Hello eveyone,

I have spent quite a few years wondering why there wasn't a site for old BBC programmers.

I have been programming since before the Beeb, but the BBC B has always been my favourite.

I have put up some videos of a game that Gil Jaysmith (Specky Repton 1 & 2) and I wrote in the early eighties for the BBC.

http://www.youtube.com/watch?v=bxUousTHFeU
http://www.youtube.com/watch?v=2kkz_y07kNM
http://www.youtube.com/watch?v=52eOSfXzUzo
http://www.youtube.com/watch?v=jlmhSMYxJOs
http://www.youtube.com/watch?v=IkhbK1UjDEo
http://www.youtube.com/watch?v=381WtEoHqnY
http://www.youtube.com/watch?v=ZNFMTVwQBvQ
http://www.youtube.com/watch?v=2-aCeUV_82M

I will add a disc image of a newer version of the demo as soon as I can get it of my 5.25s and the source code, just in case anyone fancies a bit of open source dev - thanks to the reminders from the site organisers

Richard Broadhurst

Jeltron by Richard Broadhurst and Gil Jaysmith .
The graphics were by one of Gil's friends - I will try to get his name.

If shift-break doesn't work, type *EXEC!BOOT [RETURN] to run

The kayboard layout is a bit tricky as we had to avoid key clashes, your best bet is to use a couple of joysticks.


I would advise a couple of fire power-ups then a couple of turbo speed-ups.

We never ballanced the waves as this was just the version that we sent to the publisher to see if they would considder it - they offered us a contract, but personal circumstances meant that we never finished it.

There are several waves of aliens, then a mother-ship, then the whole things repeats with parallax landscape or star-fields and or firing aliens.

I have a newer version of the game somewhere with bullets that spread out and an orbiting mini-ship.

All feedback welcome, but I don't really have time to do any coding work, but will support the opensource version if i can find it.

richard

I guess this thread is a little back to front and maybe a little off topic.

I have quite a bit of BBC 6502 experience and would be happy to contribute to projects (even my own if I get enough spare time).

Richard Broadhurst

Off topic? No way! That's brill!! Glad you finally stumbled upon us!

Really super-smooth without any flicker - I'm impressed. Nice little mode split as well, which I didn't even notice until a little way in.

So do you have source code to this? It'd be nice to see how it all worked, and maybe someone could pick it up where you left off...

Incidentally, was it you two who once experimented with a super-smooth horizontal scrolling routine, using R3 of the CRTC to move by one Mode 2 pixel at a time (but it apparently didn't work on all monitors)? Tom Walker (another regular here) and I were talking about it a while ago, and he was sure he'd read that it was Gil Jaysmith who'd tried it.

Anyway, good to see you here, and thanks for posting the disc image

We tried vertically, but I don't remember ever trying horizontal.

Gil was Gil Johnson-Smith back then.

Here is the newest source I can find that works until I can get my drive 0 working and check the other 50+ discs.

richard

To build:

CH."source1"
copy last line to save exe

To Run:

*l. r.data
*rtype

good luck - DGen builds R.Data - I will have to lookup my old notes for what the different data files are for or work it out from the source.

What about the star-field

richard

The starfield is nice, but what stands out more for me are the flicker-free sprites which also move pixel-by-pixel horizontally. How were you doing that? Did you have 4 copies of each one (for each pixel position in a byte in Mode 5), or were you actually shifting the data and plotting it on the fly? Also, really nice to see such a large end-of-level boss

Incidentally it's bloody difficult! I can't get so much as a power-up, though I guess it's a game that has to be played 2 player, otherwise the odds are against you! Unfortunately the emulators don't cope with so many simultaneous keypresses (but that's a shortfall of the keyboard under Windows rather than anything else...).

Flicker free was one of the main aims, there is flicker between the landscape (not the parallax of course) and pretty much anything else - I think it was fixed for the players in a later build. The aliens were never meant to get close enough to share a char block.

The main things that the game needs to be playable is to have all of the alien waves and landscape re-designed.

I have a later source with the orbiting shield blob and spreading shots power-ups, but there is a bug after the first EoLvl boss.

We had four copies of each sprite, although some were to have been used for animation for aliens that always move horizontally by the same amount per frame. I did bit shift in other games that I wrote where there were less sprites, but there just aren't enough cycles for the number of sprites we wanted.

The best bet is to get two shot power-ups and then two or three speed power-ups, you can then kill the EoLvl boss by flying backwards nose to nose, going up or down at the last moment ready to swoop in again - You did notice that the laser if "fully-automatic"!.

The landscape bits are impossible with the aliens - I designed them without aliens, but for the demo we tried to show what would be available to a decent level designer.

The renderer chases the scan-line and only ORs where it has to, SToring where there is no overlap.

richard

Here are the data files and the BeebAsm 1.4 source code for the Jeltron demo - I have included a disk image and .bat that will require your BeebAsm and BeebEm (any decent emulator should be OK) paths adding.

The original demo loads the data and then splats over the middle with code, so if you have a slow connection to your beeb, you could re-arrange it that way.

When I get a little more time, I will try to document the source and maybe even the data file formats - Unless Gil wants to chip in - sorry, I still don't have the source for the newer versions with orbiting blob and spreading bullets etc.

I would love someone to take up the gauntlet and add more game play or levels.

Richard

PS I would like to than RichTW for BeebAsm, it only took three hours to port from original BBC basic/asm to BeebAsm.

Sorry, here is the .zip attachment

Replying to myself again

here is the same code, but with most of the stars code variables and some of the movement ones named.

No offers to take over this code yet, so I will keep tidying when I get a chance.

Richard, the asm source looks like the same one as in the previous zip. Is it supposed to be different?

Sorry, yes, I must have posted from the backup directory!
I will post the first pass at fixing all those too small variable names later.
Are you interested in doing any work on the game or levels etc - if so, what would help most?

I'm afraid I'll have to leave that task to a more capable individual . I haven't done any serious coding in 20+ years and I'm still trying to dust the cobwebs off the few cells that had any bit of beeb info imbedded in 'em

What am I doing pouring over your code then, I hear you ask? Well, apart from perhaps picking-up on a few techniques or tricks others may use, I find it a great way to try to trigger those old cells...(or kill them off altogether ).

There are some very knowledgeable and talented folks here (& stardot) and I'd be surprised if someone doesn't take up the gauntlet

But please do keep documenting your code - I'm sure someone will pick it up sooner or later and, it probably goes without saying but, the more documentation/notes you have on it, the better!

-Martin.

Here is the correct .zip from above.