vpGetTimer(3)

💖 vpGetTimer(3) — Library Functions Manual 💖

okay bestie, gather round, because today we're talking about the interval timer facility in VolPack, and honestly? it's giving stopwatch energy. ⏱️✨

---

🎀 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;

(yes the double semicolon is real, it's canon, we do not touch it 💅)

---

🦋 ARGUMENTS 🦋

• vpc — the VolPack context, straight from vpCreateContext. your main character, your whole vibe.
• option — a constant that says which timer we're talking about. pick your fighter.
• iptr — the spot where the timer value gets stored. like, the lil jar we pour the number into. 🫙

---

✨ DESCRIPTION ✨

So these two functions are the performance measuring girlies of the VolPack library. they're how you find out how long stuff actually takes. but — and this is the important part — the library has to be compiled with a special flag first, otherwise this whole thing is not happening:

• -DHAVE_LORES_TIMER — for machines that support the gettimeofday C library call
• -DHAVE_HIRES_TIMER — for SGI machines that support high-resolution memory-mapped I/O timers; and on a Challenge or ONYX, you also have to specify -DHAVE_64BIT_TIMER

If one of those flags is given at compile time, then VolPack keeps a table recording the accumulated time spent in various operations. iconic. 👑

⚠️ but listen — some of the operations can only be timed with a high-resolution timer. if you compiled with a low-resolution timer, those time values will not be recorded and will just appear as zero. not a bug, just the rules. 💀

vpGetTimer retrieves the accumulated time for one particular operation. the option argument says which one:

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

and then — the moment you've been waiting for — the routine stores the accumulated time since the last call to vpClearTimer (or since the beginning of the program, if you never called it) into the location specified by iptr. 📝 the units are microseconds. tiny units, big feelings.

vpClearTimer just sets the specified timer value back to zero. reset era. 🧼✨

---

💀 ERRORS 💀

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

• VPERROR_BAD_OPTION — the option argument is invalid. you gave it a fake timer, bestie, and it noticed. 🙈

---

🔥 SEE ALSO 🔥

VolPack(3), vpCreateContext(3)

---

that's the whole page, no notes, you're gonna time everything and it's gonna slay. this was vpGetTimer(3) from VolPack, and that's the vibe check passed with flying colors 💖✨🦋🎀 — catch you in the next manpage, mwah. 💅