Search found 159 matches

by joachim
Mon Dec 26, 2016 1:14 am
Forum: software: classic games
Topic: Try my XOR for PC
Replies: 10
Views: 2211

Re: Try my XOR for PC

davidb wrote:Lost Symbols might only be playable on RISC OS 3.1, and maybe also RISC OS 2.
Now that's a little too pessimistic. My go-to RISC OS platform is Linux running rpcemu running RISC OS 3.7, and it works fine on that.
by joachim
Sun Dec 25, 2016 6:29 pm
Forum: software: classic games
Topic: Try my XOR for PC
Replies: 10
Views: 2211

Re: Try my XOR for PC

I had been going to suggest that if you were planning to do for XOR the kind of thing you did with Repton Overture then you might look at Lost Symbols for inspiration: http://web.archive.org/web/20050324024443/http://www-solar.mcs.st-and.ac.uk/~davidb/Software/Lost/index.html But then I looked at th...
by joachim
Sat Dec 17, 2016 2:59 am
Forum: bbcmicro.co.uk
Topic: Yet more updates
Replies: 33
Views: 4945

Re: Yet more updates

From my recollection I had pretty bad results with the stairwaytohell.com images too: only one of them got as far as allowing me to play Level 1, and that one failed to load Level 2. Just checked the stairwaytohell.com images on jsbeeb again: Dunjunz.zip: Disc fault 18 at :2 00/00. This seems to be...
by joachim
Sat Dec 17, 2016 1:22 am
Forum: software: classic games
Topic: A XOR Project
Replies: 20
Views: 2805

Re: A XOR Project

You probably shouldn't take my word for it, but I believe the answers are yes, no, no. In other words, a bomb behaves exactly like a fish/chicken except when a fish/chicken/bomb lands on it. It doesn't explode in response to landing on a bomb or being exploded by an adjacent bomb or being hit by a d...
by joachim
Sat Dec 17, 2016 12:38 am
Forum: software: classic games
Topic: A XOR Project
Replies: 20
Views: 2805

Re: A XOR Project

Do you know about the XOR Resource Pages? http://www.danceswithferrets.org/xor/

In particular commentary on details of the rules (sounds like you've got them right though): http://www.danceswithferrets.org/xor/ve ... ne_xor.txt
by joachim
Sat Dec 17, 2016 12:07 am
Forum: bbcmicro.co.uk
Topic: Yet more updates
Replies: 33
Views: 4945

Re: Yet more updates

The bbcmicro.co.uk "Play" link for Dunjunz doesn't work for me: when I start the game, when it tries to load Level 1 I get "File not found at line 515 / Bad program". From my recollection I had pretty bad results with the stairwaytohell.com images too: only one of them got as far as allowing me to p...
by joachim
Sat Dec 03, 2016 10:49 pm
Forum: software: classic games
Topic: Dunjunz level 24 versions
Replies: 24
Views: 6772

Re: Dunjunz level 24 versions

Yes, there are two keys and two doors there. The second door will reappear even if the first one is opened, but you can walk through it or collect the second key and open it as well. This is presumably because the game clears the bit in the bitmap it uses to recorded which squares on the map are so...
by joachim
Sat Dec 03, 2016 10:05 pm
Forum: software: classic games
Topic: Dunjunz level 24 versions
Replies: 24
Views: 6772

Re: Dunjunz level 24 versions

I've updated my mapping tools a bit, though not really to take that feature into account. Key 13 at the bottom of the map sits on the same square as key 1, whose door does not appear on the level. :) Well, the level data says that door 1 is in the same place as door 13. Your level-reading code thro...
by joachim
Sat Dec 03, 2016 8:42 pm
Forum: software: classic games
Topic: Dunjunz level 24 versions
Replies: 24
Views: 6772

Re: Dunjunz level 24 versions

I'll have to play with the level data a bit and see what happens. I get the feeling that multiple collectable objects will not be supported - once the bit in the bitmap that seems to be for these kinds of items is set then there won't be a chance to collect a second or third item. Well, it turns ou...
by joachim
Wed Nov 30, 2016 10:23 pm
Forum: software: classic games
Topic: Dunjunz level 24 versions
Replies: 24
Views: 6772

Re: Dunjunz level 24 versions

Having seen that the level file format is significantly dependent on (object x, object y, object type) data rather than a simple array, I've started to wonder how well the game supports having multiple objects on the same square. Certainly you can create a few such cases by playing the unmodified ga...
by joachim
Wed Nov 30, 2016 1:08 am
Forum: software: classic games
Topic: Dunjunz level 24 versions
Replies: 24
Views: 6772

Re: Dunjunz level 24 versions

By the way, we shouldn't lose this previous thread which claims (haven't checked) to contain Dunjunz editing utilities.
by joachim
Wed Nov 30, 2016 12:37 am
Forum: software: classic games
Topic: Dunjunz level 24 versions
Replies: 24
Views: 6772

Re: Dunjunz level 24 versions

Nice work! Incidentally, I don't see the wall on level 1 that you referred to. Is that on the BBC version? You're right, the wall is on the BBC version and I misspoke. Since nobody on this thread has yet presented the two versions side by side, here's alex16cole's youtube playthrough reaching the bo...
by joachim
Tue Nov 29, 2016 3:19 am
Forum: software: classic games
Topic: Dunjunz level 24 versions
Replies: 24
Views: 6772

Re: Dunjunz level 24 versions

Ok, I got as far as extracting the level files from the BBC disk and Electron tape versions, stripping off the mild encryption and working out roughly how the levels are represented. It's hard to make out without a real map editing tool, but it looks as if levels 1, 2, 4, 5, 6, 8, 22 and 24 underwen...
by joachim
Fri Nov 25, 2016 2:41 am
Forum: software: classic games
Topic: Dunjunz level 24 versions
Replies: 24
Views: 6772

Dunjunz level 24 versions

Well, this is odd. The level 24 of Dunjunz whose difficulty alex16cole laments in his Youtube playthrough (https://www.youtube.com/watch?v=EGJUazFerMo) doesn't appear at all in Stuart Lewis's Dunjunz screenshot maps (http://www.stairwaytohell.com/gamehelp/MAP-Dunjunz-SL.html). Stuart's level 24 is j...
by joachim
Sun Nov 20, 2016 7:48 pm
Forum: software: classic games
Topic: Can anyone help me remember a game (with a loud siren noise)
Replies: 11
Views: 2465

Re: Can anyone help me remember a game (with a loud siren noise)

Just because it's a little tricky to find, here is where Mallory Manor has been posted: viewtopic.php?t=6289#p60076
by joachim
Sun Nov 20, 2016 5:44 pm
Forum: software: classic games
Topic: identify a book of game listings?
Replies: 3
Views: 2139

Re: identify a book of game listings?

ok, I was inspired by AbsoluteZero's thread to ask here. (Feel free to move this thread to a different subforum if more appropriate.) I'm trying to identify a book of BASIC game listings based on a recollection of one distinctive game. I don't even remember whether the book was BBC/Electron specifi...
by joachim
Thu Nov 17, 2016 11:56 pm
Forum: community projects
Topic: Electron User missing pages
Replies: 5
Views: 1483

Re: Electron User missing pages

It would be nice to submit these scans to archive.org too, since they have the same pages missing:

https://archive.org/stream/ElectronUser ... 9/mode/2up
by joachim
Mon Nov 14, 2016 12:04 am
Forum: software
Topic: archive submission ...
Replies: 1
Views: 611

Re: archive submission ...

... and one more from the same author (as if anybody needed another PD minesweeper-style game).
by joachim
Fri Oct 28, 2016 7:59 pm
Forum: software: classic games
Topic: Most under rated games
Replies: 16
Views: 2096

Re: Most under rated games

Rubble Trouble may be just a single-screen arcade game, but is very slick and playable and has great music, and the escalating difficulty levels and unique alternative play modes "Hayfield" and "Vanishing" keep it interesting even for experienced players without ever becoming stupidly impossible. Al...
by joachim
Sun Oct 16, 2016 2:01 am
Forum: general
Topic: Today I received.....
Replies: 5526
Views: 451701

Re: Today I received.....

"Now The Chips Are Down: The BBC Micro", Alison Gazzard (MIT Press, 2016), on clearance for $1 at the MIT Press Bookstore.

Just occasionally, living in the colonies works out well …
by joachim
Wed Oct 05, 2016 7:07 am
Forum: adventures
Topic: Twin Kingdom Valley
Replies: 21
Views: 4869

Re: Twin Kingdom Valley

Probably not directly related to what you're trying to do here, but for reference, this Pendragon column talks about patching bad save code in the Electron version of TKV: http://www.acornelectron.co.uk/mags/eu/ ... pen20.html
by joachim
Fri Sep 30, 2016 5:24 pm
Forum: software: other
Topic: Image2Mode7 - general image to teletext converter
Replies: 56
Views: 8456

Re: Image2Mode7 - general image to teletext converter

Nice! Is the alternating colour in the cat's sky part of a three-colour dither matrix, or did you do some error propagation? This is all with 4x4 Bayer matrix. 3x3 or even 2x2 might work better with the resolution limitations. Don't have time now (even to upload pics) but will post a patch over the ...
by joachim
Wed Sep 28, 2016 7:11 pm
Forum: software: other
Topic: Image2Mode7 - general image to teletext converter
Replies: 56
Views: 8456

Re: Image2Mode7 - general image to teletext converter

Cool stuff guys. I personally think the dithering adds a little extra definition overall. Would an ordered dither be better for something like this where the pixels are so large? Plus it might be better for video sequences, since ordered dither may create fewer deltas between frames. Jules's idea o...
by joachim
Tue Sep 27, 2016 4:47 pm
Forum: software: other
Topic: Image2Mode7 - general image to teletext converter
Replies: 56
Views: 8456

Re: Image2Mode7 - general image to teletext converter

Yes, agree with everything you've said although I would be prepared to try cutting that 2 bits per channel down to (log 3)/(log 2) bits — possible error values are {-1, 0, +1} — or even 1 bit — possible error values are {-½, +½}. The other thing I'd really want to try in making horizontal propagatio...
by joachim
Tue Sep 27, 2016 1:09 am
Forum: software: other
Topic: Image2Mode7 - general image to teletext converter
Replies: 56
Views: 8456

Re: Image2Mode7 - general image to teletext converter

Okay, having learnt from yesterday's dithering attempt, I set myself the significantly more modest task of only dithering within a character cell, and came up with a far simpler patch that doesn't have any of the problems of last time. I'm not quite sure whether I like the results, but they are most...
by joachim
Mon Sep 26, 2016 1:04 am
Forum: software: other
Topic: Image2Mode7 - general image to teletext converter
Replies: 56
Views: 8456

Re: Image2Mode7 - general image to teletext converter

Oh, and I realised I can't think of a way to do dithering properly as this normally relies on propagating the error from pixel-to-pixel but we don't strictly know which pixels will be which colour until we've searched all available combinations. Bit of a chicken & egg that one. Well now, I expected...
by joachim
Sun Sep 25, 2016 1:54 am
Forum: software: classic games
Topic: BBC Chess
Replies: 38
Views: 4679

Re: BBC Chess

The really interesting question is, how good a BBC chess program could we create today, by training a neural network using modern techniques on modern hardware? Since training one is a lot more computationally intensive than running it.
by joachim
Sat Sep 24, 2016 1:21 am
Forum: software: other
Topic: Image2Mode7 - general image to teletext converter
Replies: 56
Views: 8456

Re: Image2Mode7 - general image to teletext converter

You probably already realize this but even without changing the loss function, you can find a marginally better image (lower total error) by trying graphic chars other than the one that seems to be the best fit! I guess the advantage is that they result in a different hold char, and surprisingly tha...
by joachim
Fri Sep 23, 2016 8:05 pm
Forum: hardware
Topic: Slogger Pegasus 400 build and configuration log...
Replies: 34
Views: 3653

Re: Slogger Pegasus 400 build and configuration log...

And I wouldn't mind knowing what kind of mechanism the different filing systems used when accessing the additional memory provided on things like the Pegasus and AP3/4: some kind of paging, I guess, but where was the data exposed? Err, for the Peg, look here:- http://stardot.org.uk/forums/download/...
by joachim
Fri Sep 23, 2016 3:38 pm
Forum: software: other
Topic: Image2Mode7 - general image to teletext converter
Replies: 56
Views: 8456

Re: Image2Mode7 - general image to teletext converter

Just a thought, but would it be better to do the 3 bit colour quantization after the resize? This might preserve more image detail. Similarly perhaps dithering at the colour quantization step might retain more dynamic range. I noticed Julians via demo used dithering to a fairly decent effect is all...