HDVIEW3.PRG
                          by Walt Sullivan

                           CIS: 76367,200
                        DELPHI: WALTSULLIVAN

HDVIEW3.PRG is a direct-from-disk animation viewer that plays ".DLT"
files created by programs in the CYBER series and others. It differs
from the ANIMATE?.PRG players in that it can display an animation of
any size. It does this by reading the delta information from a disk
file and displaying the animation 'on the fly'. Needless to say, it
can't approach the 30 frames per second speed of the RAM resident
players, but it can display that 900K animation that you slaved over
and then found out wouldn't fit in your 1040ST. It will show low rez
files if you are in low or medium rez and high rez files if you are 
in high rez.

HDVIEW3.PRG always operates in the Forward mode, i.e. frame #'last' 
is followed by frame #1. It also always operates in Double Buffered
mode. I found that there was no discernable speed difference between
single & double buffering, and the display didn't look as good in
single mode since you could see the 'wave' of screen updates proceed
down the screen. Other than those two exceptions, HDVIEW3 operates
in a similar way to the ANIMATE? programs. The Function keys control
the speed of display where F10 = full speed and F1 = 1.5 seconds per
frame. The SPACE bar pauses the display and any key resumes. The
HELP key brings up the file selector box, and the UNDO key takes you
back to the desktop. The file selector box show ".PI1" files when
you are in low or medium rez and ".PI3" file when in high. It should
catch incorrect rez files and selecting a "PI?" when there is no ".DLT"
file to go with it.

I would like to thank Tom Hudson for publishing the DLT file spec here
on Compuserve. And I also want to thank Dan Matejka for his article
"Al and C Routines..." in STart #1. I am a C programmer and not very
familiar with 68000 Assembly Language. In this article he discussed
longword memory_move and initialization routines in 68000 AL. I modified 
these routines to do a fast screen copy from a work area to the viewable
area and to erase the screen by init'ing it to zeros.

This program was developed with the Megamax C Development System on an
Atari 1040ST with color & monochrome monitors.