Search found 450 matches

by kieranhj
Thu Sep 14, 2017 9:51 am
Forum: software: other
Topic: VT100/ANSI terminal emulation via OSWRCH
Replies: 131
Views: 3658

Re: VT100/ANSI terminal emulation via OSWRCH

It's still the case that only the last few lines on that screenshot are "truthful" about their foreground/background colours, because that's down to the fundamental limit of only 8 colour pairs being available as described at length (if not necessarily clearly :-) ) in my post above - thi...
by kieranhj
Wed Sep 13, 2017 1:26 pm
Forum: software: other
Topic: VT100/ANSI terminal emulation via OSWRCH
Replies: 131
Views: 3658

Re: VT100/ANSI terminal emulation via OSWRCH

PS No rush, but do still you have that short test program? If so could you please post it over in the thread about emulator support for b-em (http://stardot.org.uk/forums/viewtopic.php?f=4&t=13464) before you lose it? I've posted a fix to the b-em implementation over on the thread, if you'd lik...
by kieranhj
Wed Sep 13, 2017 1:23 pm
Forum: emulators
Topic: Emulator support for VideoNuLA
Replies: 29
Views: 1198

Re: Emulator support for VideoNuLA

Try this: https://bitshifters.github.io/content/wip/b-em_170913.zip It seems to work OK now with your test program. The manual says "The rightmost pixel is always assumed to be zero/blank (the space between the characters)" so I was incorrectly interpreting this as always logical colour 0 ...
by kieranhj
Tue Sep 12, 2017 7:54 pm
Forum: upcoming and recent events & exhibitions
Topic: Retro Computer Festival - CCH, Cambridge - 16 & 17 September 2017
Replies: 28
Views: 985

Re: Retro Computer Festival - CCH, Cambridge - 16 & 17 September 2017

I'd completely forgotten about this due to RL (real life) getting in the way. I'd like to come along. Perhaps some Tricky/jbnbeeb/Retrosoftware gaming presence ? You'll need to check with Jason at CCH if they have any more space for actual tables / exhibits. It has been months since I spoke to him ...
by kieranhj
Tue Sep 12, 2017 10:13 am
Forum: emulators
Topic: Emulator support for VideoNuLA
Replies: 29
Views: 1198

Re: Emulator support for VideoNuLA

Steve reported a problem with the 3-bit attribute mode over in the VT100 thread. It seems that the rightmost pixel in every block is being set to black irrespective of how the original palette is setup at FE21. That's probably me misunderstanding the intended behaviour in 3-bit attribute modes from...
by kieranhj
Tue Sep 12, 2017 10:09 am
Forum: upcoming and recent events & exhibitions
Topic: Retro Computer Festival - CCH, Cambridge - 16 & 17 September 2017
Replies: 28
Views: 985

Re: Retro Computer Festival - CCH, Cambridge - 16 & 17 September 2017

I was planning to go but now can't make it. :( I have a double room booked (and paid for) at the Travelodge on Newmarket Road around the corner from the museum if anyone would like to make use of it?
by kieranhj
Mon Sep 11, 2017 12:38 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

Hmm yeah, the graphics data is pretty bulky! From my best understanding, the scenery tiles are an awkward size on the Apple (28x63), and are rendered in a complicated way. In particular, what intrigues me is the way the floors are rendered: That overlapping bit is a true horror! Given that the Appl...
by kieranhj
Fri Sep 08, 2017 3:41 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

My gut instinct on this is that the only bit which you can probably truly 'port' is the game/animation logic, basically all the high-level stuff. The graphics routines are going to need to get a total rewrite to conform more with the Beeb hardware. My take on it would be to bite the bullet and go t...
by kieranhj
Fri Sep 08, 2017 9:42 am
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

Lots of pondering going on at the moment. The more I think about it, the more the 7 pixels per byte format of the Apple II is a massive PITA. My current exploration is to convert the Apple II sprite data offline to MODE 4 (for now) screen format and store in column order for faster writing to the Be...
by kieranhj
Thu Sep 07, 2017 7:42 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

This evening's update. The good news is that I managed to get some player (Kid) sprites drawing, albeit hacking the plot function. :) The bad news is that he dies when he hits the floor! I'm not actually worried about this because it will just be some gameplay function I've not implemented yet which...
by kieranhj
Thu Sep 07, 2017 9:03 am
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

Nothing visual to show but this morning's commuter milestone was to get the MainLoop running without crashing or hitting a BRK! This has involved porting many collision detection functions relating to the player (and ignoring the guard and traps etc. for now.) Once I've got the animation sequence ta...
by kieranhj
Wed Sep 06, 2017 12:35 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

So I finally bit the SHADOW RAM bullet today and it turned out to be nowhere near as bad as I feared, mainly because PoP was so well written and carefully architected to use the 128K of banked memory on the Apple II in the first place. From the comments: *------------------------------- * * Notes: *...
by kieranhj
Tue Sep 05, 2017 12:56 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

Thanks for this, interesting stuff. I may be missing something, but can't you take comfort from the successful C64 port that you at least won't run out of ZP locations? I don't think the C64 port had two zero pages available. I guess the issue is perhaps that you're not able to throw the OS out as ...
by kieranhj
Mon Sep 04, 2017 9:18 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

So continuing the quest to move from plotting individual level screens to getting the real game code booted and the main loop running. Again, it turns out the Apple II had it's own crazy weird super low-level disc system and even then PoP didn't use the standard disc format but a special system crea...
by kieranhj
Mon Sep 04, 2017 8:48 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

Now seems a good a time as any to jump back to some more details about plotting Apple II sprite on a Beeb screen. I showed some of you my sprite plotting routine at ABug a while back which appears to work great but had one limitation - it only plotted on byte boundaries, so 8 pixels in MODE 4. The A...
by kieranhj
Mon Sep 04, 2017 8:14 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

After a week off work, and therefore the commute & programming time, I got back to looking at PoP today. It took a while to remember where I'd got up to but managed to make some small progress by the time I got home. The attached screenshot looks like the earlier one but with a couple of importa...
by kieranhj
Mon Sep 04, 2017 7:46 pm
Forum: hardware
Topic: NuLA demos
Replies: 74
Views: 2657

Re: NuLA demos

:shock: :-D =D> That looks amazing Rob, great work!

Gah, having moved house all my Beeb hardware (including the NULA package) are in boxes until I have time & space to get them set up again. Must do this at the weekend!!
by kieranhj
Thu Aug 31, 2017 6:01 pm
Forum: development tools
Topic: beebasm putbasic problem
Replies: 9
Views: 272

Re: beebasm putbasic problem

Im reminded that it would be great to get a BeebAsm repo going in the stardot team; it's such a useful tool and there's a number of useful patches around now. Indeed. And we never got to the bottom of the Teletextr bug when I was getting different behaviour at runtime whilst using a locally built b...
by kieranhj
Fri Aug 25, 2017 12:24 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

Another quick update for you folks. Find attached a new SSD that cycles through all 14 levels of the game and displays all the screens in each level. Or just hit this jsbeeb link: https://bitshifters.github.io/jsbeeb/?disc=https://bitshifters.github.io/content/wip/pop-beeb-plot-all-levels-mode4.ssd&...
by kieranhj
Fri Aug 25, 2017 11:59 am
Forum: software: other
Topic: not in the books : lda#&80:sta &fe30
Replies: 6
Views: 389

Re: not in the books : lda#&80:sta &fe30

See AllMem . Ahh, thank you - I was looking for a reference on Hazel: Pages &C0-&DF (192-223) - MOS ROM, Hazel workspace ================================================== &C000-&DBFF Sideways ROM workspace &DC00-&DCFF OSCLI string buffer &DD00-&DEFF Transient comman...
by kieranhj
Fri Aug 25, 2017 9:46 am
Forum: software: classic games
Topic: Galaforce 30th Anniversary Full Source code for BBC Micro
Replies: 15
Views: 1335

Re: Galaforce 30th Anniversary Full Source code for BBC Micro

leenew wrote:Wow!
What other treasures may be lurking on that hard drive Kevin? :shock:

Lee.

Apparently Crazee Rider, according to the Facebook post in the Acorn group at least...
by kieranhj
Fri Aug 18, 2017 10:21 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

In beebasm you can use braces {} to create blocks. Labels and variables are local to a block. You can even nest blocks. So you end up with something like this and the variable "loop" can be reused elsewhere: Indeed, and I do like it. But you can't promote labels outside of scope, for exam...
by kieranhj
Fri Aug 18, 2017 1:16 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

A word on jump tables. The Apple II source makes extensive use of jump tables as the interface between different code modules. Between EQ.S & GAMEEQ.S all of the jump tables are defined, that is all of the entry points to particular code module are given labels with consistent addresses: * Auxme...
by kieranhj
Fri Aug 18, 2017 12:57 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

My first goal was to get some of the plotting functions ported so I could draw a screen of a level. I identified a function "SURE" in the module FRAMEADV.S that is commented in the code as "Draw entire 10 x 3 screen from scratch". The process then is to move that module over to m...
by kieranhj
Fri Aug 18, 2017 12:35 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

Next step was to port across the two main header files from the Apple II source: EQ.S and GAMEEQ.S. Where "EQ" means "equates". These files contain the labels for every memory location in the code: zero page variables, local, global & game variables, code modules, jump tables...
by kieranhj
Fri Aug 18, 2017 12:23 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

OK, back to the start which was the simple sprite plot routine. The PoP sprite data is in a nice easy format and documented in the technical notes provided by Jordan available online. <byte> # images in file <address first image> - starting at &6000 <address second image> - etc. ... <address fir...
by kieranhj
Fri Aug 18, 2017 9:38 am
Forum: software: classic games
Topic: "Unfixable bug" in BBC B Elite
Replies: 32
Views: 1254

Re: "Unfixable bug" in BBC B Elite

jonb wrote:Me too, but most of all I am intrigued at what this bug actually is.

Whatever the Elite bug is, it must be very subtle, if it exists.

We could just ping David Braben on Twitter and ask him? I also have his Frontier email address through work.
by kieranhj
Fri Aug 18, 2017 9:28 am
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

Looking great Kieran. Well done. Always bowled over by your work! I've been reading the thread with interest and remember you showing your sprite plotting routine at Cambridge. As you progress, it'd be great to see a dev diary of sorts - I guess you're doing that now. I'd love to read about how you...
by kieranhj
Thu Aug 17, 2017 8:16 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 62
Views: 3304

Re: Starting a Prince of Persia port...

Finally, some visible progress to report! I have managed to port the level screen plotting code over to the Beeb and then attach my MODE 4 sprite plotting routine to it. This has been quite an epic journey so far, having ported about 9 of the 29 source modules (although not every function within) an...
by kieranhj
Thu Aug 17, 2017 1:53 pm
Forum: software: classic games
Topic: Games that were better on the Electron than on the Beeb?
Replies: 12
Views: 607

Re: Games that were better on the Electron than on the Beeb?

Definitely Frak! Better collision detection, more levels, a screen designer, customisable start level and colourschemes. It may only be monochrome (and monophonic) but it is a far, far better game than the BBC Micro version. I'd love a BBC Master version of Frak! that's the Electron version with BB...

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