what should i write next?

suggest games that you’ve always wanted to see on acorn platforms
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richardtoohey
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Re: what should i write next?

Post by richardtoohey » Tue Jul 14, 2020 10:21 pm

There's Peter Johnson's Airlift ... but don't think there's any sea in that, so not the right game ...

Michael Brown
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Re: what should i write next?

Post by Michael Brown » Wed Jul 15, 2020 8:16 am

Hi Adam,
I believe the game you refer to is Copter Caper from A&F.

regards,
Mick.

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Re: what should i write next?

Post by Adam James » Wed Jul 15, 2020 7:10 pm

Michael Brown wrote:
Wed Jul 15, 2020 8:16 am
I believe the game you refer to is Copter Caper from A&F.
That's the one! Thank you:)

I've just played it again now, making a serious attempt to get somewhere, and got past the first bonus stage. It's a pretty good game I think.

At first it seemed a bit down to random luck as to whether a submarine will kill you as you don't get time to move out of the way if it's just below the surface. Then I realised you really need to abort any rescue as soon as you see a sub that high up if you want to stand a chance; perhaps that's the idea.

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tricky
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Re: what should i write next?

Post by tricky » Sun Aug 23, 2020 1:27 pm

I was just sidetracking myself again, anything rather than get on with Moon Patrol!
Here is a Pacman mock-up I mad a while ago.
Mockup.png
Mockup.png (7.34 KiB) Viewed 720 times
The original colour ghosts are left, with their MODE 1 replacements next to them.
I hadn't decided whether to stack the collected "fruit" on the right, or just show the last few.
I also wasn't sure about sticking the scores out the side, or just to drop the 0 and fit it more neatly.
The beeb can do the full 288 pixels high, but you wouldn't see them on nearly any displays, hence shuffling things around a bit.

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Re: what should i write next?

Post by AJW » Sun Aug 23, 2020 1:52 pm

Colourful as snapper.

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pixelblip
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Re: what should i write next?

Post by pixelblip » Sun Aug 23, 2020 2:53 pm

I like Gorf....that is an exciting game

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kieranhj
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Re: what should i write next?

Post by kieranhj » Sun Aug 23, 2020 2:54 pm

Love the MODE 1 ‘hires’ look - I think dithered ghosts would work well too.

EDIT: I see what you mean about the challenge of having a 288 pixel high screen. I think having lives and fruit on the side looks fine but the scores feel a bit cramped. Any chance you could leave them at the top? What height would that end up as?
Bitshifters Collective | Retro Code & Demos for BBC Micro & Acorn computers | https://bitshifters.github.io/

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tricky
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Re: what should i write next?

Post by tricky » Sun Aug 23, 2020 5:00 pm

The maze is actually 248 high, so there is room, but that means the ghosts span 3 char rows - not the end of the world.
With it all shifted by 4 pixels, everything moves in two char high rows and there probably wouldn't be any *TV requests.
Since things have to move vertically, it probably wouldn't matter if they did H and V as the code would have to cope for when they were.
mockup.png
mockup.png (5.87 KiB) Viewed 666 times
I'm not sure if Donkey Kong would be worth the effort as it moves horizontally 2 pixels every 3 frames - plus Nintendo!

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Re: what should i write next?

Post by marcusjambler » Sun Aug 23, 2020 5:41 pm

Hi Tricky

Have you considered doing a hi-res ( mode 0 or 3 ) port of Atari's 'Lunar Lander' ?

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tricky
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Re: what should i write next?

Post by tricky » Sun Aug 23, 2020 11:01 pm

I was planning on doing the arcade game in mode 1 or 4 but got sidetracked with line sewing routines. I can't remember if it used math box, but probably only the scaling built into the vector unit. Mode 0 would be a bit of a pain with it's half width pixels making lines appear different widths depending on their angle. Mode 1 would be for different intensities.

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Re: what should i write next?

Post by fwibbler » Tue Aug 25, 2020 7:55 am

Don't know if it would be of interest to you, but have you read Bob Papes book about how he programmed R-type for the ZX Spectrum 48k?
I find it a great read and it shows just how hard he had to work to fit it all into the machine even as a multiload game.
It's a free download in PDF format (although I enjoyed reading it so much I had it printed in paperback and then hardback.)
http://www.bizzley.com

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Re: what should i write next?

Post by tricky » Tue Aug 25, 2020 12:15 pm

I have, and I enjoyed it too.
I am a bit of a snob when it comes to arcade ports - I want them at full frame rate and wit the correct movement (usually MODE 1 pixel resolution).
On the 8bit systems, the aliens often move in character squares, and sometimes the landscape too!
I think it was the right compromise on the speccy, but I still don't like it (having to compromise, not the game).
I guess with most games after about 82 and some before, it was the only way to get the game onto the platform at all.

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Re: what should i write next?

Post by fwibbler » Tue Aug 25, 2020 2:21 pm

Reading his book it seems he had about 42k to fit everything into (which means the spectrum screen takes 6ķ???).
Now to get that amount of free ram on a Beeb you'd need at least 32k of sideways ram, maybe more.
It might even have to be Master only and even thouh Beebs have more powerful CPUs, I'd guess that 50fps will be impossible with 20-30 sprites on screen!

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Re: what should i write next?

Post by AJW » Tue Aug 25, 2020 4:16 pm

yet Graham Richardson wrote Nevyron.

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fwibbler
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Re: what should i write next?

Post by fwibbler » Tue Aug 25, 2020 8:41 pm

Which doesn't compare with R-type on just about any other system, except possibly the original Amstrad version and even that feels faster, more responsive and less clunky than Nevryon (imho)
Maybe it just lacks playability but Nevryon, like Commando, was a massive disappointment to me years ago and if used as a BBC version of R-type, is at the bottom of the ports list (again, like commando).

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Re: what should i write next?

Post by tricky » Thu Sep 03, 2020 1:15 pm

fwibbler wrote:
Tue Aug 25, 2020 2:21 pm
...Reading his book it seems he had about 42k to fit everything into (which means the spectrum screen takes 6ķ???)...
256x192 MODE 4 (6K) + 3/4K for the per character colour (attribute) data.
fwibbler wrote:
Tue Aug 25, 2020 2:21 pm
...I'd guess that 50fps will be impossible with 20-30 sprites on screen!
Frogger is about the optimal arrangement for maximum sprites, that move independent of the background and most of each other.
Astroblaster draws its 16 x 16x16 sprites in less than a 1/4 of a screen, but they move in formation and don't have a background.

The R-Type like proof of concept that I posted uses a smaller screen, so the sprites can be smaller and quicker to draw and still look in scale.
My plan was to have different types of waves that exploit different optimisations to have large waves move in formation, with smaller waves for individual behaviour. There would also be waves that only move horizontally in character rows to make address calculations cheaper.
All of these could be non-overlapping to allow write only plotting or some individuals could be allowed to overlap others or the scenery.
There would also be sprites that moved as part of the background, so a gun emplacement would only actually be the barrel until the whole things was replaced with a burnt-out turret.
I was/am hoping that this could make for a game that felt like it had lots going on and still hit 50fps.

In an unrelated not, I've been looking at another port, but as usual got stuck with sound.
I found these samples that sound good, but am having trouble converting them to the beeb. The simple beeps are fine and I can probably do the explosions, but things like thrust and heartbeat are tricky (but not my kind of tricky).

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Re: what should i write next?

Post by fwibbler » Fri Sep 04, 2020 10:43 am

Yes, the BBC doesn't really do low frequency sounds does it.
I'm trying to think of a game that does it and I can't so far.
I think Meteors just uses the 2 lowest suitable notes that it can and makes do with them.
Annoyingly, the ZX Spectrum has no trouble making that kind of sound :oops:

For the thrust sound wouldn't something like...
SOUND 1,0,60,10
SOUND 0,-7,7,10
... do the trick?

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tricky
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Re: what should i write next?

Post by tricky » Fri Sep 04, 2020 1:51 pm

Thanks, I'll try it later.
I was thinking white or periodic noise at the frequency of channel 2, or which ever it is in basic. That may be what you have suggested. Another option is too generate a ~100Hz wave with interrupts turning a highest frequency channel on and off.
Because it is all analogue, really it needs samples, but the 6502 is already maxed out. They would be half price if the IRQ had been handled like the NMI.
Even the firing has such a distinctive sound that it probably isn't going to sound anywhere near, especially with my audio skills.

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Re: what should i write next?

Post by AJW » Fri Sep 04, 2020 6:12 pm

fwibbler wrote:
Fri Sep 04, 2020 10:43 am

SOUND 1,0,60,10
What does that do?

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Re: what should i write next?

Post by fwibbler » Fri Sep 04, 2020 6:41 pm

It sets the pitch of the variable white noise on channel 0

I should add that those two sound statements only work together when run in the form of a program..
Ie:
10 SOUND 1,0,60,10
20 SOUND 0,-7,7,10

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Re: what should i write next?

Post by fwibbler » Fri Sep 04, 2020 11:04 pm

I don't think it will be possible to have the same sounds as the arcade version.
Best to just play to the Beebs strengths and choose sound effects that sound good on it.
Meteors gets this pretty much right I think.

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Re: what should i write next?

Post by tricky » Wed Sep 16, 2020 8:31 pm

Yesterday, or was it Monday now, I thought I would have a go at the track for a Pole Position like game.
The maths turned out to be very easy and the track, although fiddly wasn't too bad.
The problem is that it takes 3/4 99% of a frame to draw the track, which I don't think leaves enough time for cars and scenery.
This demo has a couple of pixels left lying around occasionally, this is an easy fix, I just haven't bothered.
You can "turn" with Z,X and move left and right with Q,W but doing this will show up some more corruption that would get fixed with stopping the track from wrapping around the screen and cost some more CPU cycles.
I don't think that I will be going any further with this project.
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Only a tech demo: Q,W,Z,X
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