---
name: "TracePixel"
section: "3"
platform: "linux"
package: "libvolpack1-dev"
version: "1.0b3-10"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/TracePixel"
---

# TracePixel(3)

print a trace of the voxels composited into a pixel

## NAME

vpTracePixel - print a trace of the voxels composited into a pixel

## SYNOPSIS

\#include \<volpack.h\>

vpResult

**vpTracePixel(***vpc, trace\_u, trace\_v***)**

-

  vpContext \**vpc;*

-

  int *trace\_u, trace\_v;*

## ARGUMENTS

- *vpc*

  VolPack context from **vpCreateContext.**

- *trace\_u, trace\_v*

  Intermediate image coordinates of the pixel to trace.

## DESCRIPTION

This routine is for debugging the rendering algorithms.  If *(trace\_u, trace\_v)* is a valid set of coordinates in the intermediate image then a printout appears during rendering showing a trace of all of the voxels that contribute to the pixel.  The intermediate image is not the same as the final image; see vpGetvpSetImage(3).

The VolPack library must be compiled with the -DDEBUG compiler option for this function to have any effect.

## SEE ALSO

[VolPack(3)](/VolPack/3.md)