Lode Runner on the ZX81?

Any discussions related to the creation of new hardware or software for the ZX80 or ZX81
dr beep
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Lode Runner on the ZX81?

Post by dr beep » Sun Apr 30, 2017 9:49 pm

I want to cooperate with this.

https://zx81keyboardadventure.blogspot. ... esign.html

Not only do I have good compression methods available, I want to do it in lowres to save memory for levels.
I have an idea for the playermovement and "pixelperfect" digging of the stones.

The levels would look like shown, only player a bit different.

Lardo Boffin
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Re: Lode Runner on the ZX81?

Post by Lardo Boffin » Sun Apr 30, 2017 11:41 pm

That looks really interesting!
ZX80
ZX81 iss 1 (bugged ROM, kludge fix, normal, rebuilt)
Iss 3 ZXVid
TS 1000 iss 3, ZXPand AY, ZX8-CCB, ZX-KDLX & ChromaSCART
TS 1500
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Spectrum 16k (iss 1 s/n 1499)
Various Spectrum 48ks plus a DIVMMC future and SPECTRA

sirmorris
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Re: Lode Runner on the ZX81?

Post by sirmorris » Mon May 01, 2017 12:11 pm

This would be a massive gift for the 81 community! Good luck Dr. Beep!

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dasteph
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Re: Lode Runner on the ZX81?

Post by dasteph » Mon May 01, 2017 2:14 pm

Hi Dr Beep. Yes that's my page and musings on Lode Runner. Would be more than happy to have you on board the project. I've been a little distracted by other things (like ZXpand Mice) over the last month or so, so not had a lot of time on the project since that last post.

So yes, very keen to hear your ideas etc.

nollkolltroll
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Re: Lode Runner on the ZX81?

Post by nollkolltroll » Mon May 01, 2017 3:26 pm

This is a perfect game for the zeddy! Cheering you on from afar.
/Adam

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PokeMon
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Re: Lode Runner on the ZX81?

Post by PokeMon » Mon May 01, 2017 3:47 pm

Looks a bit like a Donkey Kong clone. :mrgreen:

dr beep
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Re: Lode Runner on the ZX81?

Post by dr beep » Mon May 01, 2017 8:28 pm

At the moment I am working on a compressionroutine in Excel/Open Office that builts a data-textfile with the compressed data to include in the source.

When the leveldata has an error it can be altered easily and rerun the compressionmacro.

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dasteph
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Re: Lode Runner on the ZX81?

Post by dasteph » Mon May 01, 2017 11:12 pm

The level compression really is one of the major keys to Lode Runner, being an entirely level driven game. Not cramming in enough was one of my concerns. I'd figured I'd need to make a least 10 levels available to make the game enjoyable and playable.

So, not going out on a limb here to say that the compression is a lot better than I outlined in the article. If's that's case could the be enlarged to the Spectrum's size, making full use of the screen without taking excessive space? Rather than the Apple ][s smaller level size, which I originally thought would be a good way to save bytes.

dr beep
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Re: Lode Runner on the ZX81?

Post by dr beep » Tue May 02, 2017 12:58 pm

dasteph wrote:
Mon May 01, 2017 11:12 pm
The level compression really is one of the major keys to Lode Runner, being an entirely level driven game. Not cramming in enough was one of my concerns. I'd figured I'd need to make a least 10 levels available to make the game enjoyable and playable.

So, not going out on a limb here to say that the compression is a lot better than I outlined in the article. If's that's case could the be enlarged to the Spectrum's size, making full use of the screen without taking excessive space? Rather than the Apple ][s smaller level size, which I originally thought would be a good way to save bytes.
For MUSHROOM ROOM I compressed 186 levels in app. 25K.
Not all full screen, but still...
http://www.worldofspectrum.org/infoseek ... id=0023117

dr beep
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Re: Lode Runner on the ZX81?

Post by dr beep » Tue May 02, 2017 7:33 pm

I did some research how to compress the levels.
1) player is only once, no compression needed
2) enemies are almost never placed where compression wins space
3) escapeladder also.

So when I handle player seperately and enemies and escapeladder as eachothers compressupplement
I have 7*2 values to identify character and repeater and 2 extra values for issue 2 and 3.
All values fit 4 bits so next 4 bits can be next character or number of repeats.

Single character is always stored in 4 bits, up to 18 characters in just 8 bits.
So a full screen 32x22 without compression (impossible) would fit in 352 bytes.
So 3 levels in 1K. If screen and program would need 6K then I still can load at least 30 levels.

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