5th11 - a quick made demo

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iss
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5th11 - a quick made demo

Post by iss » Wed Nov 06, 2019 2:29 am

Hello all!

This is a small simple demo devoted to yesterday: The Fifth of November ;).
v-2.png
TAP and DSK attached, enjoy!
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5th11.zip
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Symoon
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Re: 5th11 - a quick made demo

Post by Symoon » Wed Nov 06, 2019 9:42 pm

Hi ISS, what's nice with the demo is that it gives the impression that there are many Hires screens, but there are only really 3 different ones, right? (hence the possible TAP version)

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Re: 5th11 - a quick made demo

Post by trrerr » Wed Nov 06, 2019 10:03 pm

Great demo, ISS. Symoon I think the screens are more than 3.

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iss
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Re: 5th11 - a quick made demo

Post by iss » Wed Nov 06, 2019 10:37 pm

Thanks for the feedback!
And @Symoon, you spotted (again!) the most important detail of this demo - the used compression, anything else is already seen.
The demo has actually 6 "full-sized" pictures which are compressed with LZ4 and the result sizes are "dramatic" :).
Attached you can find original PNG's converted to RAW's 240x200 (i.e. 8000 bytes), LZ4's are the compressed binaries which were linked into main program. Runtime the images are unpacked directly to HIRES memory.
Although the pictures are not very complex the compression ration is good and the 6502 unpacker is fast!
For who is interested original packer/unpacker sources can be found here: https://github.com/fadden/fhpack
I've modified them quickly to make them Oric compatible. There is some more work like optimization and clean-up...
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Re: 5th11 - a quick made demo

Post by Symoon » Wed Nov 06, 2019 11:22 pm

Very interesting ^^
How big is the decoding loop? (you know why I'm asking :p)

I actually thought there were only 3 "black and white" pictures but one some of them you changed the colour attributes ;)

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Re: 5th11 - a quick made demo

Post by iss » Wed Nov 06, 2019 11:54 pm

Symoon wrote:
Wed Nov 06, 2019 11:22 pm
How big is the decoding loop? (you know why I'm asking :p)
The whole decoding is 198 bytes, but 4 bytes are local variables and there are some check which can be easily removed...

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Re: 5th11 - a quick made demo

Post by Symoon » Wed Nov 06, 2019 11:58 pm

iss wrote:
Wed Nov 06, 2019 11:54 pm
Symoon wrote:
Wed Nov 06, 2019 11:22 pm
How big is the decoding loop? (you know why I'm asking :p)
The whole decoding is 198 bytes, but 4 bytes are local variables and there are some check which can be easily removed...
Thanks.
Ah, that seems too big to match the 40 bytes-long challenge, unless with luck the 150 remaining bytes can be executed only once (hard to belive!).

But very interesting anyway!

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Re: 5th11 - a quick made demo

Post by coco.oric » Sun Nov 10, 2019 12:19 pm

My comment is common ; Great demo.

However, some improvements for next demos with music, scrolling ... why decoding pic is cutting scrolling ? is it possible to keep the scrolling during the lz4 operations ?
coco.oric as DidierV, CEO Member
Historic owner of Oric, Apple II, Atari ST, Amiga

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