New Super Mario Bros (demo)

[PeteProdge]

MrTom has put the demo on a real Spectrum +2 and has captured the results...

https://www.youtube.com/watch?v=-bW6mo81voI

[Ast A. Moore]

This is not what exactly what it looks like on real hardware. I mean, I don’t know how he captures his Speccy’s video output, but on my Spectrum and CRT TV the flicker is not that apparent (when synced up properly).

[PeteProdge]

This is not what exactly what it looks like on real hardware. I mean, I don’t know how he captures his Speccy’s video output, but on my Spectrum and CRT TV the flicker is not that apparent (when synced up properly).

I'm chatting with Mr Tom in a Discord window.

His explanation, which he's asked me to post here: "it's cos I zoomed the image in to get rid of the massive borders. That and the YT compression did a number on it."

I would also do a capture, as a massive video nerd who likes to capture things at the right framerate, but my only ZX Spectrum blew up years ago. I only play Spectrum games through emulation.

Thus, I've only played the Super Mario Bros demo on Fuse, and it looks very much like Mr Tom's video.

Of course, I'd like to see differing views on this.

[Ast A. Moore]

Thus, I've only played the Super Mario Bros demo on Fuse, and it looks very much like Mr Tom's video.

I know. Hence my comment above.

Fix up your Speccy!

[4thRock]

That YT video should be at 50fps, not at 60fps ! Capturing at 60fps creates duplicate frames and also breaks the smooth scroll (on all games, not only this). Switching your PC's refresh to 50hz solves this problem on most emulators.

I'm no expert (so correct me if I'm wrong) but the closest digital equivalent of the Spectrum's output, with no scaling, is 384*288@50p.
That's the full borde, with a 256x192 active area in the middle.

Scaling 2x (pixel doubling) gives you 768x576@50p, which is a valid modern SD resolution.
So I'd say this is the ideal resolution for captures. Many emulators allow you to selected this mode for full screen.

You can then upscale the capture to 720p or 1080p for YouTube upload with minimal artifacts.

[5MinuteRetro]

In ZXDS either set the input to Kempston, then choose that in the games menu (Left/Right moves, Up = Jump and Fire = Run) or choose QAOPS and set the controls manually (O/P moves, Q = Jump, Space = Run).

Ah... I think that's where I've been going wrong! I assume fire was purely for jump, so I'd been configuring accordingly. I didn't realise that there's a separate run control. I'll try it next week -- I left my DS at the office.

Just to close this out for me... this worked. I didn't realise that 'fire' was 'run', so I'd been mapping 'jump' to the 'fire' button, so I couldn't run. I can now clear those pipes, no bother. And this really is a staggeringly-good demo!

[5MinuteRetro]

This is not what exactly what it looks like on real hardware. I mean, I don’t know how he captures his Speccy’s video output, but on my Spectrum and CRT TV the flicker is not that apparent (when synced up properly).

On ZXDS on my DS the effect is absolutely superb. Not quite 'static' but virtually no flicker, so the distinctly-un-Spectrum grey of Mario (for example) looks as-near-as-dammit solid when he's standing still. The trickery becomes more apparently when he (and other stuff) is moving, but I'm still agog about this effect. In fact, I'm about to start a new thread just to ask about it... (assuming there are no other gigascreen threads already -- I'll check before I post!).

[Ast A. Moore]

Many emulators allow you to select this mode for full screen.

Not all computers let you choose arbitrary refresh rates, though. My laptop, for instance, is locked at 60 Hz. Ain’t nothing I can do about it.

[Ast A. Moore]

I'm still agog about this effect.

Back in the day, some games used this effect for creating extra colors. Nether Earth comes to mind. It’s used (sparingly) in the radar.

[5MinuteRetro]

I'm still agog about this effect.

Back in the day, some games used this effect for creating extra colors. Nether Earth comes to mind. It’s used (sparingly) in the radar.

Can confirm... just this second tried it. Superb! I never played that game but I'm sure I would've noticed it as a kid, so I'm still surprised I didn't see this effect more commonly. Still, a whole new ZX thing to explore. I've created a new thread...

[Ersh]

On ZXDS on my DS the effect is absolutely superb. Not quite 'static' but virtually no flicker, so the distinctly-un-Spectrum grey of Mario (for example) looks as-near-as-dammit solid when he's standing still. The trickery becomes more apparently when he (and other stuff) is moving, but I'm still agog about this effect. In fact, I'm about to start a new thread just to ask about it... (assuming there are no other gigascreen threads already -- I'll check before I post!).

ZXDS is awesome. The screen refreshes at solid 50hz which gives you silky smooth scrolling and colour blending effects without hiccups. As I mentioned the DS' LCD is also slow and prone to blur, which actually reduce flicker in gigascreen graphics.

I use the emulator extensively and it's worked perfectly with almost everything I've thrown at it. Though there are a few instances where the DS' LCD blur gets in the way. In Paranoia Complex; the scrolling messages are impossible to read. In Death Star Interceptor; the turret lasers during the trench-run are difficult to see due to their speed combined with the LCD blur. Not the emulator's fault though.

[4thRock]

Many emulators allow you to select this mode for full screen.

Not all computers let you choose arbitrary refresh rates, though. My laptop, for instance, is locked at 60 Hz. Ain’t nothing I can do about it.

In that case you can try to speed up emulation a few % so that the screen refresh matches 60hz...

[4thRock]

I'm still agog about this effect.

Back in the day, some games used this effect for creating extra colors. Nether Earth comes to mind. It’s used (sparingly) in the radar.

Or Chuckie Egg to prevent attribute clash with the main character (but it's only attribute change, pixel data remains the same). On a CRT you can't see any flicker (I guess colors mix better than pixel patterns).

[5MinuteRetro]

Or Chuckie Egg to prevent attribute clash with the main character (but it's only attribute change, pixel data remains the same). On a CRT you can't see any flicker (I guess colors mix better than pixel patterns).

Oh man -- so it does! Thing is, that's quite flickery too, and it's a flicker that I remember from playing as a child. It's not very effective, to be honest, and seems only for 'Man', not the birds. Now I'm wondering what Super Mario Brothers' use of gigascreen gets right where others get wrong? Actually, I think I kinda know the answer: I think SMB's implementation is really more about pixel-blending than the creation of 'new' colours. By blending two offset pixel forms of Mario, the author has managed to create parts of his body that look like a near-solid grey. Ditto the reds on the bottom platform, and bits of green on the pipes.

[djnzx48]

I never considered the attribute flickering in Chuckie Egg to be an intentional use of the effect. I always thought that was an artifact of the way attributes were updated - you'd see flickering if the attributes of the player were drawn and then quickly reverted to the old value (to 'undraw' them).

[djnzx48]

At the end of level 5-2 it takes me back to 1-3. Is this right??

I replayed this and found there is an actual ending, after World 5-4.

Spoiler

[4thRock]

it's a flicker that I remember from playing as a child

I noticed it two years back on a retro gaming exhibition. They had a Spectrum connected to an old CRT TV and I noticed right away that attributes were mixing.
It's possible that on CRT TVs color data really gets averaged between successive frames, but since the Spectrum's output is non standard it's hard to know. PAL does require two lines to extract colour information...

[djnzx48]

The author posted some more comments here. I attempted to translate:

For anyone who's interested:

1. About gigascreen and attributes:
- Initially I planned to flicker with attributes using gigascreen to get intermediate colours. And that is exactly how it worked. There are videos of this working from 2016-2018.
Then, after a couple of weeks of testing on various [real hardware], I decided not to flicker with attributes, because it is impossible to tolerate it for a long time. People in chat rooms supported this.
All the same, this is a game, not a demo with effects, where one effect lasts no more than 30 seconds.
And God forbid, someone will play at 60Hz - and in general there will be a complete trash with flowers.

For those who pick at this: flickering with attributes is absolutely worthless.
Look at the memory cells #ff00-#ff1f on pages 5 and 7 - these are the attributes of blocks, two bytes per block.

2. About the black background:
With a black background, you can use up to 14 different INK variants, including two BRIGHT variants.
Having a colour background, you need to consider how much of the background colour is combined with the INK colour, and not use BRIGHT.
For example, with a blue background, only black and blue INK can be combined. Well, with a little tension, red. And colours green and yellow simply cannot be used.
The engine, which collects the game into a disk/tape image, is able to collect levels both with a dark background, and with a light background. This is set through the palette configuration.
And for some time level 4-1, with the desert, had a light background.
It is important that for a light background different sprites are used, than for dark...
But this is no longer important, because the whole set of sprites is automatically compressed during the assembly process of the game - you can use whatever you want.

3. About speeding up the output on the black background:
There is no profit - neither from using a black background, nor from any cleaning on a black background. Because regardless of the colour of the attributes, every frame needs to be cleaned and painted.

The engine always works the same, regardless of the colour of INK and PAPER. What attribute to paint, we do not care at all.
The only exception to the rule: if the character's INK colour matches the background's INK colour, then we save about 1000 cycles, because such a character does not need to be painted in a different colour.

[+3code]

Hey, it's wonderful. I've too developed my own "Mario" for zx

It's a small simple demo (with Charade Engine):

https://sites.google.com/site/plus3code ... pancho.rar

(Keyboard: OPQA )