From: Allan Schaffer (allan++at++southpark.engr.sgi.com)
Date: 06/19/2000 23:13:32
On Jun 19, 3:52pm, Kevin Kronmiller wrote:
> I have a terrain database in flight14.2 format. I used pfconv with no
> command modifiers to convert to pfb format (pfconv master.flt master.pfb).
> The increase in load speed is incredible but I find that the resulting pfb
> database is approximately 1/3 the size (in area not disk space). The 4
> degree by 4 degree flight database now measures slightly over 1x1 degree in
> size in pfb format. The original database is built in feet, not meters.
That sounds likely. Performer itself is completely units-unaware (a
value of 10.0 is simply evaluated as 10.0, it's not interpreted as
meters, feet, etc) _but_ the FLT format does contain a unit type,
which [looking at the source] the loader does appear to convert.
See: /usr/share/Performer/src/lib/libpfdb/libpfflt/README.FLT.R15_4.txt
[...]
- all database units are converted to meters by default. This can
be changed prior to each invokation of pfdLoadFile_flt() by calling
pfdConverterMode_flt( PFFLT_USEUNITS, new_units ) as desired.
See below for more details.
[...]
In /usr/include/Performer/pfdb/pfflt.h
/* loader modes */
#define PFFLT_USEUNITS 11
...
/* use units */
#define FLT_METERS 0
#define FLT_KILOMETERS 1
#define FLT_FEET 2
#define FLT_INCHES 3
#define FLT_NAUT_MILES 4
Good luck,
Allan
-- Allan Schaffer allan++at++sgi.com Silicon Graphics http://reality.sgi.com/allan
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