Re: vga Screen Fader

 BBS: Inland Empire Archive
Date: 06-05-92 (06:05)             Number: 190
From: PHIL HODGES                  Refer#: NONE
  To: MICHAEL SKURKA                Recvd: NO  
Subj: Re: vga Screen Fader           Conf: (2) Quik_Bas

MS>In a message to Zack Jones <05-30-92 05:30> Phil Hodges wrote:

MS>PH>    Whoa...wait a sec!  I've been TRYING to figure out how
MS>PH> to do the equivalent of a screen fade in EGA, and the
MS>PH> results are either instantaneous color change, or too
MS>PH> "blinky."
MS> ...
MS>PH>    Do you know of a way to come CLOSE to fading in EGA?

MS>Not by changing palettes/colors, etc.  But a makeshift "fade" could be
MS>done by "spraying" the screen with black pixels!  I know it would be
MS>SUPER-SLOW in QB, but maybe Assembly would be tolerable.  I'm not

   Yes, that might work.  I've found a lot faster way to cycle through
colors.  Rather than drawing on an active page, then swapping pages
(which results in flickering), I found that using PCOPY results in no
flickering whatsoever, and is, indeed rather fast:

  Ap%=1:Vp%=0
  SCREEN 9,,Ap%,Vp%
  'draw stuff
  PCOPY Ap%,Vp%

  (I won't include the program I was experimenting with, since it's a
  little bit lengthy)

MS>good at graphics in Assembly (or really ANY language for that matter!
MS><grin>), but maybe someone around this echo could whip something up.
MS>It's a thought that just popped into my mind and I have NO idea of
MS>the complexity of the project.  It just sounded like a possibility
MS>that we could explore.  I know it's not a fade per se, but it may be
MS>the closest we can get with EGA.

   Well, an EGA adapter with 256K can use 64 colors assigned to 16
   attributes.  I wrote a little program so I could cycle through all 64
   colors (0-63, actually), and found that there were 15 shades of blue
   (counting turquoise, and grayish-blues), 8 shades of purple, 9 reds
   (including hot pink, pink, carnation)...brown, some yellows, several
   whites, orange..etc.  But they aren't close enough together to really
   look like fading.  I think your idea is probably good...it would look
   like Ultima VI, when you go through a moon gate (pixelates out).


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