It streches the current mask by 1.5x horizontally. Mask sizes of 1.0, 2.0…skipped this ‘middle ground’ and there could be a small trade off rooting in modern display technology, but i guess it turned out quite nicely. 
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Yeah, I’ve now checked on my LG OLED TV as well and it’s indeed there. It’s visible while looking up and down on both your video and on Guest’s shader when configured for NTSC Composite.
It’s much easier to see on the OLED compared to my old LCD monitor.
It’s also visbile even when Sonic is standing still or the game is paused if you blink rapidly.
But all that looks like normal Composite temporal artifacts to me.
I’ve also tested the built-in Blargg Composite filter from GenesisPluxGX but the combing effect is completely missing from that implementation, even when doing frame stepping with K.
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I’m currently playing around with the scaled mask. It can look really cool, can also give a lot of new mask options, especially for 1440p users.
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Looks fantastic!! Does it work with 4k? Also which masks can be used with it?
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It can be used with any display resolution. Best looking masks are the ones with width 3 or 4.
Best to give it a try, see if it fits into a preset design.
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New Release Version (2023-05-17-r1):
Notable changes:
- two mask zoom factors are available now, 150% and 167%
- first works better with 2 or 4 width masks, second with 3 width masks
- small tweak to the slotmask mitigation code
Download link:
https://mega.nz/file/YsAWwCQb#M_fITRb-AsFCjb469pAQ4PbsFt5VdkWcdwwmZU_5qTI
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This sounds interesting. I’ll be checking this out later thank you.
Also @guest.r have you figured out what’s going on with the new grade not playing nice with your shader? Dogway suggests that grade should be the first pass, while I understand that I would also like to keep my presets the way they’ve always been with grade being the 3rd pass (I think it’s 3rd or maybe 4th) in my preset shader chain. It’s been working correctly that way up to now so I don’t understand why I would have to switch that up now. I would love to test the new grade out but I’m stuck before I can try anything.
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My color altering (and afterglow) shader passes are color neutral with default setting, so you can replace an early stock shader with the new grade without issues. It will run a notch slower, but barely noticable.
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Ok I’ll give that a try later. If worse come to worse I’m fine with just sticking to the old grade. Kind of didn’t want two sets of “color altering” shader passes in the chain even though yours gives neutral colors with default settings.
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New Release Version (2023-05-18-r1):
Notable changes:
- mask zoom overhaul
- each mask can be individually scaled up to 4 stages
- slotmask adaptation mode for mask scaling added
Each mask (width) likes it’s different scaling factor better, now this is implemented. Works very nice with most situations. Slotmask can be scaled by interpolation or just widened. I guess this brings more very nice mask options for different display resolutions.
Edit: small improvement
Download link:
https://mega.nz/file/o4JUGTKQ#BH_3jEtNW3JpMBOCegQozWwlG59qXYk-QKbzVrr5LTc
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Looking forward to trying this new feature. It seems like the best thing we never knew we needed until we saw it.
This might solve/enhance a couple situations at both 4K and 1080p for me. Situations where the Mask is either too coarse, leading to harshness and errors in rendering for example spikes, dots or colours appearing “outside the lines” of sprites or text or where the Mask is too fine, which makes it near impossible to appreciate the grid-like, textured appearance of the Mask itself at higher resolutions unless sitting very close to the screen.
Hopefully this middle ground would work just as well as its integer based counterparts in terms of subpixel awareness and accuracy (meaning the appearance of RGB triads won’t be affected).
Thanks again @guest.r for thinking outside the box!
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Very good, first of all to congratulate you on your work. I’ve been looking for my perfect shader for a couple of nights. Would there be a way to implement a system to modify the number of scanlines that appear on the screen? I find them very large and separated for my taste. Thank you.
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The number of scanlines is not an arbitrary quantity. it’s supposed to be half the number of vertical pixels in 240p aka double strike mode. You can alter the shape of the scanlines as well as the intensity of the gaps in between the scanlines.
There’s a highly integrated shader called Mega Bezel Reflection Shader which has something called fake scanlines and also Opposite Dir. Scanline Multiplier which allows you to increase or decrease the number of scanlines. This will negatively affect the quality of your rendering due to misalignment of scanlines as graphics would have been originally designed with the standard number of scanlines in mind.
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So now with the latest implementation how do I achieve a 167% Mask Zoom with, say, mask 6? Which value do I have to use? CRT Mask Zoom: 2?
Or for mask 10, for a 150% zoom, Mask Zoom: 1?
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@Cyber I have not completely understood 240p. Is it just doubling 240x2=480 and render even and odd numbers from frame to frame so you have this black gap between scanlines and maybe afterglow effect? And in the end 240p only supports 25Hz or 30Hz refresh rates? And if this is emulated with a shader vsync should be enabled for 60Hz output?
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Previous implementation had this issues / calculations. Now you can just increase the mask width (by 2.0 in your both cases, to answer your question) and an artifact free zoomed mask will be calculated.
Since the zoomed mask is wider, 150%, 167% etc. still applies to some situations, but now the optimal stretch is individually calculated for each mask and you can stretch/zoom the mask up to 4 additional widh size.
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Firstly, I’m not an expert on TV technology but without Googling this is my understanding of how 240p aka Double Strike works.
Normally in an NTSC signal you have about 480 lines of vertical resolution or 480 horizontal lines drawn on the screen every frame. This happens approximately 30 times every second. However not all of the lines are drawn at the same time. Half are drawn (the odd lines) then the other half is drawn (the even lines). This happens 60 times per second. Each half of a frame is called a field. So a typical 15KHz CRT display draws 60 interlaced 240 line fields per second.
In comes 240p/Double-Strike, its called double strike because instead of the beam aiming for the next line down each field, the beam draws over the same line for 2 fields then skips a line and draws the next line but since this is the entire frame that is being drawn not half of the frame it is incorrect to call these fields being drawn. They are actually complete frames being drawn, which is why 240p games on a typical 15KHz CRT actually run at 60fps, not 30fps.
The lines that the electron beam actually strikes are the scanlines while the black gaps which are the skipped lines are just the gaps in between the scanlines.
Many times people confusingly use scanlines to refer to both interchangeably.
https://www.hdretrovision.com/240p
https://junkerhq.net/xrgb/index.php/240p_video
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Thanks for explanation and video! Need to think about it. There are games like secret of mana which switch between interlaced and progressive output for text. If a shader emulates double dash with pronounced gaps it should check if progressive is used. If vertical resolution is always the half maybe something like „ if (res.x/res.y > 2.0) „ check could be used.
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