Search found 1076 matches

by Rich Talbot-Watkins
Fri Oct 20, 2017 1:47 pm
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 115
Views: 5965

Re: Starting a Prince of Persia port...

Nice work Kieran, it's really coming on well! Just to be clear, how is the sprite erasing currently working? Are you storing screen bytes before plotting the sprites, and then just copying them back over the top to erase? (i.e. a direct store, rather than the Exile type routine). I feel there must b...
by Rich Talbot-Watkins
Thu Oct 19, 2017 8:19 am
Forum: software: other
Topic: Double carriage return?
Replies: 12
Views: 250

Re: Double carriage return?

Well, this is the closest I can get: Screen.PNG Shift+Break the disc image to set up the stripey double-spaced mode, then LOAD "VATICAN" Note the line numbers have leading spaces as per normal, so this isn't exactly like the demo. I can only assume that was done with a custom VDU handler, ...
by Rich Talbot-Watkins
Wed Oct 18, 2017 4:13 pm
Forum: software: other
Topic: Double carriage return?
Replies: 12
Views: 250

Re: Double carriage return?

Well, one way to kind of do it is like this: MODE 6 VDU 19,0,4;0; ?&356=1 That adds the double spacing (basically makes the VDU drivers think that it's a 16k MODE with 640 bytes per character row), but don't let it scroll or it'll all go awry. But they're obviously doing something more sneaky th...
by Rich Talbot-Watkins
Wed Oct 18, 2017 12:23 pm
Forum: software: classic games
Topic: Exile
Replies: 37
Views: 2224

Re: Exile

I think it was definitely a 40/80 dual disk using that kind of technique. But it differed in having a total custom implementation of whatever OSFILE it is to load data. The catalog sector was deleted data in some higher track, and all the files were stored as deleted data with odd sector sizes, encr...
by Rich Talbot-Watkins
Wed Oct 18, 2017 11:24 am
Forum: software: classic games
Topic: Atic Atac: dodgy version in STH archive?
Replies: 38
Views: 6992

Re: Atic Atac: dodgy version in STH archive?

Rich, i didn't realize Nightshade only performed EOR operations on the data block. My bad, one of the first operations is an ADC, and then later there's a SBC. But what there isn't (unlike Alien8) is an EOR with the next byte of the encrypted block (EOR &E01,Y or equivalent). Not sure if that s...
by Rich Talbot-Watkins
Wed Oct 18, 2017 11:05 am
Forum: software: classic games
Topic: Exile
Replies: 37
Views: 2224

Re: Exile

Exile disk version had some pretty good protection as well (though, after the initial fairly trivial decrypter, it amounted to just putting some new filing system code in place via the vectors, after which you could simply *LOAD and *SAVE the files onto a clean disk!). I think the trickiness came wi...
by Rich Talbot-Watkins
Wed Oct 18, 2017 10:52 am
Forum: software: classic games
Topic: Atic Atac: dodgy version in STH archive?
Replies: 38
Views: 6992

Re: Atic Atac: dodgy version in STH archive?

Pernod wrote:The version I have doesn't contain the messages mentioned earlier in this thread, but it does have 'MJA OK' in the loader. Amazing how software circulated across the country pre-internet.

I started a thread about this a little while back, here!
by Rich Talbot-Watkins
Wed Oct 18, 2017 10:46 am
Forum: software: classic games
Topic: Atic Atac: dodgy version in STH archive?
Replies: 38
Views: 6992

Re: Atic Atac: dodgy version in STH archive?

So I'm still trying to fathom how Michael did it! Sounds like he did tackle each decoder one-by-one, as he peeled through the layers and found the disk formatter etc. So I'm wondering if there was some kind of loophole in the decryption system. Michael, it sounds a bit as if you zeroed the encoded b...
by Rich Talbot-Watkins
Wed Oct 18, 2017 7:56 am
Forum: software: classic games
Topic: Exile
Replies: 37
Views: 2224

Re: Exile

When I've heard of this in the past, the original developer has intervened, outing those complaining about the 'bugs' as a pirate.

e.g. Arkham Asylum from here:
http://www.cracked.com/article_19162_6- ... rates.html
by Rich Talbot-Watkins
Tue Oct 17, 2017 8:44 pm
Forum: software: classic games
Topic: Unusual tape loaders
Replies: 13
Views: 991

Re: Unusual tape loaders

Pro Boxing Simulator from Codemasters was a retitled re-release, which has the same loader! Edit: Ha, due to a bug in jsbeeb, it hangs once it's loaded. Oh well, try it in B-Em if you actually want to play it afterwards... Edit 2: Actually that's weird code. It's setting up the transmit baud rate, ...
by Rich Talbot-Watkins
Tue Oct 17, 2017 8:07 pm
Forum: software: classic games
Topic: Unusual tape loaders
Replies: 13
Views: 991

Re: Unusual tape loaders

Actually, By Fair Means Or Foul has an interesting tape loader. It also goes for the 'big block of data' approach, but it's broken into blocks too, and will prompt you to rewind the tape a small amount if it detects an error. The stream format is basically: * start of block marker * file number * bl...
by Rich Talbot-Watkins
Tue Oct 17, 2017 8:00 pm
Forum: software: classic games
Topic: Exile
Replies: 37
Views: 2224

Re: Exile

A good 20 years ago now, I worked on a game on the Playstation called Medievil. Sony had just introduced a library called Libcrypt, which took advantage of the fact that the Playstation hardware could read raw data from CDs, and that all releases were mastered with deliberately incorrect correction ...
by Rich Talbot-Watkins
Sat Oct 14, 2017 10:12 pm
Forum: software: classic games
Topic: "Unfixable bug" in BBC B Elite
Replies: 41
Views: 2011

Re: "Unfixable bug" in BBC B Elite

David Braben told me his idea presented to me as his idea, we coded it and took it in to Acornsoft, surprising and initally alarming them with the notion of a new scanner so late in production, or so I recall. Yes, that's the story that I've heard directly from Braben in the past; I was always unde...
by Rich Talbot-Watkins
Sat Oct 14, 2017 10:09 pm
Forum: software: classic games
Topic: "Unfixable bug" in BBC B Elite
Replies: 41
Views: 2011

Re: "Unfixable bug" in BBC B Elite

Thanks for joining the conversation, Ian! Nice to hear your memories and perspectives on BBC Elite, and many thanks for the hours and hours of fun I had playing Elite as a kid! Do you remember anything about the Star Clash row (alluded to upthread)? Was it ever demonstrated that any of your code was...
by Rich Talbot-Watkins
Sat Oct 07, 2017 3:31 pm
Forum: software: classic games
Topic: Atic Atac: dodgy version in STH archive?
Replies: 38
Views: 6992

Re: Atic Atac: dodgy version in STH archive?

Hey Michael, good to see you here again! :D I refer you to my post above :) Since you seem to be the only human being on the planet who cracked the Nightshade protection back in the day without a sophisticated hardware hack, I was wondering if you can still remember anything about how you did it? I ...
by Rich Talbot-Watkins
Thu Oct 05, 2017 10:44 am
Forum: software: classic games
Topic: Killer Gorilla for VideoNuLA (16 colours)
Replies: 13
Views: 467

Re: Killer Gorilla for VideoNuLA (16 colours)

Everything is plotted EOR but the foreground flag will avoid writing pixels where possible. It doesn't necessarily help distinguish between player sprites and background sprites, for instance, although I've not looked at the palette used for each object in detail. As far as I can see, moving object...
by Rich Talbot-Watkins
Thu Oct 05, 2017 9:40 am
Forum: software: classic games
Topic: Killer Gorilla for VideoNuLA (16 colours)
Replies: 13
Views: 467

Re: Killer Gorilla for VideoNuLA (16 colours)

I personally wouldn't go for earthy colours so that it looked like the C64 version. I'd prefer to diversify the range of hues, and maybe slightly subdue the super-saturated colours that the Beeb has by default, but still make it a colourful, slightly psychedelic world (more like a CPC game). But tha...
by Rich Talbot-Watkins
Thu Oct 05, 2017 7:02 am
Forum: software: classic games
Topic: Killer Gorilla for VideoNuLA (16 colours)
Replies: 13
Views: 467

Re: Killer Gorilla for VideoNuLA (16 colours)

Yeah Exile's a bit more complicated. For a start, it already uses all 16 colours: 0-7 are used for moving objects, and 8-15 for static scenery. The sprite routine uses the top bit of the colour to indicate whether a pixel is in the foreground (i.e. appears in front of objects). The graphics themselv...
by Rich Talbot-Watkins
Wed Oct 04, 2017 2:02 pm
Forum: bbcmicro.co.uk
Topic: Game categories
Replies: 19
Views: 445

Re: Game categories

Hats off to you for remembering it was me who first posted about it! (For curiosity, here's the only preserved reply to my original post :lol: )

Felt it was about time to give it another airing, I just needed an excuse :)
by Rich Talbot-Watkins
Wed Oct 04, 2017 1:20 pm
Forum: bbcmicro.co.uk
Topic: Game categories
Replies: 19
Views: 445

Re: Game categories

Crazy Balloon needs a new category: "hoax". Amongst various 'gems' in its BASIC listing: 290 REM On entering this subroutine 6502 procesor 'A','X' & 'Y' Registers should contain two's complement of the RAM used at compilation. 330 REM Copyright Acornsoft 340 REM BASIC program to be 350...
by Rich Talbot-Watkins
Tue Oct 03, 2017 5:40 pm
Forum: programming
Topic: Many DEFPROC, 1 ENDPROC?
Replies: 12
Views: 325

Re: Many DEFPROC, 1 ENDPROC?

In your example though, doesn't the "LOCAL flag" get processed in exactly the same way as the procedure parameter? I mean, I'd assume that procedure parameters break down internally as "LOCAL whatever: whatever = <value of passed parameter>". That's how I'd've implemented it anyw...
by Rich Talbot-Watkins
Tue Oct 03, 2017 1:50 pm
Forum: programming
Topic: Many DEFPROC, 1 ENDPROC?
Replies: 12
Views: 325

Re: Many DEFPROC, 1 ENDPROC?

I've been writing C and C++ for so long now that [...] Tell me: have you ever encountered Duff's Device ? (-8< Of course! But haven't had to do such low-level C hacking for many years now. Also, these days, with such huge advances in compilers and optimization techniques, I doubt if Duff's Device w...
by Rich Talbot-Watkins
Tue Oct 03, 2017 12:12 pm
Forum: programming
Topic: Many DEFPROC, 1 ENDPROC?
Replies: 12
Views: 325

Re: Many DEFPROC, 1 ENDPROC?

I've been writing C and C++ for so long now that this just looks like a monstrosity compared to: DEF PROC1:PROCa(1):ENDPROC DEF PROC2:PROCa(2):ENDPROC DEF PROC3:PROCa(3):ENDPROC DEF PROCa(flag) REM ... do something with flag ENDPROC The deeper call stack probably means it runs a bit slower, but rath...
by Rich Talbot-Watkins
Mon Oct 02, 2017 2:15 pm
Forum: general
Topic: Which games from other platforms did you wish was on the BBC?
Replies: 16
Views: 470

Re: Which games from other platforms did you wish was on the BBC?

I always longed for a proper version of Gauntlet, but could never really see how it would look nice on a Beeb, even if it could run at a decent speed. Between jerky scrolling, hi res / no colours, or chunky res with colours, it always seemed like an impossible task. That said, I've since imagined ho...
by Rich Talbot-Watkins
Fri Sep 29, 2017 3:33 pm
Forum: programming
Topic: Differences between BASIC1/2 and BASIC4 in handling an EVAL?
Replies: 20
Views: 371

Re: Differences between BASIC1/2 and BASIC4 in handling an EVAL?

BBC BASIC happily accepts both word and string indirectors as PROC/FN parameters, as you can see if you try this: 10DIM A% 255 20$A%="HELLO" 30PROCP("BYE") 40PRINT $A% 50END 60: 70DEF PROCP($A%) 80PRINT $A% 90ENDPROC >RUN BYE HELLO There's a bug which means that trying to do it w...
by Rich Talbot-Watkins
Fri Sep 29, 2017 2:30 pm
Forum: development tools
Topic: BASIC cruncher for PC
Replies: 22
Views: 615

Re: BASIC cruncher for PC

Don't use GOTO/GOSUBs instead of PROCs/FNs!!!! Please, for the love of humanity, please no!!!!

</melodramatic>

(Yes, it will potentially affect performance too: a cached PROC should be found more quickly than a GOTO a high line number. But also, parameter passing and all that!)
by Rich Talbot-Watkins
Fri Sep 29, 2017 10:56 am
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 115
Views: 5965

Re: Starting a Prince of Persia port...

Exile's sprite routine is ingenious isn't it? Using the stack as per-pixel scratch space is an idea I'd never thought of, and the fact that it makes recolouring, offsetting and mirroring the sprite so simple is brilliant in its inventiveness. If you can reserve those zp locations for holding the col...
by Rich Talbot-Watkins
Fri Sep 29, 2017 9:07 am
Forum: projects
Topic: Starting a Prince of Persia port...
Replies: 115
Views: 5965

Re: Starting a Prince of Persia port...

Great work Kieran, and so fast arriving at this point! Looks great... and I was able to navigate a few screens before it finally gave up.

How easy was it to transplant the Exile sprite routine by the way? It has some very specific needs regarding sprite format, screen dimensions, and ZP usage.
by Rich Talbot-Watkins
Fri Sep 29, 2017 8:11 am
Forum: development tools
Topic: BASIC cruncher for PC
Replies: 22
Views: 615

Re: BASIC cruncher for PC

Crunching is also a good way to slightly improve the performance of a BASIC program! When you get to shortening variable names, remember that variables are held in linked lists, one per start character. So for best performance, try to distribute the new names evenly across all start characters (e.g....
by Rich Talbot-Watkins
Fri Sep 29, 2017 7:10 am
Forum: programming
Topic: Differences between BASIC1/2 and BASIC4 in handling an EVAL?
Replies: 20
Views: 371

Re: Differences between BASIC1/2 and BASIC4 in handling an EVAL?

Just to add, I doubt it's anything to do with memory usage in the two machines. The main program is being loaded with PAGE at &1400, and doesn't appear to be using any strange memory locations. I'm 100% sure that it's not an emulation issue (jsbeeb passes all the 6502 test programs), so that lea...

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