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vlinit_fb
NAME
vlinit_fb - ParVox API initialization routine
for the frame buffers and output devices
SYNOPSIS
#include <parvox.h>
void vlinit_fb(vloutput_type device, int width,
int height,
int num_regions, char *filename,
int ifield, int hippi_num, int hippi_dev);
DESCRIPTION
vlinit_fb()
initializes the framebuffer and the appropriate data structures for
different output devices. It should be called after vlinit()
and before any other ParVox routines. It should also be called whenever
an output device type or the image size is changed. This routine
is implicitly called by vlread_environ().
If an environment file is pre-defined and loaded into the application program,
there is no need to call vlinit_fb() explicitly.
device
is of a enum type of possible values PPM, RLE, RAW_X, HIPPI_IOSC, HIPPI_PSITECH,
HIPPI_SGI, WAVELET, GZIP, RLEDIF. In ParVox 1.0, only PPM,
RAW_X, WAVELET and HIPPI_IOSC are supported: PPM is the only disk file
format currently supported. RAW_X and WAVELET are the output
types for the remote display by the xmparvox.
HIPPI_IOSC is the IOSC HiPPI framebuffer file format. width
and height
are the size of the output image. The image height will be rounded
to the nearest multiple of 32 for WAVELET output type due to the constraint
of the Wavelet compression algorithm. The IOSC HiPPI framebuffer
only supports two image sizes, 640x512 and 1280x1024. num_regions
is used for image space decomposition. It determines how many image
regions are destributed into each processor. The more regions
each processor has, potentially the better balance the load is, but the
more communication overhead it could be. Therefore, something between
3 to 5 is a good choice for num_regions. filename
is the prefix of the filename if PPM is chosen to be the output device.
The output file is put in output subdirectory under the current
working directory. If there is no output subdirectory, it
will be created. ifield, hippi_num,
and hippi_dev are only used for the
HIPPI_IOSC device. ifield
is the ifield number from the rendering computer to the HiPPI Framebuffer.
hippi_num and hippi_dev
represent the sender's hippi channel and logical ouput device number.
They are used to open the hippi device at the sender (Cray T3D or T3E)
side. The hippi device number is constructed as /dev/hippixx/oyy,
where xx is hippi_num and yy is hippi_dev.
SEE ALSO
vlinit,
vlread_environ
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