Thanks!
Indeed reproduced, but I’ve a workaround ready.
I’ve just to test the performance impact before merging.
Also, I spotted that the vignette/pillow/screen uniformity thing does not follow the tilt “perspective”, so I’ll fix that too.
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Workaround applied and vignette perspective fixed, you can pull from the git repo.
Pillowing effect still needs some attention, instead.
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tldr:
If you update from the github repo and see the slotmask disappear from your tweaked personal presets, divide “Clears hives patterns (slotmask)” by "Phosphors height min->max gamma"
Why?
Regarding the “clear hives patterns” parameter, used to mitigate slotmask glitches at low resolutions:
…there has been some changes on the development repo that requires you to modify any preset using it.
Shipped presets have already been tweaked, but if you need to, the formula is:
slangp parameters:
new PIXELGRID_Y_MASK_OFFSET_DEHIVE = old PIXELGRID_Y_MASK_OFFSET_DEHIVE / old PIXELGRID_GAMMA_H
Human readable:
New "Clears hives patterns (slotmask)" = old "Clears hives patterns (slotmask)" / old Phosphors height min->max gamma
This change not only provides a small performance improvement, but makes the dehive appearance independent from the Phosphors height min->max gamma parameter, so it is a win/win
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If what you are trying to do is change the image, you will need to save a preset and add a new background image line to it.
You would really be better off starting with one of kokoko’s presets unless you need one of my custom bezels.
These, and my custom backgrounds, are what my project is all about.
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Hi there what’s currently the best way to add your own backgrounds? Thanks 
Uhm, I think the easiest way is to load the preset you want as a base in retroarch, then save it as a simple preset.
Open the saved one with a text editor and add the line:
bg_under = /path/to/your/image.png
and
bg_over = /path/to/your/image.png
Save and load the modified preset.
From there on, you may need to align/zoom the picture.
Search for “Backgound image:” in the docs, for additional details:
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Ok brill thank you… does it work well with the wildcard system?
I never tested it much, but there is no reason why not.
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In that case I’ll go through the uborder presets I have and swap em over to koko just to see how they look 
… see if I can get the ambi working over the bg the same 
… I think the uborder use the standalone koko ambi iirc.
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Yeah, I think ambilight in koko-aio has some extra settings regarding the blending mode and the alpha channel managment, so maybe the look would not totally be the same without some extra tweaking.
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It’ll keep me busy this afternoon while my missis watches great British bake off 
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Hi m8 great shader! i have the new background image saved as bg_under/over. What is the best way to have the ambi-light go over the background image. Thanks
Since there are multiple ways to approach this with different results, there isn’t really a single “best” one 
What’s your end goal? Have you had a chance to go through the docs yet?
One of my fav. presets when it comes to ambient lighting is Monitor-Ambilight-immersive:
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Shortly, a sort of tweaked halation/global illumination effect will be available as a suboption of the bloom section:
It works by taking a very much blurred version of the original image and apply its brighter tones to the final image, thus colorizing it.
At its maximum strength it looks like this, showing just to make it evident:
But on a normal use, it gives “breathing” and produces nice subtle shades:
To avoid too much brightness, bloom and halation are compared and just the maximum will be used; also the option to apply less bloom to bright areas applies to halation too.
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Hi, I’ve analyzed the shots and compared them to my recollection of real CRT appearance and behaviour and this method of enhancement only seems to work for darker colours.
On darker colours it looks like a subtle glow emanating from the phosphor core, however on brights, it just looks like WOLED’s white subpixel washing out the colours of the phosphors.
Maybe it might work better if there were a steep roll-off or cut off where the white is visible because remember none of the phosphors were white as well.
So it looks like a miniLED LCD with white backlight glowing which doesn’t blend well with the original phosphor colours. At white and brighter colours, colour saturation of the phosphor doesn’t decrease as we’re seeing here. On the contrary, it’s supposed to be at its maximum.
If we could get this right, I think that we can finally simulate bloom and glow without sacrificing accuracy.
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Yes, what you say sounds totally right to me.
A stronger light from behind the glass should have the precedence over the light scattering in CRT glass and should pass as is.
However, the final effect is not as pleasing (trying it is trivial, but performance wise is heavier):
That way halation flattens the image, while applying globally gives me the impression of added depth.
Also, as a mitigation:
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All of this is why we need to embrace the hybrid approach of leveraging the brightness advances that have been made in TVs in recent times.
So how long do we have to wait until approaches that don’t wash out the phosphor become more of the norm, rather than the exception?
What would it look like if it took a very much blurred version of the original image after it has been represented by an RGB phosphor mask and applying the brighter tones of the glow to the outsides of each phosphor creating a halo around each phosphor that is in the same colour of each phosphor?
Assuming the rgb mask represents the original image with accuracy, its blurred version will be the same as the blurred original image without the mask.
I don’t think that the halation effect is something one would like as is.
I’m picturing something different in my mind. I’m visualizing soft red, blue and green halos around each phosphor, with no white anywhere, except if viewed from an appropriate distance. In other words each phosphor being blurred individally.
I think it would only look the same if the blurring is at an extreme level but it has the potential to provide an individual glow effect to each phosphor without the washing out effect because the glow would be the same colour as the phosphor it surrounds.
The 2 looking the same might depend on other factors such as display resolution and TVL of the emulated phosphor mask. i.e. it might work better if we have higher display resolution and lower TVL CRT resolution.