Oh no not again - ZEDRAGON II

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Andy Rea
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Re: Oh no not again - ZEDRAGON II

Post by Andy Rea » Sat Feb 03, 2018 9:51 pm

its bloody genius great work from nollkolltroll and the mighty SirMorris this certainly sets a high bar for anyone wanting to match let alone try and better it ! and for me the in game sound is a real boon. gah i feel guilty for sitting on my arse doing nothing....
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

sirmorris
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Re: Oh no not again - ZEDRAGON II

Post by sirmorris » Sat Feb 03, 2018 10:22 pm

Remember back on 13th September 2017 Andy? Someone wrote you a begging email that looked something like this:
Howdy!

I would like to write my sea dragon game on the zeddy and to do it I would like a custom display driver. I just can't get my head around the whole deal so if there's any help you could give me I'd really appreciate it.

I want as much processing time as possible so a reduced line count is on the cards. I'd like:

one line score
10 lines playfield
one line status

so 12 display lines in total.

The playfield lines however - well ideally they would be unterminated. No HALTs so each line shows a portion of a wider playfield, something like 1K characters wide. In a perfect world I'd have only one pointer to change and that would control the entire, window but if I had to change 10 pointers that wouldn't be the end of the world.

The score and status lines would be fixed, no scrolling.

Does that sound possible?

Charlie
Four days later after a couple of emails back and forth tightening up some details you sent me a lovely zip file including source for the completed display driver :ugeek: Couldn't have done it without you!

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Andy Rea
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Re: Oh no not again - ZEDRAGON II

Post by Andy Rea » Sat Feb 03, 2018 10:35 pm

its true... but look how far its come from whole character scrolling to this absolute master piece... you have taken a pigs ear and created a silken purse
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

sirmorris
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Re: Oh no not again - ZEDRAGON II

Post by sirmorris » Sat Feb 03, 2018 10:40 pm

Awwww geee ;)

This was the first version with sub - from an email to you on the 25th.

ZXp joystick to control it or shift+cursor keys. Bizarrely. Newline to start.
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ozedrag.p
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Andy Rea
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Re: Oh no not again - ZEDRAGON II

Post by Andy Rea » Sat Feb 03, 2018 10:54 pm

hehe i remeber that... was easy to get to the end :lol:

and we all ( well me, you and captain Moggy ) thought that was ace... little did we know then how slick it would turn out
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

nollkolltroll
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Re: Oh no not again - ZEDRAGON II

Post by nollkolltroll » Sun Feb 04, 2018 7:58 am

Ah, I was actually just this morning wondering about the display driver history. Great to get to know the story behind!

I guess it is good that Charlie has no idea about what can be done with display driver stuff, otherwise I bet nobody would have thought to try what Andy actually implemented. I am deeply impressed with what came about, a truly novel way of doing a text display. Intricate and just wonderful.
Releasing the source so I had the opportunity to actually understand what was done was crucial. It made me realise that the scrolling stuff I've been up to in demos would actually fit perfectly.
A few days later I had made a demo with smooth X- and Y-scrolling that I previewed to Charlie which responded "I wonder if a smooth scrolling seadragon would be possible. hmmm.". I of course replied YES, and we had a lot of mailing back and forth to get to the improved release of Zedragon II.

That's the story from my end.
/Adam

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Andy Rea
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Re: Oh no not again - ZEDRAGON II

Post by Andy Rea » Sun Feb 04, 2018 2:51 pm

Well the story started way back in 2011 ( i think ) over a beer 🍺 at a ferry terminaln somewhere in France waiting to come home from that years zx-team meet in germany, the seed was planted and many initial ideas rejected because of clock cycle constraints... Over the months that followed i had convinced myself several times it just wasn't possible to do what was required in the 207 cycles available, each attempt would be just a cycle or two over my allowance... I would walk away but a few weeks later new ideas would form and so this cycle of attempts and inevitable failures continued for months. For me the challenge is the enjoyable bit and largely explains why my programs are always functional rather that smartly polished and instruction usually none exsistant. Anyway I digress... Eventually I came up with the idea of using the stack as a sort of flow control mechanism and amazingly it worked... A demo was released SDEMO.P ( you can search for it on here ) and that was the last time the code was used, I had often thought about writing a full screen scrolling game but somehow never got round to it..... Then we arrive at September last year when I got the email from the mighty SirMorris i immediately knew this was an opportunity to reuse that code, just bolt on a bit more code for that top and bottom static lines jobs a good un , a couple of weeks later and it was all left to SirMorris to do the business. In steps Adam pulls apart the code works out the fairly complex flow through the routine, fully understand it ( amazing ) and then incredibly make it even better and infinitely more useful... I am in awe of you guys.

Anyway that's my story which probably would never have happens at all if it wasn't for that beer and the ideas bounced between myself and SirMorris that cold night

Regards Andy
6 x ZX81, 1 x TS1500 , 1 x +3e, 1 x timex 2040 printer, 1 x timex 2020 cassette deck, siclair printer and some spectrum

sirmorris
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Re: Oh no not again - ZEDRAGON II

Post by sirmorris » Sun Feb 04, 2018 7:41 pm

Lordy yes I'd forgotten about that! 4:30am ferries. Quite grim :D

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kmurta
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Re: Oh no not again - ZEDRAGON II

Post by kmurta » Sat Jun 23, 2018 7:54 pm

I can't load the game with the old ZXPAND, when trying it I get error 9.

Is ZEDRAGON compatible with the old ZXPAND?

I'm using EPROM 6.6 and firmware 2.62 Troll.

:?
1 x ZX81, 2 x TK85 , 1 TK82C, 1 TK95, 1 x Ringo R470, 1 x Alphacom 32 printer, 1 x ZXpand
ZeXtender board, Joy81 - Programmable Joystick Controller, Turbo Sound 81
http://zx81.eu5.org

Moggy
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Re: Oh no not again - ZEDRAGON II

Post by Moggy » Sat Jun 23, 2018 9:46 pm

kmurta wrote:
Sat Jun 23, 2018 7:54 pm
I can't load the game with the old ZXPAND, when trying it I get error 9.

Is ZEDRAGON compatible with the old ZXPAND?

I'm using EPROM 6.6 and firmware 2.62 Troll.

:?
Hi Kelly.

This is the bit that's missing! :D

https://www.sellmyretro.com/offer/detai ... pand-28480

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