4K - Sega Astro City, Sega Blast City Nanao & Sony KV-32XBR48

RetroArch Additions Shaders
#1

:rocket: UPDATE May 21, 2026: v35 — The Holy Trinity - Asto City-Blast City-Sony KV-32XBR48 Final

The Master Pack is now complete and v35 final is up on the Github as a release. Includes NEW built from the ground up Luts for each CRT. V35 also fixes a packing error that made its way into v34. There will be other projects in the future, but these three Iconic CRT’s are now complete. Have Fun!

After an extensive collaborative and empirical development loop, these presets are optimized specifically to overcome the unique physical challenges of displaying high-fidelity CRT shaders on 4K self-emissive WRGB WOLED panels (specifically targeted on a Sony KD-55A85 display). These are for 4K displays only (at 1080p the resolution with collapse (blurry/a bit washed out)). Also, you should set all systems to Vulkan, where possible.

Rather than chasing a mathematically sterile “digital stencil” lookup, these configurations focus on using the crt-guest-advanced core to replicate the actual analog, thermo-chemical imperfections that gave these legendary monitors their unique, organic three-dimensional pop.

Key Architecture Accomplishments:

  • WRGB Phase Correction: Traditional shaders are built for flat RGB/BGR LCD pixel structures. The physical presence of the White (W) subpixel gate on LG Display WOLED panels introduces a horizontal spatial offset that creates harsh color fringes and flattens screen depth. These configurations utilize precision-tuned horizontal phase windows (12% for the Sony Grille, 20% for the Nanao Honeycomb) to absorb this offset, allowing the light to bleed organically to mimic true phosphor bloom and glass refraction.
  • Symmetric Phase Alignment: smoothmask is held tight to prevent downstream back-pressure from distorting the color volume. Instead, s_sharp is used strictly within the horizontal signal plane to cleanly suppress non-integer horizontal aspect scaling waves (such as the PC Engine’s 256px columns stretched to 4:3) without causing any vertical scanline row bleeding or contrast loss.
  • Protected First-Glow Color Chemistry: Includes custom-built 1024x32 3D Identity color LUT cubes mapped to real NTSC-J (Arcade P22 phosphors) and cold Sony broadcast colorimetry. These load natively inside Pass 5 (LinearizePass) and are entirely insulated from downstream clipping, maintaining profound saturation levels.
  • High-Fidelity Grid Alignment: Utilizes custom viewport coordinate mapping to bypass standard intermediate texture down-sampling. This locks the internal frame rendering to full-resolution presentation boundaries, forcing the subpixel mask triads to align cell-for-cell with absolute, uncompressed pixel bite.
  • Insulated Pipeline Processing: Structural optimization chains the multi-pass layout to run in a strict forward-facing sequence. This protects our custom color chemistry profiles early in the data transit, completely eliminating mid-stream compression to prevent highlight clipping and keep scanline trenches frozen into ink-black contrast voids.

Profiles Included:

  1. Sega Arcade Astro City (Nanao MS9-29): Built around a 4K Honeycomb Dot-Mask ( shadowMask 6 / masksize 2.0 ). Soft vertical scanning focus models the dynamic raster spot behavior of an open arcade chassis to maximize 3D asset mass.
  2. Sega Blast City (Nanao MS-2931): Built around a high-density fine-pitch 4K Honeycomb Dot-Mask ( shadowMask 6 / masksize 2.0 ). Locks tight, hard-edged vertical beam boundaries to wrap every colored cell with distinct micro-contrast outlines. This delivers an intense stereoscopic 3D optical pop. It forces high-frequency 24kHz/31kHz progressive arcade vectors and early 3D polygons to resolve with absolute edge sharpness. High-voltage cathode drives run un-clamped to replicate peak hardware luminance without crushing low-IRE shadow gradients.
  3. Sony Broadcast KV-32XBR48 (Super Trinitron): Built around a native 1:1 Aperture Grille layout ( shadowMask 10 / masksize 1.0 ). Utilizes a deep vertical scanline focus trench ( gsl 2.0 ) alongside a simulated Beam Current Limiter (BCL) luma governor to preserve high-rigidity broadcast text clarity without digital highlight clipping.

GitHub Repository:

Note: The Github contains full instructions on how to install and use includes all files needed, including the version of Guest that is needed for these shaders (It is important to use the version of Guest as per the Github, as other versions may break the shader code).

:rocket: UPDATE May 21, 2026: v35 final released

For the full technical breakdown of our high-voltage luma curves and display parameters, check out the main repository README.

Grab the complete standalone v35.0 zipped pack from Release Page on Github.

6 Likes
New CRT shader from Guest + CRT Guest Advanced updates
#2

Looking forward to some screenshots and photos of the screen and a little less technical technical breakdown of your solution to the WOLED/RWGB subpixel offset issue. Also, if it is that you do have a definitive understanding of the problem and a solution for this white subpixel interfering with the alignment of the R-G-B triads anomaly, is it possible that you can apply this knowledge to solve the similar problem that 4 Stack RGB Tandem OLED has with its BWRG subpixel layout?

1 Like
#3

who sticks a white sub pixel right in the middle?..Oh, wait :slight_smile:

I’ll pm you.

1 Like
#4

Right. So, whilst shaders are built using maths, so what right? As they say, an image is worth a 1000 words…

Right click image>open image in new tab, click again for full size/zoom.

:joystick: SECTION 1: Arcade Reference Monitors (15kHz / 24kHz / 31kHz Multi-Sync)

This section merges our custom, high-fidelity Japanese arcade monitor presets, leveraging 4K Honeycomb Dot-Mask simulations for authentic visual performance across all frequency ranges.

  • Sega Arcade Astro City (Nanao MS9-29): Optimized as the 15kHz Low-Resolution King. Features soft, organic 240p/480i curved CRT simulation, emphasizing watercolor phosphor bleeding and scanline blending for classic 2D content.
  • Sega Blast City (Nanao MS-2931): Calibrated for medium 24kHz and high 31kHz progressive scan paths (Model 1-3, NAOMI, 480p). Features sharp, tight vertical beam boundaries for maximum contrast and distinct, high-resolution geometry definition.

:joystick: ASTRO CITY

Here is a link to Raver Racer, so for anyone that is curious, you can zoom in to see the Triad layout in action with the shaders maths applied in Astro City:

:joystick: BLAST CITY - All core outputs at native, zero upscaling

Blast City: 800% Zoom -

image
image3801×1881 1.08 MB

:tv: SECTION 2: Home Console Broadcast Monitors (Aperture Grille)

Targeting premium, high-rigidity consumer and broadcast televisions.

  • Sony Broadcast KV-32XBR48 (Super Trinitron): Built around a native 1:1 Aperture Grille layout (shadowMask = 10.000000 / masksize = 1.000000). Utilises a deep vertical scanline focus trench (gsl = 2.000000) alongside a simulated Beam Current Limiter (BCL) luma governor to preserve high-rigidity broadcast text clarity without digital highlight clipping.

IMAGES COMING SOON

5 Likes
#5

These look really good to me. Maybe a little too much glow in some of the pics, but some people like that. I’m not much of a shader expert, but I think they are impressive.

1 Like
#6

Does the Trinitron_Lut have to overwrite the one in the Guest Advanced LUT folder?

#7

I was about to about update the 1st post. You need to install as per the instructions on github. V32 release is available as a single download, containing the shaders and custom made Luts (it also includes the correct version of Guest to use, to make there is no Guest version mismatch that may break the shader code).

#8

Looks really good, would love an LCD version

1 Like
#10

:loudspeaker: UPDATE May 18, 2026: Milestone v33.0 is officially LIVE! Added native 4K LCD support.

#11

It’s on my list for this week. - UPDATE - Done.

1 Like
#12

So, the blind spot here, or. the one other CRT shader that ties everthing together, is the equally infamous - Sega BlastCity Nanao MS2931…deep dive initiated. Please stand-by for the next transmission. :slight_smile:

#13

Progress update: Sega Blast City Nanao MS2931 — v34.0 [The Analog Absolute] will be finished in the next 1-2 days. It fits nicely into the pack, as it’s for hires games - Arcade: Virtua RacingVirtua Fighter/Noami etc etc. Consoles: Dreamcast/Gamebube/PS2 (lrps2 vulkan) etc etc.

I have to say, I’m very happy with it.

3 Likes
#14

:rocket: UPDATE May 20, 2026: Milestone Release v34.0 is LIVE!

The Master Pack has been expanded on our GitHub repository with the inclusion of our new Sega Blast City Nanao MS2931 presets.

#15

Screenshots of Sega Blast City Nanao MS2931 added to post 4 above.

#16

:rocket: UPDATE May 21, 2026: v35 — The Holy Trinity - Asto City-Blast City-Sony KV-32XBR48 Final

The Master Pack is now complete and version 35 final is up on the Github. Includes NEW built from the ground up Luts for each CRT. V35 also fixes a packing error that made its way into v34. There will be other projects in the future, but these three Iconic CRT’s are now complete. Have Fun!

1 Like
#17

:rocket: **UPDATE May 22, 2026: v35 — Brand NEW Lut creation engine built

For anyone that downloaded v35 final from the github release page, I would advise to delete your intalled copy and re-download the modifed v35. Whilst we we were 100% happy with the shaders, the Luts were about 95%, because of the base maths in the Lut creation engine. This has now been entirely rebuilt from the ground up, with brand new Luts created for each of the 3 shaders.

I don’t have time today to update any documentation on here or on the github, or the main code on github (i’ll do that tomorrow), but all the upated code is in the new v35 release here: https://github.com/oldpainless1234/Oldpainless-CRT-Shaders/releases

6 Likes
#18

Sorry, my post was not meant to be posted. I’ll be working through the new shader in private. It was too soon, and we want to get this brand new shader engine 100% correct — for clarity, this is not a stacking tweak, but an entirely new 13th base shader built from the ground up.

2 Likes
#19

You should work with HSM to get this included in MegaBezel for whenever the next update is.

#20

WIP…

image
image3290×162 22 KB

Turns out, for the path we are heading down…you need, harmony.

2 Likes