Time for Zarch .... on the beeb?!

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trixster
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Time for Zarch .... on the beeb?!

Postby trixster » Tue Apr 17, 2018 1:46 pm

I was reading this thread about zarch on the speccy with interest:

viewtopic.php?f=1&t=5961&hilit=zarch+bbc

and wondered if anyone had had a serious thought about porting Zarch to the beeb? Now there are so many 2nd processor beebs / masters around thanks to the RPi, plus exciting stuff like the VideoNula, has anyone considered such a project? One for keiranhj? :wink:
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RobC
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Re: Time for Zarch .... on the beeb?!

Postby RobC » Tue Apr 17, 2018 1:54 pm

I thought about it for a while as I think you could do something reasonable with the Pi co-pro but came to the conclusion that it's a bit beyond me!

I'd have given it a go if I could have found code for a C version but I only ever found one in Blitz Basic and I have no experience in that.

However, I have got the Spectrum version of Virus working on the Beeb through my Spectrum emulator :D

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tricky
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Re: Time for Zarch .... on the beeb?!

Postby tricky » Tue Apr 17, 2018 6:00 pm

I think Gil had plans and maybe a demo for solid ground Zarch on the Speccy, but my memory seems to have missed a few refresh cycles!

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Kecske Bak
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Re: Time for Zarch .... on the beeb?!

Postby Kecske Bak » Tue Apr 17, 2018 7:07 pm

tricky wrote:I think Gil had plans and maybe a demo for solid ground Zarch on the Speccy, but my memory seems to have missed a few refresh cycles!
Was it Gil who wrote Repton 3 for the ZX Spectrum or did he just write Repton 1 and 2?

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tricky
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Re: Time for Zarch .... on the beeb?!

Postby tricky » Tue Apr 17, 2018 7:23 pm

Just 1 and 2, I think the beeb author did 3 themselves, but I think 1 & 2 may have been held back until 3 was ready.

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Pernod
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Re: Time for Zarch .... on the beeb?!

Postby Pernod » Tue Apr 17, 2018 8:15 pm

tricky wrote:Just 1 and 2, I think the beeb author did 3 themselves, but I think 1 & 2 may have been held back until 3 was ready.

It wasn't Matthew, just had a chat with him. Doesn't know who did either.
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Re: Time for Zarch .... on the beeb?!

Postby lurkio » Tue Apr 17, 2018 8:55 pm

trixster wrote:wondered if anyone had had a serious thought about porting Zarch to the beeb?

Already been done -- see Zander/Lurch:

:wink:

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Re: Time for Zarch .... on the beeb?!

Postby Kecske Bak » Wed Apr 18, 2018 3:50 am

tricky wrote:Just 1 and 2, I think the beeb author did 3 themselves, but I think 1 & 2 may have been held back until 3 was ready.

Thanks Tricky - always been interested in the Spectrum and Amstrad Repton 3s. I remember seeing the unreleased Amstrad version used the CPC equivalent of MODE 1 and that really fascinated me.

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danielj
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Re: Time for Zarch .... on the beeb?!

Postby danielj » Wed Apr 18, 2018 6:30 am

tricky wrote:I think Gil had plans and maybe a demo for solid ground Zarch on the Speccy, but my memory seems to have missed a few refresh cycles!


Virus was released on the speccy!

https://www.youtube.com/watch?v=DY8rBCplNWY

d.

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Re: Time for Zarch .... on the beeb?!

Postby Rocketeer » Wed Apr 18, 2018 7:51 am

Strangely enough I was thinking about this over Christmas and made a few preliminary notes about how it might look/work...

Split screen, mode 2 at the top, mode 1 at the bottom. Modified screen to give resolution of 256 x 192, two frame buffers of 12k each.

000 < display panel/height/fuel indicators >
024 < main play area >
191 < screen end >

The main rendering would happen on the second processor with data passed over to the host processor through the Tube. An intelligent erase of the hidden screen and update of the display panel/map would be done by the host processor.

Machine required to run: B/B+ with 16k SWR, BBC Master and 6502 second processor. Wire frame landscape for 3Mhz, filled for top speed Pi based machine.

Now I reckon, with a few tricks, there would need to be around 6k per frame passed to the host. Not having programmed the second processor before my question is how fast could this transfer could take place? Could it be as fast as 6/100 of a second? If it were we'd be looking at a quite reasonable 10fps for both versions when machine overheads are taken into account.

I'd have a crack at a proof of concept myself but I'm part way through a conversion I've been wanting to do for many years which I will reveal at a later date.