Prepare for using gbc mode with gb games, fix register inaccuracy

[meepingsnesroms]

(the force gbc was disabled since it has unresolved issues)

[ghost]

Looks good to me, nice work! Really hope this gets merged soon. And I like the idea of finally having the choice of choosing between GB, GBC and GBA and not just Auto, GB and GBA.

[sergiobenrocha2]

I'm forcing GB, the GB bootloader appears, and then I still can use GB colorization auto or internal, which makes senses only with GBC or GBA [& no bootloader].

Forcing GBC & using bootloader, it conflicts with GB Colorization and Internal Palette, dunno if it's by purpose (since you can change the palette in the bootloader now). Shouldn't GB Colorization be disabled when using bootloader?

Forcing GBC and Use official bootloader = OFF, gives you a buggy palette (picture below), and you are unable to use any GB Colorization setting.

[sergiobenrocha2]

Shouldn't Emulated hardware have an default 'auto' option? If .gb rom, loads as GB, if .gbc rom loads as GBC

[meepingsnesroms]

Forcing gbc and loading a gb rom without bootloader is not supported and never will be, the way I implemented the bootloader it actually boots the system, since the gb and gbc are not the same the gbc bootloader puts the gbc in gb emulation mode which just booting wont do, thus the corrupt palette.

Set to gb mode for gb games or install the bootloader. You can also try the sameboy bootloader if you want an open source one.

[sergiobenrocha2]

Wait, are you expecting people using real bios now? So by default we'll have a 'broken' core?

[meepingsnesroms]

No,just set the switch to gb if you are playing a gb game, and if your not using a bootloader turn the Use official bootloader to off.

I made sure the best that I could that everything still worked the same when not using a bootloader.

[ghost]

@meepingsnesroms I don't think it's right to require the user to select the right core option for every game. For example, say your system/bios folder is the default ("content dir") and you previously played a GBC game with "emulated hardware" set to GBC. If you now want to play a GB game, and your GB folder doesn't have the GBC bios in it, then you get corrupted graphics and no bios screen at all.

[meepingsnesroms]

I can put back the auto option too then.

[meepingsnesroms]

Put the auto option is back and fixed some bugs.

[sergiobenrocha2]

Ok, it's working with Auto now, but if you chose 'Emulated hardware' GBC it still get the buggy palette (with no bios in the system).

When people force GBC, they are expecting a fully Game Boy Color in their hands, which plays nicely both gbc and gb roms.

Please test all user cases, otherwise we'll get a ton of bug report here, reddit, forum...

[ghost]

Loaded save states now have an incorrect palette:

http://imgur.com/a/IKCVc

This does not happen in the current master branch.

And one time I also got a buffer overflow on startup:

https://www.hastebin.com/ukegilabug.pas

But could not reproduce it a second time. I'm not sure if this is a new bug or not.

[sergiobenrocha2]

GB Colorization = internal Internal Palette = GBC - Blue Emulated hardware = GB Use official bootloader = ON, but no bios in my directory

Does this exist in real world?

---

Found another case:

GB Colorization = custom (with palettes/default.pal in System/BIOS) Internal Palette = GBC - Blue Emulated hardware = GBC Use official bootloader = ON, but no bios in my directory

It'll load the gbc game fine, then change GB Colorization to 'internal' or OFF while running, you'll get this:

You'll get it if you change initially from OFF to 'custom' too.

[ghost]

No,just set the switch to gb if you are playing a gb game, and if your not using a bootloader turn the Use official bootloader to off.

How hard will it be to pragmatically detect if the bios files are present or not, and then to optionally use the bioses if the files are present? How is this pull req done?

[meepingsnesroms]

I thought it was finished at the time but with the issues it's not even close.

[meepingsnesroms]

All mentioned bugs other than force gbc without a bootloader and palette swap in game have been fixed.

[meepingsnesroms]

The gb mode with blue palette does exist,it is a gb game that can use extended features if available. Heres a video of it on gb. https://www.youtube.com/watch?v=pWEemiNnhb4

As for custom palettes I did not mess with the palettes from file, they might be remapping the gbc colors too.

[sergiobenrocha2]

Game Boy is monochromatic dude

There's no sense Gold using Blue palette

[sergiobenrocha2]

Another user case:

Emulated hardware = GBA Use official bootloader = ON (with bios in the directory)

Load a gb game, you'll get this:

Edit: Oh, actually you fixed that in last commit

[meepingsnesroms]

You can turn the blue palette off, but this game supports monochrome mode and if you have palettes enabled and force gb this will happen, its normal.(This is not a bug, it is your theme setting, change it to "Grayscale")

I fixed the gb games in gba mode in my last commit.

[sergiobenrocha2]

I think you are not looking the big picture here. When you force either GB or GBC, people should expect gambatte working as a real GB or GBC as whole, i.e. it'll boot the proper bootloader AND will have the proper palette support.

This is a fix for palettes when forcing GB:

--- libretro.cpp    2017-02-13 17:45:10.332828759 -0200
+++ libretro.cpp_new    2017-02-13 17:44:08.355847000 -0200
@@ -555,6 +555,13 @@ static void check_variables(void)
    if (gb.isCgb())
       return;

+   struct retro_variable var2 = {0};
+   var2.key = "gambatte_gb_hwmode";
+
+   // there's no colorization in real GB, this avoids having a GBC game with GB palettes too
+   if (!environ_cb(RETRO_ENVIRONMENT_GET_VARIABLE, &var2) || !var2.value || strcmp(var2.value, "GB") == 0)
+      return;
+
    // else it is a GB-mono game -> set a color palette
    //bool gb_colorization_old = gb_colorization_enable;

Edit: ugh, this is not the best way to do this, user can change 'Emulated hardware' from GB to GBC while running the game, it'll get the weird palettes

[meepingsnesroms]

I could make it check if the wanted systems bootloader is present and if not ignore the "Force System" option and always use auto.

Also then I would separate GBA mode into its own switch.(Use GBA GBC mode:no|yes)

Is that what you want?

As for running like a real gameboy, it is, that is how it would boot if you where able to remove the bootloader from the cpu.

[sergiobenrocha2]

I could make it check if the wanted systems bootloader is present and if not ignore the "Force System" option and always use auto.

No.

Also then I would separate GBA mode into its own switch.(Use GBA GBC mode:no|yes)

Also no, it'll get more complicate than which already is.

That gb palette in gbc games when forcing GB was an issue way before you messing with the code actually, sorry for the complains.

[sergiobenrocha2]

The only remain issues by your side is this I think:

GB Colorization = any option Internal Palette = any Emulated hardware = GBC Use official bootloader = ON (with bios in the directory)

After loading the game, change the 'GB Colorization' to any option, even with you turning it back you'll get this:

Changing 'Emulated hardware' while running will get this too, even turning it back to GBC

---

GB Colorization = any option Internal Palette = any Emulated hardware = GBC Use official bootloader = ON, but no bios in my directory

I didn't get yet what's the point in adding a GBC force setting, when it's broken for gb games.

This should be working exactly like GBA mode, before this PR

[meepingsnesroms]

Ok I fixed that, it was still treating the palettes as gbc even when the bootloader had switched to gb mode.

[sergiobenrocha2]

Nice, you fixed the first issue in the last comment, not the second. You really want to push LLE on us eh?

[meepingsnesroms]

No I am not trying to force it, I fixed and submitted the patch before you edited the post so I did not even see it, I will fix it when I get home though.

[sergiobenrocha2]

Somehow, now you need to restart the game to get the changed value in 'Color Correction' updated when forcing GBC or GBA. It's working properly with Auto or GB. It was working properly forcing GBA before your first PR

[meepingsnesroms]

Does it work with GBC games in auto?

I intend to fix it, but I see no reason to turn that off because than the whole screen is just lightly tinted black.

EDIT:This is wrong,tinted black only happens on android on mac it just changes the hue, this is a major bug, it also existed before my changes.

[sergiobenrocha2]

Does it work with GBC games in auto?

Yes

[meepingsnesroms]

Theres a bug in retroarch or this core somewhere, on android turning off color correction turns the screen black.(This is using a version before I made any changes) On mac it just changes the hue.

[sergiobenrocha2]

Yeah, I notice that too.

Color correction is working properly now, but gb games have that weird green palette while forcing gbc

• using the bootloader

[meepingsnesroms]

The palette issues should be fixed, are there any others?

[sergiobenrocha2]

Yes, seems everything is working fine now