Force GBC/SGB mode in GB games?

[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!