Some tech demos now available

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Some tech demos now available

Postby Trixter » Wed Jul 24, 2013 8:12 pm

I recently programmed some tech demo graphics stuff for the PCjr; one is a demoscene demo with three simultaneous effects (two of them at the full 60Hz framerate), the other is a silly little game that displays full-screen 16-color video @ 30fps. Both of these use a 160x100x16 video mode I invented (quite by accident). More info, videos, and downloads here: http://trixter.oldskool.org/2013/07/20/ ... accidents/

If anyone has a burning desire to program 160x100x16 or do some of the other things shown in the programs, let me know and I can either post some code snippets or make some source available.
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Re: Some tech demos now available

Postby Eric » Wed Jul 24, 2013 9:20 pm

I've been wondering when you'd come by and talk about these!

Those demos of yours are going to be the first pieces of software I use to test my junior once I get my JrIDE!
(All this time I've had my PCjr, I really haven't had a way of getting software on it due to having only one 360kDSDD FDD and never being able to get it to run on anything other than the PCjr, e and the only commercial 360k disks I have are DOS and the introduction disk. ;P Which means the only thing I've done with Jr besides that and hardware mods is play with cartridge basic.

When I do, I'll be sure to upload a video of this as a response to yours!
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Re: Some tech demos now available

Postby Trixter » Thu Jul 25, 2013 10:37 am

I hope they aren't disappointing for you :-)

Before coding for the PCjr, I was working on a PC+CGA demo with some friends, and while that will still likely take precedence, I found that coding for the PCjr was not nearly as difficult as I thought it would be (assuming you have a 640K machine, anyway). I have a very strong desire to port a classic arcade game over to the Jr, although to be fair to other platforms I'll likely do it in 160x200 mode since that translates over very well to Tandy and CGA.
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Re: Some tech demos now available

Postby Trixter » Mon Aug 05, 2013 10:25 am

I'm giving more thought to making a PCjr arcade game. Are there any games you'd always wanted to play on PCjr with full graphics and sound but were never ported? (or ported improperly?)
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Re: Some tech demos now available

Postby Eric » Tue Aug 06, 2013 2:07 pm

One game I always thought would be cool to be ported to PCjr is the 2600 game, Yar's Revenge. I onow it's not exactly an arcade game and doesn't have the sexiest graphics to take advantage of the PCjr's hardware, but I haven't seen a PC port of it and it would go nicely with the PCjr joystick.

I'm sure there's a more suitable game out there for you project, but this was something I always just thought would be cool to see happen.
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Re: Some tech demos now available

Postby Trixter » Tue Aug 06, 2013 2:31 pm

It would be possible to port the gameplay 100% if it would be acceptable to only display a 160-line window, so that the entire screen could be moved up and down 40 lines for the qotile's "castle" movement without having to redraw the castle every time.

I was hoping for something a little more ambitious and period-appropriate, like a coin-op arcade game :) Some were ported very well (Burgertime with CGA composite 16-color graphics comes to mind); some were ported quite badly (Donkey Kong).

If you'd like to get your "Atari 2600 games ported to PCjr" fix, I recommend the cartridges of Pitfall II, River Raid, and Demon Attack -- all three are extremely faithful to the 2600 originals, and the first two use the "window movement" trick I mention above to seamlessly scroll the screen vertically without slowdown.
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Re: Some tech demos now available

Postby Eric » Wed Aug 07, 2013 4:16 am

Trixter wrote:I was hoping for something a little more ambitious and period-appropriate, like a coin-op arcade game :) Some were ported very well (Burgertime with CGA composite 16-color graphics comes to mind); some were ported quite badly (Donkey Kong).


I know exactly what you mean. Something thatwould demonstrate the PCjr's hardware capabilities while being really fun to play!


There's way too many PC ports that weren't done too well or done really well, but for the AT's 4 color CGA. It's been a bit difficult to think of a great arcade game that hasn't been ported at all... for me, at least.
That's probably just me, though. Someone's gonna think of something perfect and I'll be sitting here at my desk thinking "Gee! Why didn't I think about that!" or maybe I won't, but I do feel that I've been overthinking it because it feels like there is something perfect, but I just can think of what it is that I'm trying to think about right now.

C'mon, guys! Where you at? You can have this figured out in like... A SECOND! ;P

Okay, I'd better shut up.
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Re: Some tech demos now available

Postby Brutman » Wed Aug 07, 2013 4:00 pm

I'm getting ready to move the family and household possessions 1800 miles across the country. I'm a little preoccupied. ; - 0
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Re: Some tech demos now available

Postby Eric » Wed Aug 07, 2013 7:05 pm

Brutman wrote:I'm getting ready to move the family and household possessions 1800 miles across the country. I'm a little preoccupied. ; - 0

I know! I was just being a rude jerk. Anyway, good luck with that. I hope the move goes smoothly and is a pleasant experience, and more importantly, the actual experience of living there, too.
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