About a year ago i was trying to get correct colors in Retroarch for GBC and GBA games using your shaders.
GBA games came out looking great (gba-color.glsl + lcd-grid-v2.glsl is basically perfect, fantastic job), but i never found a good combo for GBC (the current results are all waaaaaaay too red). You may find the info that resulted helpful if you are working on the GBC shader:
And for a more current update/condensation:
Youtube capture from a video of someone playing on a real 1998 GBC: https://i.imgur.com/OuDjope.png
VisualBoyAdvance-M with Gameboy Colors: https://i.imgur.com/bUWoPBA.png
Gambatte w/ gbc-color.glsl (Color Correction core option off): https://i.imgur.com/Wws1Ft4.png
Gambatte w/ gbc-color.glsl (Color Correction core option on): https://i.imgur.com/vaonMTJ.png
Gambatte w/ gbc-dev.glsl (Color Correction core option off): https://i.imgur.com/geL3UaW.png
Gambatte w/ gbc-dev.glsl (Color Correction core option on): https://i.imgur.com/T8JpPw8.png
Not sure what type of LCD the reflective screens looks, but lcd-grid-v2 seems to look fine with default settings. I already did my project on a real GBC that I got nearly two months ago and did some research on it. I haven’t finished yet because I need much further tests on it. I also have very few librarys of gameboy games to show full main color primaries. I only got Red and Blue ones, but pur Green isn’t in the color picker from the bootstrap. All I can say now is that the screen is similar to GBA, but the gamma is different. I would explain it as a blog post to show what I mean.
On VBA, the color correction makes the screen have less contrast. On my early days in this forum, most users prefer seeing with full 0-255 range instead of what those internal color correction has looked. The blacks were more grey, and the whites are darker. On GB/GBC, VBA would make the gamma brighter and GBA darker. Also, the red is slightly down, but despite all this, they pretty much looked identical to what vba-color shader looks.
Both Sameboy and Gambatte’s fast color correction seems to not use gamma correction on the main primaries, which makes those pure colors appear darker than midtone colors. Sameboy pretty much keeps the saturation levels from pure RGB format, only blue is more torqouise. Also, it’s not a good idea to use those shaders with the emulator’s color correction enabled because it makes things more desaturated than it should. With GBC, depending on the light angle, usually above the screen, the gamma is lighter, so the grey ramps are brighter. It can play with how the midtone colors look.
As for my new GBC shader, made from scratch, it is not done yet. I made my own data for the gamma, and checking how the color primaries should look.
Ah. Well i look forward to seeing your new GBC shader in action when you finish it then (:
Great to hear a new GBC shader is in the works.
With what is currently available, what is the best combo of grid shader, color shader, and emulator for the closest picture to the real GBC?
For a long time, I finally have my hands on a real Gameboy Color. I decide to make a blog about it here.
GBC, just like the Gameboy Advance, uses the reflective light LCD instead of emitting light or having a light layer. It was still a big improvement over any original Gameboy and its variants. Like what My Life in Gaming showed on their Gameboy line video, the GBC have better response time and better contrast.
I ordered a GBC and recieved it few months ago and test it myself. The interlaced motion blur is there just like the GBA. The colorspace is similar, but something is really different. When played, the screen looks brighter. However, I flashed the GBC and GBA screen with a room light, and the white color has the same luminance. If both screens have the same brightness on the whites (or screen being turned off), it is related to the gamma. Both My Life in Gaming and the documents of No$GBA and BGB had said that the GBA screen is darker.
http://bgb.bircd.org/pandocs.htm#videodisplay (LCD Color Palettes (CGB Only) Section) https://problemkaputt.de/gbatek.htm#gbalcdvideocontroller (LCD Color Palettes Section)
It’s true that the gamma is darker, but the GBC is lighter. It is the opposite of how the GBA screen’s gamma worked. When you flash the light on the GBA, it depends on the angle of the light that is hitting the screen. When you have the light flashed on the bottom angle, it is really close to a standard gamma. If the light is shot at the middle 90 degree angle, the gamma has changed, and the GBA looks a bit darker when playing a game. On the middle angle, the dark areas are still seen pretty well. On the GBC, it becomes a bit brighter. When the light is going really above, such as having the sun or a light from the roof, the gamma shows a bigger difference. The GBA is darker that it’s sometimes hard to see dark areas, but the GBC looks brighter, but still can see all the highlights fine, and the dark areas are really bright. It’s really weird that GBC and GBA work in different ways. GB or GBC games looks fine on GBC. Some developers know that GBA is darker, even being different than the GBC.
Games like Shantae or Legend of Zelda Oracles of Age & Season have palettes for GBA. Those palettes looks like they have brighter gamma, just to have the palettes optimized for GBA. Later on in the lifespan, those games may look too bright when played on a Gameboy SP (AGS-101 backlit) or Gameboy Player.
It’s really odd that they made GBA’s screen work differently on gamma. It’s no wonder why the screen is known to look dark. It’s also the reason why developers didn’t need to worry about their games to look dark on GBC. However, the color space is different from most TVs and Monitors. It is less saturated, just like GBA. The colorspace is similar to GBA, but slightly different. As far as I have been trying to sample the colors to the screen, GBA seems to have slightly more saturation. Brighter gamma seems to make other colors brighter with less saturation, while the GBA is reverse. That’s how changing the gamma setting works. There is no real gamma value for each screens since it varies by light angle, but I can give the best values to show the best matched gamma when having the light from the top, the middle, and the bottom angles.
GBC-Color option has brightness values from 0 to 1.2. Top: 1.2 Mid: 0.5 Bottom: 0.0
GBA-Color option has darken values from -0.25 to 1.5. Top: 1.5 Mid: 0.45 Bottom: -0.25
When trying to flash the bottom on GBA, the gamma seems to be a little bit brighter than how the gamma is shown on emulators. It’s odd that the GBA gets the reverse effect of gamma variance from GBC, but it can have slightly brighter gamma than standard gamma if the light is shooting from the most bottom angle. If done on GBC, it doesn’t look dark, but it can have slightly brighter on the gamma, but since shoving the light on the bottom is more difficult due to its handheld design, I couldn’t determine the darkest gamma that I can recieve at best. However, the GBC can look close to Gamma 2.2, which can mean that the brightness can be set to 0.0 value if you prefer raw gamma. For the middle angle values, I don’t set the value to 50%, but around 30-40% on the strength. I tried matching them with the screen when trying to shoot the light in the middle angle.
I am aware that there are GBA games that do have different video setting when played on Gameboy Player. Games such as Super Mario Bros 3 have the palettes match the SNES Super Star game. Only thing I saw different in standard GBA mode is a simple gamma boost instead of also converting sRGB colors to GBA. Doom has only gamma adjustment, just like the actual original DOS game. Legend of Zelda games do have brightness adjustment, where the lowest one matches the SNES games. There are several more examples of GBA games that either has Gameboy Player enhancement to the video or have internal setting for the brightness. Sonic Advance 3 Gameboy Player mode looks a bit washout.
In the end, GBC shader looks really identical to the screen. Palettes matches more often between the screen and the shader. Of course, like GBA shader, GBC shader is also more or less absolute on colorspace. The blue is supposed to be more blue, but most screens target sRGB colorspace and the blue color found on GBC, GBA, NDS, or PSP cannot be completely replicated. The shades around the blue primary are pretty much clipped on the red value to have the other color tones match better. That’s how colorspace work when using icc profiles in relative or absolute mode.
(Bonus) On GBC bootstrap, if you pick Red/Yellow palette, it will look very identical on both GBC and GBA. How? The Red value is straight up pure red signal and the yellow is a straight up pure red and green signal. You can see it as 255,0,0, and 255,255,0, respectively. Because it is using the full signal on used colors and unused ones with no signal, it is not affected by any variance of the Gamma. That means regardless if you’re using GBC or GBA, and having different light angles shooting at the screen, it will stay the same. Only thing that will change is if how bright of a light shoots the screen, that’s the only thing it matters.
Next subject would be about LCD shaders. Well long time ago, I did play around with the settings for each preset that uses LCD-Grid-V2. I only made the RGB values at 0.75 and have gain at 1.5. It does not change the difference at all when comparing the default settings that has RGB values and Gain at 1.0. I was trying to see how I can have LCD shaders look bright enough without having clipping on the whites or looking too dark. Of course, it looks best when turning up the brightness of the screen. Well, that’s the only best option until majority of the users have HDR screens. Besides that, the Gamma has to be at 2.2 with Black Level and Ambient at 0.
Each handheld consoles have different RGB patterns. Some are RGB and others are BGR. Based on the consoles that I have, it’s best to look at an image that has very high contrast, like black and white to see what type of order the LCD is. Here are the lists:
GBC: RGB GBA: BGR SP-101: BGR NDS: RGB DS-Lite: BGR
I would like to include the PSP and old Palm phones in the list, but I don’t have those, and the latter have many models of it. To tell how the screen is RGB or BGR order, Have the white be the major part on the screen and look at the edge of the blacks or the sides. If the right edge of the screen is red and the left side is blue, then it is BGR. Same can be said for BGR if Blue and Red are reversed. I decide to change the settings on the preset based on the console’s screen.
The screens on GBC and GBA doesn’t look like it is interlaced like you would on a raw unfiltered interlaced content straight from a DVD. Instead, it looks like it has some sort of scanline motion blur. When moving up and down, depending on the speed, I can see some jagged edges, and even having a static image, you can see some scanline flickering on midtone colors or even grey. On NDS, all you only see is minor scanline motion blur. The PSP 1000 and 2000 has the longest response time I’ve ever seen on a portable device, the last time I saw it.
Now the last thing is to suggest which is the best LCD shader to use for GBC, GBA, and NDS. What’s best in my eyes that comes the closest is the LCD-Grid-V2 shader. I’ve tried the AGS and AGB shaders, but the subpixels are too thin and it looks a bit more dark than LCD-Grid. Sameboy or Simpletex shaders aren’t that close either. The white can pretty much reach above RGB just like normal screens. I’ve taken the snapshot of LCD shader to my phone that is 1440p, and compare it with my GBA-SP 101. It seems to look very similar on how the LCD shader looks. I even check on my GBC and it seems to match the shader providing that I use RGB order with GBC shaders on the top.
Best setup to emulate the screen is in this order: “LCD-Grid-V2 + GBC-Color” If you want to add motion blur, it goes like this: “Motion Blur + LCD-Grid-V2 + GBC-Color” Or course, you can change a specified colorspace from GBC to a different one, or not use it if you want to see pure raw colors like you would on AGS-101. The motion blur has to be first since it looks at the raw image only.
Now that I’m finished on the blog about the LCD screens from the real hardware of GBC, GBA, and others, here is the release for the shaders.
https://drive.google.com/open?id=0B5KxdoFEcyTkZ3I0WWZkM00zT0k
Soon: Shaders for BT.2020 and DCI-P3, for phones and Windows 10 HDR mode. Wider colorspace can show the blue color more accurately.
Updated the link. Default value for GBC-Color on CG and GLSL matches the slang version now. Both GBA and GBC have the default value at 0.5 for Darken Strength and Brighten Strength, respectively.
Incredible work again. I’m really fascinated by the screens and colors of the GBC and GBA, but lack the knowledge and dedication to do even a fraction of this. Your research and shader production and recommendations are of so much value. Thank you.
By the way, have you ever played around with a GBA Micro? To me it feels like Nintendo’s take on what the original GBA colors (as opposed to those of the AGA-101) should look like when combined with a backlit screen. It’s too bad GBC games are not supported by the Micro, but there is a way to get an idea of what they would look like on this screen and its colors by using the Goomba emulator on a Everdrive GBA X5 flash cart.
I don’t have it. It seems pretty expensive since it’s a rare console. Maybe someone who has it can use 240P test suite on the flashcart to show the Red, Green, and Blue color to collect the colorspace with a colorimeter like Colormunki Display or X1.
Good Day, sorry for not creating a new thread, but I’am a new user and not allowed to…
I’m not sure if this attempt is already been tested, but what if you take a game, where you know for sure, they had something in mind as they created the palettes; maybe all dark colours have the same lightness and saturation just the hue different. Or all light colors are a x steps lighter shade of a dark color. So we hope we find or know a game where they created a color palette with math to match on the used display. A shader how claims to be correct would show the indented art style in the new palette.
(Maybe should use optical lightness and saturation as the devs probably had no tool and could only adjust via eye)
*edit okay, the following may be a long strech but: I have seen this images:
https…byuu.net/images/video/color-emulation/7.png
https…byuu.net/images/video/color-emulation/8.png
And I imidently thought, hey, I know this (second) palette! Its the Pokemon spaceworld demo pal! Well kinda, but the idea sticked to me so I decompressed the colours from the dissasembly project ( (x*255)/31 ) of pokemon gold and spaceworld demo:
left: spaceworld; right: gold
Hmm, Okay lets come to my ‘crazy’ idea: The colours are from the spaceworld demo, before the GBC, so you think they took the only available colors they had, the SGB colours, but these are not SGB colours, not for pkmn, they had from green to yellow all a very pale palette, getting even brighter with yellow. And it’s odd that they match so perfectly with shaders trying to recreate the gbc colors. I think these colours on the left are gamefreaks unprocessed colors before they do the math/magic to convert them to a new palette. Like you see on the right with golds SGB colours. And here:
(can only have one image linked… sigh…) (will come later)
The only left overs I could find in gold that matches position inside the rom (left: spaceworld; right: gold) ( I stripped white and black, as they are the same as above) I think these colours are the result of another magic spell converting the spaceworld colours to GBC ready colours
This sounds like something torridgristle worked on awhile back, where he compared the same pokemon sprites on GBC and GBA (so you’ll also want a GBA color shader in there with it):
Thank you! Does torridgristle have a thread where he talks about this? But this would be a shader for a compromise between gbc and gba?
As for now, I search for a game where I/people know that there is an intended style in the palette, so I/we can work with that
atm I put together a ‘new’ gamma correction that should work with the most consoles
(its very subtile and need different tables per console)
Quick=(raw color + colorspace table > corrected gamma and slightly adjusted colorspace)
Here you can find an ‘interactive’ demo, because I have no idea how to program a shader (Credit: Pokefan531, JamesF, torridgristle)
These functions can handle color tables for color corrections / simulating of displays, but normaly should only use small values to counter color-space of the hardware (if you want color correction add a addtional conversion)
You can set the Gamma input and output in 0.1 steps, higer or lower, if you can’t see a differents in the picture above
I’m half understand what you’re saying, but I just wanted to say that example image is pretty nice!
Could you show an example of a gba game for reference? Something like a Castlevania game (something that is super pale and de/unsaturated on the gba).
Sorry for my unintelligible post; But thank you for the nice comment (:
Yes I can do that, but as for now I do it all by hand… so I will do it this evening, but it could take a while
It wasn’t so much your post was unintelligible, it was more that it was formatted poorly and the subject matter is slightly out of my understanding.
Mhm saturation is a bit more complicated to work with as I thought, there are some ways and alternatives to manipulate them so I will have a look into this, and come back if I have something to show
I haven’t read the new posts as of yet, but I got some great news. I got colormunki display and I was able to grab the screen dats for Original NDS. Here is the link for HCFR pics and few showcase:
that’s awesome news! I look forward to seeing what you come up with 
Glorious 30% sRGB coverage. 
I finished the NDS shaders a while after my last post. I would cover more speculation when I release it.
Right now, I’m doing GBA, and it’s really hard since it has no backlight for Colormunki Display. The screen has glaring and it has rainbow reflection when you flash a light on it with your phone or flashlight. I tried doing the method for Colormunki to do projected mode, and while it’s close, it’s still really challenging. I wouldn’t get the exact results because of glaring and rainbow, as well as being kinda hard to read the screen. I don’t think Colormunki Photo would work with glaring issues and it’s really expensive. GBA SP 001 would be too dim for any colorimeters to read correctly. Shooting light directly would help the results. Are there any better methods or suggestions to do this process more effectively?
