VOXELS: Time the portion of the compositing routine devoted to compositing voxels into the intermediate image.
VPTIMER_ERT: Time the early-ray termination checks during compositing.
VPTIMER_CLSFY_OCTREE: Time the octree classification stage.
VPTIMER_TRAVERSE_OCTREE: Time the portion of the compositing routine devoted to traversing the octree.
VPTIMER_CLEAR: Time the routine that clears the intermediate image at the beginning of compositing.

The routine stores the accumulated time since the last call to vpClearTimer (or since the beginning of the program) in the location specified by iptr. The units of the value are microseconds.

vpClearTimer sets the specified timer value back to zero.

ERRORS

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

VPERROR_BAD_OPTION: The option argument is invalid.

NAME

SYNOPSIS

ARGUMENTS

DESCRIPTION

ERRORS

SEE ALSO