BBC Micro and Acorn Electron demo effects

[0xC0DE]

EDIT: Currently converting all demo effects to work on the BBC Micro and on the Electron. Post renamed to reflect this.

Trying to push my 6502 coding skills and the humble Acorn Electron to the limit

https://www.youtube.com/watch?v=lT0qxnIz3JU

[oss003]

Nice job, looks great ....

Greetings
Kees

[Elk2019]

Simply mesmerising! A cool demo of your 6502 skills. Who knows, this may kickstart a demo scene on the Electron. Despite its limitations, the Elk is still an amazing computer and I commend all fellow users who continue to push the boundary and the Elk to its limits!

[0xC0DE]

Thanks guys
This is MODE 5. Double chunky spaced pixels. Real time calculation. No colour palette tricks or pre rendered animation.
The raster can be varied in size to alter the frame rate.
Looking for different effects that are still fast enough.

[tom_seddon]

Who'd ever have thought the Electron had it in it!

Would the screen address granularity be good enough to create something like one of the effects here? - http://norecess.cpcscene.net/the-elders-scrollers.html

--Tom

[davidb]

Would the screen address granularity be good enough to create something like one of the effects here? - http://norecess.cpcscene.net/the-elders-scrollers.html

Yes. I found that technique quite inspirational and I've been thinking about doing something like that for a while. Possibly also throwing in some palette changes as well.

One of the things that stalled my efforts was making music. I spent some time trying to write music players and compose tunes, and those things took a lot of effort.

[0xC0DE]

I remember seeing that demo technique for the first time and being blown away, thinking "this is impossible!"
And just like DavidB I have been toying with the idea of trying this on the Electron ever since. I like the challenge of squeezing every last drop out of my standard (!) Electron. Would be cool to see what others can do. Especially when it is work in progress. No music required DavidB

[0xC0DE]

OK, I just had to see if I could make this work on an Electron...

viewtopic.php?f=53&t=16971

Enjoy

[davidb]

I remember seeing that demo technique for the first time and being blown away, thinking "this is impossible!"
And just like DavidB I have been toying with the idea of trying this on the Electron ever since. I like the challenge of squeezing every last drop out of my standard (!) Electron. Would be cool to see what others can do. Especially when it is work in progress. No music required DavidB

We can build on some of the tricks developed in the 1980s in games like Firetrack, Impact! and Sphere of Destiny to do things like vertical scrolling and palette switching. There were also some interesting articles in Electron User that showed how to do horizontal and vertical mode splits.

I combined scrolling and palette switching for a title screen: MODE 1 Scrolling and Palette Effects. I'd like to revisit that to do something like Sphere of Destiny's road, but with a sun/moon/city rising from the horizon.

[0xC0DE]

Your title screen is very impressive. That is exactly what I'm talking about! It's giving me an idea or two.
I've seen plenty vertical mode splits but never horizontal I think. Do you have an example?

I really like seeing active Electron coders
There are not many left I guess.

[davidb]

Your title screen is very impressive. That is exactly what I'm talking about! It's giving me an idea or two.

Thanks! That's the idea.

I've seen plenty vertical mode splits but never horizontal I think. Do you have an example?

See pages 28 and 29 of Electron User #7.07 April 1990.

[simonm]

Very cool!

[0xC0DE]

Proof of concept on Acorn Electron.
MODE 1, 25 fps (also works @50fps), smoothly moving background (320x256), static masked sprite (32x32) in the foreground, colour cycling.

This is the NON-epileptic version (but can still cause motion sickness ):

plasma-no-color-cycling.ssd

(24.5 KiB) Downloaded 107 times

This is the version with eye-watering colour cycling. Do NOT watch if you have epileptic tendencies!

plasma.ssd

(24.5 KiB) Downloaded 101 times

You can also watch it right here: https://www.youtube.com/watch?v=E7CGErkhqho

[0xC0DE]

The classic colour cycling demo effect on an Acorn Electron. Screen MODE 1 again. Usually max 4 colors. Now very colourful because of rapid palette switching and dithering.

Watch the video: https://www.youtube.com/watch?v=J4LJaTtDYPM

Edit: it also works on a real Electron but it is a bit fiddly to get it just right. I will share the version that works on my standard Electron and hope to find out if it works on others as well.

[0xC0DE]

Edit: it also works on a real Electron but it is a bit fiddly to get it just right. I will share the version that works on my standard Electron and hope to find out if it works on others as well.

Here is the tape image of the version that works "out of the box" on my standard Electron (no expansions). It shows smooth colour cycling at medium speed, appearing to move towards the bottom of the screen.

colors.uef

(24.18 KiB) Downloaded 104 times

And this is the disk image:

colors.ssd

(21.5 KiB) Downloaded 108 times

Every Electron emulator I've tested yields a slightly different result and requires some tweaking.
To tweak the timing press CURSOR UP or CURSOR DOWN. Watch the topleft of the screen where a number appears according to the current setting. Press ESCAPE to hide this number again.

On my Electron I get good results at values 01, 0E, 0F, 36, 37, 38, 39, ...
I would really like to know which values work on your Electron

[oss003]

Your Youtube links aren't working ......
Video not found

Greetings
Kees

[0xC0DE]

Hi Kees, that's really strange. I have just tested every single YouTube link on this page and they seem to work fine; for me at least.
What happens if you go to my videos through my YouTube channel page?
https://www.youtube.com/channel/UCWZ3gg ... 1ZMdN9-Cow

[oss003]

Hi Kees, that's really strange. I have just tested every single YouTube link on this page and they seem to work fine; for me at least.
What happens if you go to my videos through my YouTube channel page?
https://www.youtube.com/channel/UCWZ3gg ... 1ZMdN9-Cow

All the same result ... are the video's public?

Greetings
Kees

[Pernod]

All the same result ... are the video's public?

They're all good in UK.

[0xC0DE]

are the video's public?

Yes they definitely are. Are you currently in China, Kees?

[kieranhj]

These are all great BTW, fantastic work! Now if you can just get the Electron ULA to play a decent tune then you’ll have all the ingredients for a demo production.

[0xC0DE]

Thank you!

if you can just get the Electron ULA to play a decent tune

Now there's a challenge!

Has anybody ever gotten a decent tune out of the Electron's speaker?
(any particular game with an outstanding tune I should check out for example?)

[tricky]

Nice work, would have replied earlier, but got sidetracked looking at old threads about changing the whole palette per scan line on the Electron.

[0xC0DE]

Thank you tricky. And be careful, that's how I got sucked into coding all these effects. CAN... NOT... STOP!

[Pernod]

Lots of lovely test cases for MAME

[0xC0DE]

Lots of lovely test cases for MAME

Can you confirm they are working on MAME? I haven't tested yet.

[Pernod]

Can you confirm they are working on MAME? I haven't tested yet.

I wasn't expecting them to look great in MAME but they're not far off. The worst is the plasma with the static acorn, it jumps around a little.

[jms2]

Every Electron emulator I've tested yields a slightly different result and requires some tweaking.
To tweak the timing press CURSOR UP or CURSOR DOWN. Watch the topleft of the screen where a number appears according to the current setting. Press ESCAPE to hide this number again.

On my Electron I get good results at values 01, 0E, 0F, 36, 37, 38, 39, ...
I would really like to know which values work on your Electron

The colors demo works perfectly on my Electron without needing to change anything from the default settings. It is VERY impressive!
The plasma demo suffers from the acorn having ghosting effects which move around the screen periodically. To be honest this is impressive too, even though not intentional!

[0xC0DE]

Real time ZX Spectrum-like loading (and saving) screen for the Acorn Electron anyone?

Watch my Speccy loader while loading and saving a program on my actual Electron: https://www.youtube.com/watch?v=MhnN_tYFbBQ
(you may want to turn down the volume a little bit for this)

8-bit inception!!

[0xC0DE]

The colors demo works perfectly on my Electron without needing to change anything from the default settings. It is VERY impressive!
The plasma demo suffers from the acorn having ghosting effects which move around the screen periodically. To be honest this is impressive too, even though not intentional!

Thank you very much! I will look into the ghosting effect. Can't remember if I've tested that particular one on all available Electron emulators AND on a real Electron. Probably not!

@Pernod: I will be testing all of them in MAME as well. Thanks for reporting back to me.