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pokefan531 · 2 months ago

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Handheld LCD Shader Projects

Welcome to the introduction of a collection of the handheld LCD shaders that emulates the colorspace and LCD metrics from the offical handheld gaming consoles. Ranging from Gameboy Color to the PSP being the main focus for emulating the displays from their colorspace to specified gamma and color temperatures. Most users would be playing Gameboy Color and Gameboy Advance in raw RGB on emulators as well as on the Gameboy Player, and that's totally cool. Playing these games on the backlit displays have been much easier to see the game you're playing than ones without any light on the LCDs. Heck, even having much better contrast that gives off darker blacks, or even perfect blacks from OLEDs. However, once you start playing some of those games, you can really see something off from those games from your childhood handheld consoles, most prominent, the Gameboy Color and the Gameboy Advance. Those screens are really different from modern displays we use on a daily basis, on every single specifications. GBC and GBA would look too saturated and odd color hues in a lot of games, under raw RGB picture. In GBA's case, a lot of games can have lighter gamma that looks overbrightened in raw RGB, since those were only calibrated for the old GBA screens that has darker gamma. Oversaturation from those games were also calibrated for these older displays that has less saturation. This project is meant to replicate the colors and gamma from the real console model, to any project, such as emulators, Gameboy Interface, scalers like the Retrotink 4K, LCD mods, and HDMI/FPGAs projects. It would allow users to pick any shaders or LUT textures to replicate the LCD color display to your preferred way to play games beyond pure original hardware. Of course, there is also Nintendo DS from the first model, the DS Lite, Gameboy SP AGS-101 (Backlit version), Gameboy Micro, and the PSP on its first model, as of current. The project is also meant to preserve the display data and metrics from those handhelds.

(GBC shader preset with default settings)

(GBA shader preset with default gamma, and LUT set to "2" for colder greyscale)

(NDS shader preset with default settings)

(PSP shader preset with LUT set to "2" for PSP's known colder greyscale)

Downloads:

Instructions: If you haven't already installed shaders, do so inside retroarch under slang shaders. After downloading my package, extract the zip file to "shaders_slang" inside Retroarch's shader folder. It can be implemented inside libretro's shader once the slang shader pack gets updated. I suggest loading the shaders by presets, under .slangp, in both Handheld and Reshade folder (latter being under the handheld-color-LUTs folder). Presets inside handheld folder has switchable settings, including presets containing LCD shaders. Presets inside reshade only loads in LUT textures rather than just shaders. Useful for emulators or projects that only loads in LUT textures as their only filter.

The shaders is based on HunterK's shader, Color-Mangler from the misc folder in slang shaders from Libretro, which was made from a help for my project. It defaults to sRGB on the shader's option for many average users. A shader preset from Handheld folder has LUT choices to change the greyscale color temperature replicated from the real handheld console. GBA one can adjust the gamma to make the image darker, while GBC and GBM has gamma option to brighten or darken. In Reshade, it only had adjustable greyscale temperature except for GBA_GBC variant. The shader supports DCI-P3 and Rec2020 colorspaces on its option to use on your display that may support either of those to reach better color saturation to present more accurate blue primary color from my shaders that common sRGB colorspace is limited from. The GBA and GBC have external gamma options to adjust the gamma on the greyscales if not using any LUT shader preloaded.

Developer notice: For developers of any GB/GBA (or any handheld) projects involving emulators, FPGAs, or screen mods, shall take some advices when it comes to implementing the shader or color filter to your projects. To implement as a shader, the gamma has to be lower first by 1/2.2 (Can be used to change the GBA gamma itself to darken the screen), then use my color values from the shader to change the color primaries, and then revert the gamma by 2.2 afterwards to have great color correction while respecting luminance and color tones. Also I prefer if you take color values from white balance correction that are outside of GBC/GBA shader. For only LUT texture, a more easy approach for devs, I prefer using the non-cold variants if preserving the greyscale color tone. GBA and GBC LUTs have their gamma and greyscale adjusted to emulate the screen's default gamma. If you only want just the color gamut correction as an LUT, use the GBA_GBC variant inside Reshade's LUT folder. -If you decide to implement a basic GBC or GBA colorspace to the emulator, use the sRGB data. The gamma change must happen before the color correction. -If the project is aimed for TV such as Gameboy Interface or GBA Consolizer, use the sRGB LUT shader, since SD and HDTV resolutions aim for sRGB colorspace. -If the FPGA such as Analogue Pocket, IPS screen mods, or emulation device uses a display gearing towards sRGB colorspace, use the shader, color filter, or LUT accordingly. -If the OLED screen mods or emulation devices have its native colorspace target around 100% DCI-P3 Volume, use any filter accordingly. -If implementing the shader to your emulation project, do port the shader to your shader or filter libraries. The shader and LUTs are in public domain after all, to spread about the color correction regarding GBC/GBA displays. -If using a professional scaler like Retrotink 4K with either GBA Consolizer or Gameboy Interface without any filters used, play with its gamut matrix settings for both GBC and GBA as "Red: 0.4925 0.3100" "Green: 0.3150 0.4825" "Blue 0.1625 0.1925" to emulate the color correction, and can be used on SDR or HDR mode to give out consistent image. Gamut info for other consoles below.

(Raw RGB, Gameboy Micro, and GBA shader with darken set to 0)

(Top: NDS; Raw RGB, DS-Lite, and NDS Phat)

(Bottom: GBA; Raw RGB, GBA-SP AGS-101, and GBA with darken set to 0)

Note: While DS-Lite and SP-101 are really close to sRGB that developers don't really need adjustments, it is shown to preserve on how far they reached from older models to newer ones in mid to late 2000s.

Story:

So when did I start the project and why I was invested in doing this? It was back in August 2014 when I first saw a forum on someone wanting to desaturate the GBA and mentioned the filters from emulators like VisualBoyAdvance, or VBA-M, as well as NO$GBA that has options to emulate the colorspace that is close to the real hardware. I was reminded how the latter emulator has those options when I used it long time ago. I mostly use unfiltered colors as that was how close it looks on my GBA-SP with "Better Screen" than the GBA. Yeah I actually have the backlit version of GBA-SP known as AGS-101. The display was a huge jump from old GBA to GBA-SP, as well as the Nintendo DS Phat under GBA. However, I had good amount of memories of playing my old GBA with the lights around me and I do remember the color saturation being very different overall. So I wanted to take a look on how to replicate the VBA-M's colorspace.

(Link to the forum I created of my histories of re-creating the GBA colors)

I first decide to use simple desaturation with a mix of shaders by playing with saturation and contrast levels. At first, it looks very similar to how VBA-M's attempt looked. That is, until I saw the blue color has a different hue, being more torqourise in VBA-M's recreation. Then a LUT shader appeared in libretro forums and I first used that for my photoshop to use crazy amount of filters to recreate the whole thing, even though it wasn't perfect, but close. Then I tried to replicate the original NDS model that I have for many years, and also played with the LUT textures from Photoshop. Yeah I just simply tried to copy the colors from the console, without any tools, on my uncalibrated old LCD TN panel screen, because I had such no experience on how colorspaces work, but it was worth a try. Then in 2015, I somehow found a shader that plays with RGB and I got help with Hunterk, a contributor on Libretro who has been involved with a lot of shaders for Retroarch. He made an amazing color mangler shader for me to put data of colors and gamma on the shader itself than just using a LUT texture. Then in May of 2015, I found another GBA on my house that was not used by a family for a long time. Yeah I lost my GBA somehow as a kid from another family, but a long story to tell. Thankfully I was allowed to use another GBA for full use just for this project. This was just the beginning of my progress on grabbing screen data starting with just a flashlight with my old LCD monitor. The only issue I always have is the common sRGB screens don't have deep blue colors that is needed for both GBA and NDS (and more), so I always had issues replicating the blue primary color. That's what got me to start learning about colorspace and what sRGB and color gamut means. And that's where my progress to get the right tools begins. I then later got a superior IPS 1080p monitor, the GBC, Colormunki Display, using DisplayCal and HCFR, Colormunki Photo, the PSP, GBA Micro, a 4K monitor, and a portable light to use on GBC and GBA. Now in 2024, I have really progressed with help of such tools I need, have become much better way of getting the LCD data from the handhelds to contain the color gamut, the greyscale, gamma, and color temperature.

So now the story is out of the way, here are the tools I used to gather infos from the handheld screens.

Samsung S80AU - A 4K IPS Monitor that supports DCI-P3 colorspace with great Delta Error scores especially for sRGB colorspace. It's also used to test out LCD shaders on a high DPI display. Colormunki Display - A Colorimeter that calibrates your display and gathers color data from your target screen. Colormunki Photo - A Spechrometer that behaves the same as Display, except gathers the white colors temperatures more accurately regardless on any type of LCD or OLED displays. It's used to make profiles for the Display to be calibrated for a specific monitors as the Display reads data much faster than Photo as well as reading darker blacks better. Displaycal has infos on colormeter matrix correction to add in why this combo is best used for serious color calibration. It's also used primarily for handheld console displays to sample color data. DisplayCal - Used to completely calibrate my monitor and other screens to give off pure sRGB colorspace with 6500K whitepoint. It's also used with its own ICC Profile creator to make .icc with given data from ColorHCFR for a specific Handheld Console display to emulate from. It's 3DLUT tool was also used to generate LUT textures to check the color and luminance on primary and secondary colors. ColorHCFR - A free alternative for Calman. It's used to gather data on the greyscale, the color gamut, and tons more info to check how your targeted display looks. It shows you graphical images of the screen's color gamut on the CIE diagram. MCH2 - A tool that used your generated DisplayCal monitor calibration data to create an .icc profile made for Windows 11 to convert the entire screen to your targeted colorspace such as sRGB and DCI-P3. G2 Pocket RGB Camera Light - A portable light that shoots out lights to use on handhelds that lacks any light, such as the Gameboy Color and Gameboy Advance. It toggles between RGB and pure whitelights with color temperature adjustments. It's used to match the whitepoint on both GBC and GBA to match my monitor's whitepoint as the closest. It's much better tool than me previously using my collection of phones to use the flashlight for color sampling, as GBC and GBA suffers from rainbowing, no adjustments on white balance, and less saturation by a flashlight, unlike proper lights like the G2 Pocket that eliminates those issues. 240p Test Mini - The handheld version of the well known 240p Test Suite. Used to check RGB, greyscale, motion flickering, and color scrolling on real hardware. https://github.com/pinobatch/240p-test-mini EZ Flash Jr - A GB/GBC Flashcarts to load ROMs and Homebrew for GBC and GBA. EZ Flash 3-in-1 Expansion Pack NDS - A GBA Cartridge to load in a ROM and homebrew in to load inside GBA and NDS. Used NDS to insert a ROM on its NOR memory. GIMP - A Photoshop-like image editor that is used to check generated LUTs from 3DLUT to check on the color values to adjust the shader. Retroarch - Using mGBA and Sameboy emulator core to check out the games while using the shaders I created for color correction. It also loads in image files for my best way to check out my shaders during adjustments.

(Top to Bottom: gba-color & gbc-color, gbMicro-color, nds-color, psp-color, DSLite-color, SP101-color, and raw RGB, all in sRGB)

Note: Why the white color is darker is due to clipping on the yellow color because of how color correction works with the blue color being out of sRGB gamut. Also, sRGB can't display those handhelds blue saturation due to it. Will soon post DCI-P3 and Rec2020 variants for displays that can see more saturation without internal color adjustments.

List of handheld consoles I owned to create shaders out of: Gameboy Color Gameboy Advance Gameboy Advance SP (AGS-101) Gameboy Micro Nintendo DS Nintendo DS Lite PSP (1000)

Nintendo Switch Online emulates GBC and GBA with their own color filters. GBA only desaturates the screen in more simple manner for sRGB, which was easy to implement. GBC, was very hard to do in shaders currently, so to use full experience, the LUT version can only be used to fully emulate the effect for other emulators.

I also found someone's Switch OLED data from a youtube video. The colorspace is taken with bigger saturation than even DCI-P3 when using vivid mode. Here's a link to the video by GamingTech:

youtube

I also made Palm Treo 700p shader long time ago by taking DisplayMate's data long ago while trying to translate the gamut pin points to HCFR since I don't have those in possession. I only made it for experiment long ago and only archived.

Replicating existing filters from emulators or dev tools such as No&GBA and VBA-M for GBA image replication, and GBC tools like Gameboy HiColour Converter V1.2 for GBC image replications. Even No$GBA and No$GMB docs had mentioned the LCD color differences:

(HiColour Convertor)

My Handheld LCD review datasheet and showcase for each platform (Coming Soon):

Gameboy Color Gameboy Advance Gameboy Advance SP AGS-101 Gameboy Micro Nintendo DS (Phat) Nintendo DS Lite PSP-1000

Handheld consoles I plan on getting and make data out of: PSP-3000 or GO PS Vita Nintendo 3DS (Owned, but not yet examined)

Handhelds I don't plan on getting or reviewing: Gameboy or Gameboy Pocket (Many have made their own shaders and filters out of their monochromic display) Gameboy Advance SP AGS-001 (Uses the same exact display as the original GBA except with frontlight added) Knockoff GB Boy Colour (I only allow any official handheld consoles for my project) PSP-2000 (Same colorspace and data as PSP-1000, except brighter screen) PS-Vita 2000 (Uses LCD instead of OLED, with less color gamut than original PS Vita) Nintendo NEW 2DS XL/3DS (or XL) IPS displays (Hard to find and a lottery to obtain; not common) Nintendo Switch (Owned and targets sRGB and its gamma well; whitepoint can vary between units)

Notes: On GBA, A lot of games are calibrated for the GBA's gamma due to how dark its screen's gamma looks. For some games, often Nintendo and a couple of companies with closest relationship to Nintendo, are adjusted for its colorspace. Certain games, often SNES ports, may have its original palettes on its setting. On GBC, many games were made for the screen during its run. It's unknown which amount of games weren't calibrated for the screen. Although certain games like Link's Adventure DX were completely adjusted for the screen on colorspace, gamma, and color temperature, which made purple-grey colors looks more grey overall. On both NDS and PSP, pretty often the first few years of games can be adjusted for those screens. Those are until both NDS-Lite and PSP-3000 have colorspace that closely aims for sRGB where no adjustments can be made. Many multi-ports for PSP of the same game from home consoles are very likely not calibrated for the first two PSP models. I didn't make a Switch OLED preset (from Vivid mode) with LCD shader, since the Switch OLED is not LCD, its RGB pattern is very different, and either original LCD or OLED are too high resolution to notice its RGB patterns. It's best to use only the shader to use with Reshade on a Switch emulator to emulate the OLED's vivid mode, but preserved in Libretro to see its effect. While I explain what the shaders are meant to use for, it's also your preference on using the shaders or just using the Raw RGB colors that fits your needs. You can use other color shaders on a GBA or GBC emulator, such as using NDS, Micro, or PSP shaders to your preference. The PSP shaders have much more saturation than any Gameboy line or NDS Phat, while preserving its hue.

To end off on this page, I would also like to give respect to other projects that tried their attempt to create their own color correction. While I prefer the best accuracy of the color correction from my shaders, many of their color corrections are pretty impressive with varying degree levels of accuracy, and they all motivate me to continue with the project to give out the best quality of color correction. Their blogs have pretty interesting ideas on how displays work on GBC and GBA.

(BGB's "Reality" Color Correction filter)

(GBCC's page on GBC screen tech notes)

(Bsnes/Higan Color emulation page)

(Gameboy Interface having their own Color Matrix correction, and including our shaders and filters alongside)