Can Super Game Boy borders be hacked?

[nensondubois]

That's what 13h is. Ok.

[ReyVGM]

As for the other 2 images, are you aware that there's the potential for the Super Gameboy to display actual image data on the screen besides the border? It may be the same format, but it would be referenced and displayed in a very different way.

Hence, the information for border tiles will be identical to information for foreground sprite tiles. It probably replaces a logo on the screen at some point that has a similar look to it. You'd be hard-pressed to notice this with the SGB coloring going on, but it is quite possible.

Yep, I am aware. Not only that, on one of my previous messages I said that Monster Rancher Battle Card had a second border because I was clearly seeing some kind of "border-like" image inside the ROM. But when you said that there wasn't any other border, I went back to the game and remembered there was a mural in the game that I didn't pay much attention. When I went and saw the mural, indeed, I saw that the alleged second border was really in the game.

But for NHL 2000 and Pocket Love 2 I couldn't find such images in the game.
The only place where NHL 2000 would have such image is in the ending, and it didn't.
Unless, if playing in GBC mode you would get graphics that couldn't be done on the SGB. But then again, they wouldn't be those 4bpp snes style images like the borders because the GBC couldn't display those.

As for Pocket Love 2, I beat the game on every possible way and I didn't see such image either. The only place where there's a similar logo is in the title screen, but I compared each pixel to the one on the title screen and they don't match. It does match the border one though.

So I guess it's an unused border or something?
OR it's something that only works on an actual Super Game Boy (like the enhanced music) and none of the emulators emulate it correctly.


As for the rest of the codes, thanks a lot ugetab. You have been the most helpful!

[ugetab]

1. GBC mode doesn't support SGB enhancements
2. Images aren't required to replace something from the GB version of the screen. They can be put anywhere, any time, if coded to do so in the game.
3. Watching for OBJ_TRN calls in BGBs debugger could allow me to find out exactly what's being displayed, and likely where on screen as well.

I decided to work out some codes to make Pocket Love boot a little better in BGB:
Enable Boot:
C93-19F
3F9-35F
002-22F
007-BDC

Menu Options:
001-3FB-081
009-64B-081
006-9CC

Text Mover:
01010FCF

I didn't see anything that pointed to it using the thing on the title screen, but it is pretty hacked up just to make it that far.

[nensondubois]

That's the same SGB border that's used in Mario's Picross.

[ReyVGM]

By Pocket Love you mean Pocket Love 2, right?

The game loads fine on VBA. Why do I get an invalid op code when I run it in BGB? It does run if you select "prefer accuracy" over compatibility, but it only runs in GB mode.

Also, I don't quite get what you wanted to do with those codes other than make it run on BGB.
Are you trying to find out if there really is another border or is your final decision that there isn't one?

I'm certain that's another border, unless it's being applied to the title screen like you said. But I think that could happen only if played through a real Super Game Boy. (I may be talking out of my ass there)
I beat the game, but not under the best conditions. It's possible that you might get the extra border if you beat the game with a good ending.
Pokemon Card Battle did that, the border changed from blue to gold once you beat the game.

Other reasons why I'm positive that's a border is because, on the surface it looks like something that could go over the title screen, but if you notice, the girl's head doesn't match the girls that appear on the title screen each time you reset the game. There's some Japanese text with a small heart that looks a lot like the one shown on the title screen, but if you compare the characters, it doesn't match either.
The pixels match the ones in the default border, but it doesn't match the one on the title screen.
If you see the image below, that vertical line on the left of the girl is probably the frame of the GB screen.

Here's a better constructed image:




Nensondubois: If you are talking about the Tetris 2 border, It's not the same , it might look the same but it's not. If you compare them you'll see.

[nensondubois]

It's not, yeah. They may have used it to fill space.

[ugetab]

I see kind of how the border's supposed to look now. It's definitely only using a partial difference based on that. It'll probably be something weird like a palette switch. I haven't completely figured out how borders are changed in all ways yet, but I can still try different things. Pocket Love 2 requires a lot more time because it won't boot in the SGB debugging emulator I use, and use SGB mode at the same time.

Also, I was making it boot into BGB because by reading the SGB packets, I can tell if it's transferring Object data which would appear on the screen. I could only see that in action if it's running in SGB mode.

As a side note, I'm working on a conversion of the SGB color editor system into VB. I've got the brightness stuff down, in addition to the base colors. Now I need an interface and a code encoder/decoder. I think that would finish it up nicely.

[ReyVGM]

I see, yeah I forgot there that you have to use BGB for the SGB packets option.

Well, I hope everything goes according to plan with that sneaky border

[ReyVGM]

I'm just going to leave some of my notes for record purposes:

1) The game "Same Game" has two borders. One when you load the game and another when you start the game (Green background, a samurai and a cowgirl).

Looking at the roms with a title viewer, I noticed that same green border is inside the games Bomberman Collection and Momotaro Collection 1 (all three are made by Hudson).
As far as I know there's no way to get that border by playing the games. ugetab found codes to unlock/show them in the game.

At first I thought that maybe Hudson had reused the "Same Game" code on Bomberman and Momotaro and didn't bother to delete that border from the code.
But then I noticed the dates, Bomberman and Momotaro both came out in 1996 and Same Game in 1997.
So now I wonder, what was a totally unrelated border from a future game doing hidden in two totally unrelated games? Maybe Same Game was supposed to have come out before Bomberman and Momotaro Collection?


2) The Daffy Duck Marvin Missions border.
I played the game all the way through the end and only saw one border. But peeking inside the rom with a title viewer I saw another border. ugetab found a code to unlock it.
However, I don't think the border is hidden.
The border looks exactly like the last room before the ending (large empty room with a huge telescope), the problem is that the game is really really really hard and I had to use cheats to get to the end. But so it happens that when I did get to that room, the game bugged out and the character glitched through the floor and I automatically got the ending.
My guess is that the border is supposed to appear in that room, but the cheats and the glitch prevented the game from showing it. I don't think I'll play that game without cheats to confirm that.

3) Pocket Love 2.
There is a second border, I didn't see it in the game and ugetab has been unable to find a code to unlock it due to problems with emulation on BGB.

4) Game Boy Wars 2.
There is a second border hidden inside the rom. The border looks exactly like the one used for Gameboy Wars Turbo. Both games are very alike, so my guess is Hudson reused the code from the 1997 GBWTurbo with the 1998 GBW2 and didn't bother to remove the border. The border also looks incomplete, so my guess is that it really doesn't appear in the actual gameplay.

5) NHL 2000.
It looks like there's a second border. ugetab was unable to get a code for it.
While looking at many roms with a title viewer, I've noticed that most games with multiple borders usually have their border titles grouped together one right after the other. On NHL 2000 it's the same case. That's why I assume it's a second border.
It could very well be SGB style titles that appear in the actual game and not as a border (it happened with Monster Rancher Battle Card), but the problem is I never saw those titles in the actual game (while I did see it in Monster Rancher).

6) Tetris 2 has an extra 6th border that I didn't see in the game. While playing the game, if you pause and press the A button, you can cycle through 5 borders. With a title viewer I saw a 6th border that looked like the Super Game Boy's default border (it looks like it, but it's different). I have no idea where that border is used in Tetris 2 or if it's even used at all.
The game actually loads without any border on an emu. On a real Super Game Boy you would see the default SGB border. I don't know why they would include yet another border that looks like the default SGB one. Maybe when you load the game on the real thing you actually get that 6th border that looks like the default one, but because the differences are so small, one never noticed?
But then again, why doesn't that border load on an emulator too?


7) Bomberman Quest has a second border if you link two games together. However, that's only possible with the SGB2 since that's the one that has a linking option. Weird Hudson created a border just for the very small number of people that would have linked the game on a SGB2.

8) I saw a possible 3rd border for Space Invaders. However, the game has a full screen mode if you play it on a SGB which is not possible to recreate on an emulator because you need an actual SNES unit. So I guess that 3rd border is just SNES type graphics when you play in that mode.

[ugetab]

I now seriously believe that it's either an implementation of CHR_TRN that uses the image, or that it was a prospective feature.

Bank 12 is loaded only a few places in code. I checked them and they don't seem to have anything useful. A CHR_TRN with a value of 01 is needed to transfer the extra tiles used to construct the image. This line isn't present in the code. Once rebuilt, the image didn't have any compatible palettes to go with it.

So, here's the best you'll likely get: An IPS patch to get as close as I got to reproducing the border.

[ReyVGM]

I see, I guess that it is indeed something that never made it into the final game or else you would have gotten it already.