MiSTer FPGA Forum

Just based on some brief research (I'm not skilled), it looks like the composite blend on the Genesis core is a bit more complicated than a filter. That being said, is it translatable to other cores? I'd love to see it on all the consoles (outside of the Gameboys, which already look fantastic with the LCD filters)!

Is it possible to develop a 'standard' for composite blend across all cores? (much like how with every core, MiSTer has 'defaults' for enabling HDMI output, scaling, etc.)

It was really needed on Megadrive since some games rely heavily on composite artifacts... but other cores? Which ones do you think would benefit from that?

Newsdee wrote: ↑Fri Dec 04, 2020 7:55 am It was really needed on Megadrive since some games rely heavily on composite artifacts... but other cores? Which ones do you think would benefit from that?

I wonder if Amiga virtual karting 2 would work on LCD. Probably not.

Newsdee wrote: ↑Fri Dec 04, 2020 7:55 am It was really needed on Megadrive since some games rely heavily on composite artifacts... but other cores? Which ones do you think would benefit from that?

https://www.youtube.com/watch?v=5rtTZh7F9m0

Metal Warriors on SNES is an example of one of the few SNES games that prominently used dithering.

The upcoming PS1 core (still in somewhat early development where more people are getting involved, after 2 years of amazing hard work by Laxer3a) will likely have a DIP switch for dithering on and off (it's already incorporated in the current code, which isn't natively running completely on the MiSTer yet, but many components of it are currently being ported over), I'm not aware of plans for composite yet though.

Newsdee wrote: ↑Fri Dec 04, 2020 7:55 am It was really needed on Megadrive since some games rely heavily on composite artifacts... but other cores? Which ones do you think would benefit from that?

Really, I just like the way it looks. Composite Blend is like putting on a literal pair of rose-colored glasses; it hits me with waves of nostalgia. It just looks great, that's all. It's certainly not needed.

Newsdee wrote: ↑Fri Dec 04, 2020 7:55 am It was really needed on Megadrive since some games rely heavily on composite artifacts... but other cores? Which ones do you think would benefit from that?

Don't know if the core has room for it but ao486 would be nice to have a CGA composite blend

SNES and ao486 cores are somewhat comparable in size with the SNES using around 75% of the Cyclone V in the DE10-nano and ao486 using about 81% (this could be outdated info though, likely is). This will give you an idea for the stuff that had to be done for composite blending on the Genesis core.

https://github.com/MiSTer-devel/Genesis ... tl/cofi.sv

This is the composite blending system verilog file that Kitrinx made.

https://github.com/MiSTer-devel/Genesis ... is.sv#L204

This is the line that had to be added (in addition to the space made/reserved for the Status Bit above) for the option to be selected in the OSD.

Finally, most of this had to be added, just to give you an idea:
Among other things I'm sure.

EDIT: Here ya go, found the original commit by Kitrinx.

https://github.com/MiSTer-devel/Genesis ... 386db8d7d4

Then ElectronAsh submitted this series of PR's I believe:

https://github.com/MiSTer-devel/Genesis ... 134724e8c8
https://github.com/MiSTer-devel/Genesis ... 51bd2a0b8e
https://github.com/MiSTer-devel/Genesis ... 3edf8d1f2a

Hopefully this will help anyone curious or motivated to work on it, to work on it

I feel the hardest part is justifying the use of an extra entry in the OSD menu Maybe it can be used to replace the HQ2X option?

Newsdee wrote: ↑Thu Dec 10, 2020 3:13 am I feel the hardest part is justifying the use of an extra entry in the OSD menu Maybe it can be used to replace the HQ2X option?

NOOOOOoooooooooo.......!

Newsdee wrote: ↑Thu Dec 10, 2020 3:13 am I feel the hardest part is justifying the use of an extra entry in the OSD menu Maybe it can be used to replace the HQ2X option?

I hope you're trolling lol because I use think the combination of HQ2X with the Scanline (sharp) filter is the best way to play console games, and HQ2X with LCD (Gameboy) is the best way to play handheld games. The GB and GBA cores look stunning with these two options, and the consoles have that classic CRT look while also rounding out the pixels.

The Genesis composite blend is stunning, I can't get how amazing it is. It's like composite 2.0...I'm starting to find it's better than my original MD with RGB. Would definitely love to see it on all cores. I've been told it was taken advantage of by some NES games too?

On a different note, I feel like it's a bit too strong for 256 res games, it would be great to see a strength setting or specific 256 option.

*shrugs* It was a big part even of the C64 and 8-bit Ataris. It was basically an early form of dithering, and was used to great effect by many pixel artists of the day.

Definitely doesn't make sense for all cores. Only handful for the systems that used dithering heavily.

SegaSnatcher wrote: ↑Sun Jan 10, 2021 5:43 pm Definitely doesn't make sense for all cores. Only handful for the systems that used dithering heavily.

We don't need it. Just like how it looks. If this could be achieved with a filter, I'd be game for it. The composite blend on this core specifically though, looks a million times better than the Blargg filter on things like RetroArch. Tossing on the Composite Blend and some scanlines, and I'm back in my childhood. I love it, and I'd love it on all non-handheld cores, regardless of dithering usage on the other systems.

MadDog wrote: ↑Tue Jan 12, 2021 6:23 am

SegaSnatcher wrote: ↑Sun Jan 10, 2021 5:43 pm Definitely doesn't make sense for all cores. Only handful for the systems that used dithering heavily.

We don't need it. Just like how it looks. If this could be achieved with a filter, I'd be game for it. The composite blend on this core specifically though, looks a million times better than the Blargg filter on things like RetroArch. Tossing on the Composite Blend and some scanlines, and I'm back in my childhood. I love it, and I'd love it on all non-handheld cores, regardless of dithering usage on the other systems.

You could just use a heavy filter in the custom video filters option.

Just wanted to say that composite blend looks excellent on old Nec Multisync 2A. I thought the composite blend looked too blurry on 19" CRTs but for some reason it is just perfect on this old 14" VGA monitor. It seems that monitor does matter and newer is not necessarily better than old.

https://www.chrismcovell.com/gotRGB/rgb_compare.html

Adding in some other examples that are not just on the Sega Genesis, some of these just have to do with palettes though, rather than composite blending necessarily.

Blaster Master is the most striking example on the NES.

SegaSnatcher wrote: ↑Sun Jan 10, 2021 5:43 pm Definitely doesn't make sense for all cores. Only handful for the systems that used dithering heavily.

Any system that used composite or RF for video output will have had games that make heavy use of dithering. That was certainly never a Genesis only thing.

I see Jotego added something similar in his arcade cores called 'Old TV'! Love it! Looks great!

I do notice some composite blend filters now, think they are under the comp folder or something (maybe inside misc?) The scanline variants can look pretty decent at 4x.

FoxbatStargazer wrote: ↑Sat May 08, 2021 2:30 am I do notice some composite blend filters now, think they are under the comp folder or something (maybe inside misc?) The scanline variants can look pretty decent at 4x.

I tested those filters. Sadly they do not achieve a composite blend effect: viewtopic.php?f=22&t=196&p=25475#p25475

dmckean wrote: ↑Sun Jan 24, 2021 10:52 pm Any system that used composite or RF for video output will have had games that make heavy use of dithering. That was certainly never a Genesis only thing.

Can you find me an example on NES where it look notably incorrect without being composite? 2600 and Turbografx also if you have time. SNES is high colors so its not going to be needing this. SMS is RGB, but maybe you can throw that in there if there's a good example. I'm struggling to find any good examples of why adding another step to the video chain is necessary.

Kitrinx wrote: ↑Sun May 09, 2021 1:00 pm Can you find me an example on NES where it look notably incorrect without being composite? 2600 and Turbografx also if you have time. SNES is high colors so its not going to be needing this. SMS is RGB, but maybe you can throw that in there if there's a good example. I'm struggling to find any good examples of why adding another step to the video chain is necessary.

Not the person you asked, but maybe this helps: You can find an argument for composite, with example for a lot of systems in these blog posts:

• http://nerdlypleasures.blogspot.com/201 ... osite.html
• http://nerdlypleasures.blogspot.com/201 ... ourri.html

I would not call pure pixels perfect or Composite Blend "correct" or "incorrect", but options that reflect how these systems were used and looked on certain hardware. Some wanted the blending effects that were often utilized in graphics design for games, others wanted a way-above-the-norm sharp and pixel perfect image display and did not mind losing the blend effects.

Threepwood wrote: ↑Sun May 09, 2021 1:13 pm

Kitrinx wrote: ↑Sun May 09, 2021 1:00 pm Can you find me an example on NES where it look notably incorrect without being composite? 2600 and Turbografx also if you have time. SNES is high colors so its not going to be needing this. SMS is RGB, but maybe you can throw that in there if there's a good example. I'm struggling to find any good examples of why adding another step to the video chain is necessary.

Not the person you asked, but maybe this helps: You can find an argument for composite, with example for a lot of systems in these blog posts:

• http://nerdlypleasures.blogspot.com/201 ... osite.html
• http://nerdlypleasures.blogspot.com/201 ... ourri.html

I would not call pure pixels perfect or Composite Blend "correct" or "incorrect", but options that reflect how these systems were used and looked on certain hardware. Some wanted the blending effects that were often utilized in graphics design for games, others wanted a way-above-the-norm sharp and pixel perfect image display and did not mind losing the blend effects.

Of those examples on that page, only genesis appears to require it.

SNES high res mode of course is already handled by the core, and DKC that example looks simply awful compared to the clear one, and I see nothing there that is improved by applying composite. For DKC using a soft scanline filter is a much better option.

Kitrinx wrote: ↑Sun May 09, 2021 4:29 pm Of those examples on that page, only genesis appears to require it.

SNES high res mode of course is already handled by the core, and DKC that example looks simply awful compared to the clear one, and I see nothing there that is improved by applying composite. For DKC using a soft scanline filter is a much better option.

Well, "better", "improved", "correct" and "incorrect" are all subjective and lie in the eye of the beholder. A sharp, pixel perfect image may be high fidelity to one person, but raw and incorrect to another.

Likewise, while I believe that the linked blog posts make some good arguments, with evidence taken from the real systems on CRTs, for composite blend, that does not need to hold true to everybodies taste. There is simply not one way to "do it right".

Hence why the software emulation community creates filters like the CRT-Royale shader. It's about having choices on modern hardware, because CRTs are no option due ot the fact that they are dying out.

A good bunch of people have expressed their admiration for the work you did on the Composite Blend option and would love to have this in all cores, because it is much closer to how the systems actually looked on consumer hardware.

But well, as said, in this case what is better is subjective.

Kitrinx wrote: ↑Sun May 09, 2021 1:00 pm

dmckean wrote: ↑Sun Jan 24, 2021 10:52 pm Any system that used composite or RF for video output will have had games that make heavy use of dithering. That was certainly never a Genesis only thing.

Can you find me an example on NES where it look notably incorrect without being composite? 2600 and Turbografx also if you have time. SNES is high colors so its not going to be needing this. SMS is RGB, but maybe you can throw that in there if there's a good example. I'm struggling to find any good examples of why adding another step to the video chain is necessary.

All the composite dithering in backgrounds in Little Samson is the only one I can think of off the top of my head. I'm sure there's probably others though.

dmckean wrote: ↑Sun May 09, 2021 5:39 pm
All the composite dithering in backgrounds in Little Samson is the only one I can think of off the top of my head. I'm sure there's probably others though.

I was unable to locate the part you are talking about.

Threepwood wrote: ↑Sun May 09, 2021 5:15 pm
Well, "better", "improved", "correct" and "incorrect" are all subjective and lie in the eye of the beholder. A sharp, pixel perfect image may be high fidelity to one person, but raw and incorrect to another.

Likewise, while I believe that the linked blog posts make some good arguments, with evidence taken from the real systems on CRTs, for composite blend, that does not need to hold true to everybodies taste. There is simply not one way to "do it right".

Hence why the software emulation community creates filters like the CRT-Royale shader. It's about having choices on modern hardware, because CRTs are no option due ot the fact that they are dying out.

A good bunch of people have expressed their admiration for the work you did on the Composite Blend option and would love to have this in all cores, because it is much closer to how the systems actually looked on consumer hardware.

But well, as said, in this case what is better is subjective.

There are certainly tastes involved in the output of video, however in an objective context, one qualify something as broken or not broken in the sense that it looks a way that is clearly unintended, like the stripes in genesis or the lines in tower toppler on atari 7800.

While subjectively you might like a softer or sharper picture, minor video adjustment is the responsibility of the video filters or your television to achieve, not the core, unless it is explicitly repairing an otherwise unreconcilable problem. Other than the systems which already have blending, I haven't seen any pictures of games that clearly look distorted without the feature. That is what would warrant adding the additional burden to the video path in my mind. If someone can show me some pictures that clearly look *wrong* without it, I will add the feature for compatibility with those games.

I don't think anybody is saying that something is "broken" without this option. It's just that it would simply make a lot of people happy. It's not really about these few oft-brought up examples of particular artifacting, and there is no way to recount all the intended examples of devs using it intentionally, althought it stands to reason that there must be many more of them. Regardless, the fact remains that vast majority of users in the Eighties connected their machines to CRT displays via either RF or composite (some, myself included, even in the Nineties). S-Video or RGB was either unavailable, or a luxury. So, no wonder that many people these days seek to replicate that particular look.

Seeing as MiSTer doesn't do advanced shaders, and there are obviously no such things in modern TVs, composite blend seems to be a very strong alternative, better than the already available filters. It would be great to have it as an option on most of the cores from that era, that's all.