Force GBC/SGB mode in GB games?

[ShadowOne333]

Hello there.

I've been playing a lot of GB lately, and I notice that non GBC games usually boot in black and white.
I was wondering if there is a way to make GB which have special palettes when played in GBC to be loaded up with mGBA.
Same thing goes for games with special palettes when booted through SGB, like Metroid II.

I believe this is related to the Gameboy Color BIOS having some palettes stored in its data usually linked to the ROM's specific header, though I'm not sure if this is actually the case.

A more in-depth information about the Gameboy games being colorized in GBC mode is found here:
https://tcrf.net/Notes:Game_Boy_Color_Bootstrap_ROM

So with that said, the question is, can we boot games like Kirby's Dream Land in color in any way with the current mGBA builds? Or is this still in planning / not implemented into it yet?

[endrift]

It's still in planning. You can force GBC booting but it seems to be a bit broken right now.

[endrift]

GBC booting now works and using a GBC BIOS to set up the colors works. I do need to import the color table regardless.

[ShadowOne333]

Thanks for the quick reply!
What path do I need to put the GBC bios in and with what name?

[endrift]

You can put it in the same dir as the config files with the name cgb_bios.bin IIRC (it may be gbc), or you can configure it manually in Settings > BIOS

[ShadowOne333]

Ah great!
I think it's gbc_bios.bin, 2.5kb or so from the one I found.

So for other ports of mGBA in consoles, the bios should go alongside the .cfg file?

[endrift]

Yep!

[ShadowOne333]

Great! Thank you

[Dante164]

Hello there.

I've been playing a lot of GB lately, and I notice that non GBC games usually boot in black and white.
I was wondering if there is a way to make GB which have special palettes when played in GBC to be loaded up with mGBA.
Same thing goes for games with special palettes when booted through SGB, like Metroid II.

I believe this is related to the Gameboy Color BIOS having some palettes stored in its data usually linked to the ROM's specific header, though I'm not sure if this is actually the case.

A more in-depth information about the Gameboy games being colorized in GBC mode is found here:
https://tcrf.net/Notes:Game_Boy_Color_Bootstrap_ROM

So with that said, the question is, can we boot games like Kirby's Dream Land in color in any way with the current mGBA builds? Or is this still in planning / not implemented into it yet?

Hello ShadowOne333 I have the same problem as you with the same video game. I followed your steps download the BIOS called gbc_bios.bin. Weighs 2.25kb. After activating the BIOS you can see the correct colors in the video game of Kirby. The only problem is that the kirby sprite looks red and white when it should look pink. Any advice to solve this problem? by the way, sorry for my bad english thanks in advance (Y)  

[lordelan]

Hi folks. I just registered here for this topic as I'm very interested in this.

I grabbed the recent dev build of mGBA (Windows) and tried a bit around.
Also I grabbed myself the BIOS files for GB, GBC and SGB.

My first attempt was Pokémon Red Edition without any BIOS files.
To my suprise it already has it's correct SGB border as well as the SGB color palette:



I continued with a game that has both, called Dragon Quest/Warrior Monsters:

• SGB support (at least it has a border as you can see here)
  
• GBC palette (as it was a black cartridge with GBC support)
  

As you can see it has all the official GBC colors. Of course it does, it's an official GBC game at least. Unfortunately it doesn't have it's SGB border no matter what I try.

In my 3rd attempt I went for Turtles III which is an old and original GB game with no GBC palette and no SGB borders:



It's black/grey/white by default but can be adjusted in the settings:



Sorry for providing a german screenshot. The first row is for the background, the second and third row for the sprites. That's pretty cool but I would prefer it to be on GBC default instead of black/grey/white. You know, when you put in a GB game into the GBC, turn it on without pressing any button it get's a blue/red color palette as far as I remember.

@Dante164: Additionally I tried my luck with the same rom you used and I don't have those glitches in Kirby's sprite. Dunno whether this might have been fixed as my dev build is from today.



So a few questions @endrift:

1. Can you apply a Super Gameboy border (at least as an option) to all games including those without SGB support, showing the simple SGB general border as you can see it here?
   
2. For games supporting both, GBC and SGB (like Dragon Quest Monsters), would it be possible to show it's specific SGB border?
   
   
3. To be honest I don't know whether games that support both have the same color palette on both (GBC and SGB) or which is superior, but if the GBC is superior could you enable it while having the SGB border around it at the same time?
   
4. Last but most important question, not only to me but ShadowOne333 as well: Can this be done to the Libretro core of mGBA using RetroArch as well?
   If so, how and when?
   

Thanks for all your great work man!