[comp.sys.tandy] How to get 16 colors out of a TGA . . . ?

mdperry@boulder.colorado.edu (Marc D. Perry) (09/28/90)

I have a Tandy 1000TX which has the standard Tandy Graphics Adaptor.
Everything I have read implies (no, states) that the TGA can display
up to 16 different colors at simple resolution (is that 320 x 200, or
something?, I forget).  I have mine plugged into an Amdek RGB monitor
(circa 1985), and have only ever seen 8 colors; both in programs that
allow you to select the foreground/background colors, and in that
basic color program that comes in IBM-DOS.

Has anybody else experienced this (colors 9 thru 16 are just a repeat
of colors 1 thru 8)?

Is it because of the monitor (perhaps it is limited to only 8 colors,
or perhaps there is something I need to adjust--no apparent knobs to
turn)?

Is it because of the TGA?

Is there a program I can load on start-up?


Thanks,
mdp



Marc D. Perry                               (303) 492 8258                     
MCD Biology, Univ. of Colorado, Boulder, CO 80309-0347         
internet: mdperry@boulder.colorado.edu  

bobb@vice.ICO.TEK.COM (Bob Beauchaine) (09/28/90)

In article <27095@boulder.Colorado.EDU> mdperry@boulder.colorado.edu (Marc D. Perry) writes:
>I have a Tandy 1000TX which has the standard Tandy Graphics Adaptor.
>Everything I have read implies (no, states) that the TGA can display
>up to 16 different colors at simple resolution (is that 320 x 200, or
>something?, I forget).  I have mine plugged into an Amdek RGB monitor
>(circa 1985), and have only ever seen 8 colors; both in programs that
>allow you to select the foreground/background colors, and in that
>basic color program that comes in IBM-DOS.
>

  I have the same configuration as you, except my monitor is also a 
  Tandy.  I don't think your monitor is the problem; the monitor only
  displays the RGB signals from the graphics card, and I'm pretty sure
  any standard CGA monitor will suffice.

  The problem is software.  The 320x200,16 color mode is IBM video mode
  10 (I think, no reference on my desk).  This is a *graphics only* mode,
  first introduced on the PC Jr.  This mode is almost unused in
  commercial software, with one large exception : games.  You will see on
  most game packages a note claiming that the game supports Tandy graphics.
  This almost always means the game will display 16 colors.  From your 
  post, I think you are trying to get 16 colors in text mode.  
  
  This is
  possible on any standard CGA card, but requires you to manipulate the
  intensity/blink bit in one of the video ports.  You could do so from 
  the command line, but any program that resets the video mode will 
  probably only allow 8 colors again.

  Only one programming platform supports this video mode: BASIC.  None
  of the compilers from Microsoft or Borland have internal support for
  this mode (or the 640x200x4 colors mode, either). Very discouraging.

  Bob Beauchaine
  bobb@vice.ICO.TEK.COM

JRA102@psuvm.psu.edu (Jim Achuff) (09/28/90)

The TGA is actually a takeoff of IBM's PCjr. But anyway, colors 9-16 are simply
"high intensity" versions of colors 1-8. The age and condition of your monitor
may very well have somthing to do with your problem...I'd suggest a monitor
comparable to Tandy's CM-11 for the best results with TGA (or even an EGA
monitor would be great!)
I upgraded to EGA in my TX about a year ago, and like it, but I still dream
of having 1024x768x256 VGA...  8-)
Hope this helps...
-------
=\    Jim Achuff                   %%   Where is the victory?    \====
==\   JRA102@PSUVM.PSU.EDU       %%%%%% Where is the prize? When  \===
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====\ Student Consultant/Operator  %%   death finally dies? - PETRA \=

JAP131@psuvm.psu.edu (John Pelna) (09/28/90)

The TGA video mode does give you 16 colors, but they are only
displayed 8 at a time.  At least that's what my old manager
told me...  :-)

John
fav shack quote "batteries, batteries, everyone wants free batteries!"

fzsitvay@techbook.com (Frank Zsitvay) (09/30/90)

In article <5899@vice.ICO.TEK.COM> bobb@vice.ICO.TEK.COM (Bob Beauchaine) writes:
>In article <27095@boulder.Colorado.EDU> mdperry@boulder.colorado.edu (Marc D. Perry) writes:
>>I have a Tandy 1000TX which has the standard Tandy Graphics Adaptor.
>>Everything I have read implies (no, states) that the TGA can display
>>up to 16 different colors at simple resolution (is that 320 x 200, or
>>something?, I forget).  I have mine plugged into an Amdek RGB monitor
>>(circa 1985), and have only ever seen 8 colors; both in programs that
>>allow you to select the foreground/background colors, and in that
>>basic color program that comes in IBM-DOS.
>>
   on most cga type systems, the second 8 colors (9-16) are half-
intensity versions of the first 8 colors.   there is a good chance
that the amdek monitor does not support the intensity signal on
the card's rgb interface.  then again the tga board may not emulate
a cga board much, which makes cga information not applicable.

>
>  Only one programming platform supports this video mode: BASIC.  None
>  of the compilers from Microsoft or Borland have internal support for
          ^^^^^^^^^^^^^^^^^^^^^^^^
>  this mode (or the 640x200x4 colors mode, either). Very discouraging.


the microsoft basic compiler (version 7.0) supports modes
0 through 13.

-- 
fzsitvay@techbook.COM - one of these days i'll get it right...

Version 2 of anything is usually the version that works.