Search found 920 matches

by kieranhj
Wed Jul 29, 2020 4:55 pm
Forum: new projects and releases: demoscene
Topic: Thousands of colours (Acorn Electron)
Replies: 6
Views: 535

Re: Thousands of colours (Acorn Electron)

Nice! Although I'm never fan of flickering colours at 50Hz. I'm wondering though, would it perhaps be possible to make an effect similar to the 2-colour plasma from Twisted Brain?
by kieranhj
Wed Jul 22, 2020 11:27 pm
Forum: development tools
Topic: Looking for a <modern image format> to bitmap tool (python, preferably)
Replies: 4
Views: 325

Re: Looking for a <modern image format> to bitmap tool (python, preferably)

Thanks. That would still be really useful actually as you’d end up with a PNG just containing the correct 256 colours for MODE 13. It would be easy to extend the above Python script to output the correct byte encoding for loading directly into MODE 13 screen buffer. I don’t really want to be reinven...
by kieranhj
Wed Jul 22, 2020 11:12 pm
Forum: the complete BBC games archive
Topic: Disassembly problem
Replies: 11
Views: 1193

Re: Disassembly problem

Yeah the library is a bit busted. That’s been filed as a bug, along with some others, on GitHub: https://github.com/shawty/BBCB_DFS_Catalog/issues/3
by kieranhj
Wed Jul 22, 2020 11:09 pm
Forum: development tools
Topic: Looking for a <modern image format> to bitmap tool (python, preferably)
Replies: 4
Views: 325

Re: Looking for a <modern image format> to bitmap tool (python, preferably)

I’ve got a png2arc Python script but it only works for MODE 9 and requires input PNG images with <= 16 colours. It does spit out a separate 64 byte file with the colour palette values at least. https://github.com/kieranhj/stniccc-archie/blob/master/bin/png2arc.py It’s been on my list to do a MODE 13...
by kieranhj
Sun Jul 19, 2020 10:38 am
Forum: programming
Topic: Timing of code (Risc OS)
Replies: 3
Views: 408

Re: Timing of code (Risc OS)

Coming from the Beeb I always forget the Archie has a border. I will borrow this idea for raster timing!
by kieranhj
Sat Jul 18, 2020 10:15 pm
Forum: introduce yourself
Topic: Hello from Oslo
Replies: 14
Views: 596

Re: Hello from Oslo

Welcome to the forum Tor! Any new Archimedes demos in the offing maybe? There’s been a small resurgence of late... :D
by kieranhj
Fri Jul 17, 2020 7:04 pm
Forum: past all-day virtual ABugs
Topic: All-day 'Virtual' Acorn session #6, Saturday 1st August 2020, 9am - 11pm [NOW FULL!]
Replies: 105
Views: 5181

Re: All-day 'Virtual' Acorn session #6, Saturday 1st August 2020, 9am - 11pm

I’d like to attend this session please! I should be around for the afternoon and evening. Thanks again for organising.
by kieranhj
Fri Jul 17, 2020 9:32 am
Forum: programming
Topic: Big machine code programs
Replies: 14
Views: 765

Re: Big machine code programs

The thought of trying to build a massive program like POP on a real BBC Micro brings me out in a sweat. :shock:
by kieranhj
Wed Jul 15, 2020 9:34 pm
Forum: bitshifters (new bbc master games)
Topic: Prince of Persia
Replies: 167
Views: 18575

Re: Prince of Persia

Well it seems like I can hardly let the POP fans down now, can I? This is a Release Candidate for version 1.2 that hopefully works with MOS 3.5 and Master Compact. I hesitate to call it a fix, more a massive hack :? so any testing on real hardware would be gratefully received before I update the off...
by kieranhj
Fri Jul 03, 2020 1:28 pm
Forum: bitshifters (new bbc master games)
Topic: Prince of Persia
Replies: 167
Views: 18575

Re: Prince of Persia

(I'd be mildly interested to know what 3.5 has that's needed by Prince of Persia - I suppose I'm mildly surprised that a game has much to do with the OS. I'm sure it all makes sense, to those in the know.) I suspect it’s probably some area of extended RAM that I’m abusing without permission and can...
by kieranhj
Fri Jul 03, 2020 1:26 pm
Forum: bitshifters (new bbc master games)
Topic: Prince of Persia
Replies: 167
Views: 18575

Re: Prince of Persia

A Master 128 without MOS3.2 is a recipe for madness.

I never did get to bottom of why POP doesn’t like 3.5. Mostly because I couldn’t work out how to get a configuration of a Master Compact but with DFS in an emulator. #-o
by kieranhj
Wed Jul 01, 2020 10:03 am
Forum: 32-bit acorn software: other
Topic: Modern development environment for Archimedes
Replies: 4
Views: 1195

Re: Modern development environment for Archimedes

Just a quick update on this, I decided rather belatedly to just contact the author of vasm to report the bugs. Lo & behold he fixed them all in less than 24 hours. #-o I wish I had done this sooner. There hasn't been a new official release of 1.8i yet but you can grab the nightly sources with all kn...
by kieranhj
Wed Jun 24, 2020 8:17 am
Forum: 8-bit acorn hardware
Topic: 8271 disc controller de-cap and craziness -- do not try this at home!
Replies: 442
Views: 14796

Re: 8271 disc controller craziness -- do not try this at home!

Great blog post Chris, a really interesting read. Thank you.

I guess even Kevin Edwards’ tape copy protection system decided that would have been step of evil too far!!
by kieranhj
Mon Jun 22, 2020 8:42 pm
Forum: new projects and releases: demoscene
Topic: New demo - Reach
Replies: 9
Views: 1294

Re: New demo - Reach

It’s a fab demo. Makes me wish I had an ARM3 machine, or a mega overclocked ARM250!!
by kieranhj
Thu Jun 11, 2020 10:30 pm
Forum: new ideas wishlist & general chat
Topic: Atari 2600 games
Replies: 13
Views: 700

Re: Atari 2600 games

Atari 2600 is a wonderful but highly idiosyncratic machine. Even though it runs just over 1MHz 6502 and has apparently low resolution, there are many aspects of the hardware that are very difficult to translate to the Beeb’s architecture and bitmap screen, not least the 128 colour palette! I think s...
by kieranhj
Wed Jun 03, 2020 8:32 am
Forum: new projects and releases: demoscene
Topic: NOVA Online Invite - a new Bitshifters demo for the BBC Master
Replies: 10
Views: 827

Re: NOVA Online Invite - a new Bitshifters demo for the BBC Master

I have just had a very quick look at this... it's incredible! I think its possibly your best demo yet. I did find what I think is a bug in the BASIC loader though. It wouldn't run on my Compact because it is looking for host types 3 (Master) or 6 (Archimedes). When I changed 6 to 5 it worked perfec...
by kieranhj
Tue Jun 02, 2020 1:31 pm
Forum: programming
Topic: VDU-stream 'sprites'
Replies: 16
Views: 1145

Re: VDU-stream 'sprites'

This is actually quite a cute optimisation challenge. A naive approach for 'sprites' might PLOT individual points in each colour but then you're only going to get 255/6 ~= 42 pixels maximum, not enough for an 8x8 sprite, and doesn't even account for selecting colours with GCOL etc. Instead you'd hav...
by kieranhj
Tue Jun 02, 2020 11:25 am
Forum: programming
Topic: "Legally" writing to the screen
Replies: 17
Views: 1131

Re: "Legally" writing to the screen

I asked the question because I'm writing a program that displays multi-coloured graphics/tiles/sprites to the screen and Acorn put such an emphasis on following the guidelines and doing things legally. One of the main arguments being that such well-written programs would work on a second processor....
by kieranhj
Mon Jun 01, 2020 8:06 pm
Forum: programming
Topic: "Legally" writing to the screen
Replies: 17
Views: 1131

Re: "Legally" writing to the screen

If you're only really interested in sprites/tiles of a limited variety of sizes, you could have a different VDU code and routine for each one. E.g. VDU &F1 could indicate that you're about to plot an 8x8 sprite, VDU &F2 for a 16 x 8 etc. Your custom handler would then read the screen offset and spr...
by kieranhj
Mon Jun 01, 2020 12:24 pm
Forum: 8-bit acorn software: other
Topic: Any condensed font, say 6px wide?
Replies: 12
Views: 935

Re: Any condensed font, say 6px wide?

Dethmunk also made me a small MODE 2 proportional font for Prince of Persia. The glyphs are 2/4/6 pixels wide, so 1/2/3 bytes wide in MODE 2, which is quite convenient.
by kieranhj
Sun May 31, 2020 11:39 pm
Forum: 8-bit acorn software: other
Topic: Any condensed font, say 6px wide?
Replies: 12
Views: 935

Re: Any condensed font, say 6px wide?

Much to my surprise on discovering the code, but Stunt Car Racer plots a 7-pixel wide font to squeeze a bit more out of the available screen real-estate.
by kieranhj
Thu May 28, 2020 11:41 pm
Forum: programming
Topic: "Legally" writing to the screen
Replies: 17
Views: 1131

Re: "Legally" writing to the screen

If you want to do anything interesting, then the short answer is: no!

The long answer is that Acorn didn’t think / care about sprites, so you’re limited to standard PLOT calls I’m afraid.
by kieranhj
Thu May 28, 2020 12:48 pm
Forum: new projects and releases: demoscene
Topic: NOVA Online Invite - a new Bitshifters demo for the BBC Master
Replies: 10
Views: 827

Re: NOVA Online Invite - a new Bitshifters demo for the BBC Master

The most important part of the fire alarm story is that nobody noticed for about 10 minutes during the DJ set. :D

I'm glad you all like the demo, it was a lot of fun to make!
by kieranhj
Thu May 28, 2020 12:46 pm
Forum: past all-day virtual ABugs
Topic: All-day 'Virtual' Acorn session #4, Saturday 6th June 2020, 9am - 10pm - NOW FULL
Replies: 119
Views: 7112

Re: All-day 'Virtual' Acorn session #4, Saturday 6th June 2020, 9am - 10pm

What an amazing line up of talks! Thanks for organising and for all the speakers taking the time. Looking forward to it. :)
by kieranhj
Wed May 27, 2020 7:12 pm
Forum: past all-day virtual ABugs
Topic: All-day 'Virtual' Acorn session #4, Saturday 6th June 2020, 9am - 10pm - NOW FULL
Replies: 119
Views: 7112

Re: All-day 'Virtual' Acorn session #4, Saturday 6th June 2020, 9am - 10pm

Oooh, looking at the talks being lined up, I would like to attend this one please!
by kieranhj
Wed May 27, 2020 5:34 pm
Forum: programming
Topic: Incrementing a 2-byte number
Replies: 14
Views: 876

Re: Incrementing a 2-byte number

I'll raise you this code : INC &70 ; 5c BEQ inchigh ; 2/3c BNE skip1 ;3c .skip1 BNE done ;3c .inchigh INC &71 ; 5c .done ; constant time ; 13c ; total ; 10 bytes if I have my maths right =D> Very nice! There's always another cycle to be squeezed when you need it most. [-o<
by kieranhj
Wed May 27, 2020 2:06 pm
Forum: programming
Topic: Incrementing a 2-byte number
Replies: 14
Views: 876

Re: Incrementing a 2-byte number

The more masochistic cycle-counter might do... INC &70 ; 5c BNE skiphigh ; not taken ; 2c INC &71 ; 5c BNE done ; 3c (unlikely to be incrementing &FFFF or use BRA) .skiphigh ; branch taken ; 3c NOP ; 2c NOP ; 2c BNE done ; 3c (unlikely to be incrementing &FFFF or use BRA) .done ; constant time ; 15c...
by kieranhj
Tue May 26, 2020 10:47 pm
Forum: new projects and releases: demoscene
Topic: NOVA Online Invite - a new Bitshifters demo for the BBC Master
Replies: 10
Views: 827

NOVA Online Invite - a new Bitshifters demo for the BBC Master

Hello all. Another day, another demo? We are spoiling you at the moment, it seems. :D The NOVA demoparty is going online this year, due to Coronavirus, so we thought we'd make an invitation to let everyone know about it. It's quite different in style from the BEEB-NICCC demo, but we hope you enjoy i...
by kieranhj
Tue May 26, 2020 9:51 pm
Forum: 8-bit acorn software: classic games
Topic: Elite BeebAsm Source
Replies: 21
Views: 3487

Re: Elite BeebAsm Source

This is a bit of an old thread, but if anyone is interested, I've gone through and added Paul Brink's comments to Kieran's Elite BeebAsm source. I've submitted them in a pull request at https://github.com/kieranhj/elite-beebasm/pull/4 I'm hoping to use this as a base for creating a version of the E...

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