Mmm....
https://www.indieretronews.com/2022/10/quake-engine-running-on-zx-spectrum.html
That's mighty impressive! Great that the spectrum scene keeps raising the bar.
It never was good to have a spectrum port on the CPC but maybe this time it would be cool :)
Quote from: Prodatron on 18:56, 07 November 22It never was good to have a spectrum port on the CPC but maybe this time it would be cool :)
You wouldn't want a port of that. That CPU is getting CRUUUUNCHED!!! It would end up running super slow on the CPC, so you would need it done from scratch to get good speeds.
We already had driller in 1987, with colorz ;D
https://www.cpc-power.com/index.php?page=detail&num=772
Quote from: sigh on 19:21, 22 November 22Quote from: Prodatron on 18:56, 07 November 22It never was good to have a spectrum port on the CPC but maybe this time it would be cool :)
You wouldn't want a port of that. That CPU is getting CRUUUUNCHED!!! It would end up running super slow on the CPC, so you would need it done from scratch to get good speeds.
Why do you say that? The CPC wasn't 'automatically' half the speed of the spectrum when running spectrum code. It depends on what is being done, and how.
With an arcade game from the commercial era, particularly one with software scrolling, the vast majority of the cpu time would usually be spent simply writing video memory with a minority on game logic. In cases like that, yes, the CPC having twice as much video memory to write using the same code was often very much slower.
Without knowing any detail it's only possible to speculate, but in something where the bulk of the cpu time is perhaps spent on calculations or other logic, these are not the sort of things the CPC would have to do twice as much of compared to the spectrum, so any speed difference is unlikely to be nearly so pronounced. It just depends on how it goes about it.
No, you're right, Axelay. It won't be "super slow", nor would it run at half the speed, but still noticeably slower than the Spectrum version. Unless there's some Spectrum specific code (which I highly doubt), the 3D engine can be used as is on the CPC, and only the rendering part (drawing lines and deleting the 3D window) and the keyboard routines would need a redo.
The one thing that might make up for a loss of speed would be the four possible MODE 1 colours plus added shading of these colours. You can imagine the black/white patterns in the Speccy Quake demo having more varied surfaces.
Basically, what Driller, Darkside, etc. did on the CPC vis a vis the Spectrum monochrome versions, only a tad faster even than the Freescape engine, from what the Speccy demo shows.
Quote from: Axelay on 13:39, 23 November 22Quote from: sigh on 19:21, 22 November 22Quote from: Prodatron on 18:56, 07 November 22It never was good to have a spectrum port on the CPC but maybe this time it would be cool :)
You wouldn't want a port of that. That CPU is getting CRUUUUNCHED!!! It would end up running super slow on the CPC, so you would need it done from scratch to get good speeds.
Why do you say that? The CPC wasn't 'automatically' half the speed of the spectrum when running spectrum code. It depends on what is being done, and how.
With an arcade game from the commercial era, particularly one with software scrolling, the vast majority of the cpu time would usually be spent simply writing video memory with a minority on game logic. In cases like that, yes, the CPC having twice as much video memory to write using the same code was often very much slower.
Without knowing any detail it's only possible to speculate, but in something where the bulk of the cpu time is perhaps spent on calculations or other logic, these are not the sort of things the CPC would have to do twice as much of compared to the spectrum, so any speed difference is unlikely to be nearly so pronounced. It just depends on how it goes about it.
Ahh okay.
Quote from: MaV on 21:02, 23 November 22No, you're right, Axelay. It won't be "super slow", nor would it run at half the speed, but still noticeably slower than the Spectrum version. Unless there's some Spectrum specific code (which I highly doubt), the 3D engine can be used as is on the CPC, and only the rendering part (drawing lines and deleting the 3D window) and the keyboard routines would need a redo.
The one thing that might make up for a loss of speed would be the four possible MODE 1 colours plus added shading of these colours. You can imagine the black/white patterns in the Speccy Quake demo having more varied surfaces.
Basically, what Driller, Darkside, etc. did on the CPC vis a vis the Spectrum monochrome versions, only a tad faster even than the Freescape engine, from what the Speccy demo shows.
What about mode 2? Would that also help with the speed?
That might work, if you'd use the same pixel count in X and Y as the Spectrum demo. From what I can discern it does not seem to use the standard 256x192 resolution but a smaller arbitrary one (I may be mistaken). You'd be close or equal to the speed of the quake demo.
But then you have a squashed picture since a MODE 2 pixel is half the size in X of a (nearly) square MODE 1 pixel. If you want to retain the proper screen ratio you are back to the same screen size as the MODE 1 screen which means the same number of bytes but double the resolution in X. Nothing gained.
If the CPC used bitplanes for colours (so two bit planes for four colours, similar to the EGA card, the Amiga and the Atari ST), using only one plane might have given us the same properties of a Spectrum monochrome screen. We would have had the speed of the Spectrum screen while also having the flexibility of additional two colours by plotting on the second bit plane, trading speed for colours on occasion.
Quote from: MaV on 00:34, 24 November 22If the CPC used bitplanes for colours (so two bit planes for four colours, similar to the EGA card, the Amiga and the Atari ST), using only one plane might have given us the same properties of a Spectrum monochrome screen. We would have had the speed of the Spectrum screen while also having the flexibility of additional two colours by plotting on the second bit plane, trading speed for colours on occasion.
I can't but help but think had that been the case, there'd have been a lot more monochrome spectrum ports in the commercial era! It sounds like something that would have reduced the effort to make a monochrome mode 1 game, but increased the effort (with more code changes required) in making something with more colour.
Quote from: Axelay on 11:01, 24 November 22I can't but help but think had that been the case, there'd have been a lot more monochrome spectrum ports in the commercial era!
:D Yes, that's exactly what I thought while writing my post. It would have been too easy to just omit colour altogether, and we'd have even less original CPC games.
(But a bit plane mode has its advantages).
This is a very impressive 3d engine for the Speccy but I can't help but feel that it's a bit misleading calling it a "Quake engine" if it can't run Quake wads. Which would be ridiculous...
I was thinking, you could make it 10x faster than the spectrum by making it 20x jerkier