pfuCalcVirtualClipTexParams(3pf)NAMEpfuCalcVirtualClipTexParams - calculate parameters for virtual clip
textures
FUNCTION SPECIFICATION
#include <Performer/pfutil.h>
void pfuCalcVirtualClipTexParams(int nLevels, int clipSize,
int invalidBorder, float minLODTexPix, float minLODLoaded,
float maxLODLoaded, float bboxMinDist, float bboxMaxDist,
float tradeoff, const struct pfVirtualClipTexLimits *limits,
int *return_LODOffset, int *return_numEffectiveLevels,
float *return_minLOD, float *return_maxLOD);
DESCRIPTIONpfuCalcVirtualClipTexParams attempts to calculate reasonable values for
the four parameters LODOffset, numEffectiveLevels, minLOD, maxLOD which
are need to be set per-frame or per-tile for virtual clip textures, given
as much information as the caller can provide about the geometry of the
scene or tile, the texture coordinate mapping, the current clip center of
the clip texture, and the current eyepoint.
For details on what the input parameters mean and a description of the
algorithm, see the commented source code in
/usr/share/Performer/src/lib/libpfutil/clipparams.C.
NOTES
ClipTexture functionality is not supported under Linux.
This function is specifically written to work around bugs and limitations
inherent in virtual clip texturing on InfiniteReality graphics. For a
description of these bugs and limitations, see
/usr/share/Performer/doc/clipmap/IRClipmapBugs.html or
/usr/share/Performer/doc/clipmap/IRClipmapBugs.txt. Because of this, the
behavior of this function is intricate; if it seems to be doing something
mystifying, you may have to trace through the commented source code to
see what it is thinking.
For examples of various uses of this function, see the sample source code
for the .spherepatch and .ct scene loaders, and the virtcliptex sample
program:
/usr/share/Performer/src/lib/libpfdb/libpfspherepatch/pfspherepatch.C
/usr/share/Performer/src/lib/libpfdb/libpfct/pfct.C
/usr/share/Performer/src/sample/pguide/libpf/C/virtcliptex.c
For a general description of how to do virtual clip texturing, see
/usr/share/Performer/doc/clipmap/HowToDoVirtual.html or
/usr/share/Performer/doc/clipmap/HowToDoVirtual.txt.
The libpfutil source code, object code and documentation are provided as
unsupported software. Routines are subject to change in future releases.
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pfuCalcVirtualClipTexParams(3pf)SEE ALSO
pfClipTexture, pfMPClipTexture, pfuCalcTexDerivs,
pfuCalcSizeFinestMipLOD, clipfly
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