Gameboy core

[Mills]

Hi, I was going to post this on github, but I think it is good to post here.

I tested a lot of games and demos, and the core is replicating everything like a real game boy , even sprite flickering (and some dma transfer flicker I saw in a demo I made).

But I noticed bugs in some demos and games that use scanline interrupts, it looks like it is not fast enough or something.

For example prehistorik man uses scanline interrupts to simulate parallax and some cool effects. This game runs with a lot of gfx missing in menu, and starting a new game shows just a black screen.

Also tested demos like GEJMBOJ, and the scanline effects are also missing.

A lot of game boy color games and demos use scanline interrupts to draw "highcolour" images (rayman, cannon fodder), or to change palette every scanline... and all of this is also showing gfx errors.

Thanks!

[brNX]

What would cause the Gameboy core to not provide audio over HDMI? Right now all my cores are providing audio over HDMI except the Gameboy core. If I plug headphones into the line out on the IO board it does provide audio just fine. For some reason it does not want to provide audio over HDMI.

Now if I hook it up to a different HDMI display the audio works fine. So it is 100% an issue with the particular display I am using. I am just curious what the difference would be.

~

Hi, I was going to post this on github, but I think it is good to post here.

I tested a lot of games and demos, and the core is replicating everything like a real game boy , even sprite flickering (and some dma transfer flicker I saw in a demo I made).

But I noticed bugs in some demos and games that use scanline interrupts, it looks like it is not fast enough or something.

For example prehistorik man uses scanline interrupts to simulate parallax and some cool effects. This game runs with a lot of gfx missing in menu, and starting a new game shows just a black screen.

Also tested demos like GEJMBOJ, and the scanline effects are also missing.

A lot of game boy color games and demos use scanline interrupts to draw "highcolour" images (rayman, cannon fodder), or to change palette every scanline... and all of this is also showing gfx errors.

Thanks!

Hi
sorry for the radio silence for a while, I've been very busy with life and will continue to be for some time unfortunately , sorry again.
@hernan43 I have the same issues with my TV over hdmi, my guess is that the sound output is missing a filter (LPF/HPF) so that the sound is in HDMI spec , some TVs don't care other don't like it at all.

@Mills yeah it's in my issues list on github, there are other things amiss with the PPU implementation, that one needs to be rewritten probably , I started to compare it in simulation with Sameboy but never got the time to finish it , different codepaths should also be added as the GBC PPU acts differently in a lot of places than the GB one (and of course Furrtek's recent work could be added/used).

[crocky]

brNX, thanks for the wonderful Gameboy core, with the LCD filters, its amazing!

I found that on R-Type II with the laser shot, the lasers dont show up on the front of the aircraft but on behind and yet the enemies get hit and die on front. I tried with filters off etc, still the same. Just letting you know in case this was not a known issue.

[12characters]

I am curious about the format of the palettes (.gbp). A hex dump of DMG.gbp gives:

Code: Select all

82 82 14 51 73 56 30 5a 5f 1a 3b 49 00 00 00 00

I recognise the first 12 bytes as the 4 colours of the palette, but what is the purpose of the 4 zero bytes at the end?

[12characters]

I am curious about the format of the palettes (.gbp). A hex dump of DMG.gbp gives:

Code: Select all

82 82 14 51 73 56 30 5a 5f 1a 3b 49 00 00 00 00

I recognise the first 12 bytes as the 4 colours of the palette, but what is the purpose of the 4 zero bytes at the end?

I found the answer in gbpalette.c:

Code: Select all

// GBP file format is simple. There are 4 palette colors using 8 bit
// rgb, starting from lightest ending in darkest for a total of 12 bytes.
// The last several bytes are 0, reserved for future use.

In case it is of use for anyone, I have converted some extra palettes to the format:

• The default palette used by the bgb emulator (taken from here)
• The default palettes used by gnuboy version 0.8 and 1.0, respectively (taken from the gnuboy source code)
• Super Game Boy's 32 preset palettes (taken from the source code of the libretro port of gambatte)

The GBP files can be found in the attached ZIP archive.

[trashuncle]

Megaman Extreme doesn't work properly. I believe this has already been reported. Any progress on this (or at least a reason as to why this rom behaves this way?)

[peepsalot]

I've found that the GBC game "Project S-11" has glitched graphics around the title screen and in some of in-game sprites. Not sure if this is a issue with the core itself, or could it be a bug due to the "sameboy" bios?

[Piacenti]

I've found that the GBC game "Project S-11" has glitched graphics around the title screen and in some of in-game sprites. Not sure if this is a issue with the core itself, or could it be a bug due to the "sameboy" bios?

I get these glitches on Aladdin and Aliens also, not sure what the problem is.

[peepsalot]

After reading back in this thread a little bit, I think its probably just more examples of the scanline interrupt issues that Mills already brought up at the top of this page.

[system72]

forgive me if this has already been covered, but is there a way to load specific filters based on gameboy and gameboy color?
the lcd_effect_br filters seem more appropriate for original gameboy roms, while the standard lcd_effect filters seem better suited to the gbc.. it would be nice to not have to manually select each time

[trashuncle]

15 Khz support incoming?!?! WOOOT!

[ElDoctor]

15 Khz support incoming?!?! WOOOT!

Already commited days ago.
Current OSD size is the only issue (not a big deal, you can still scroll and read), other than that it is really impressive.
And don' forget to enable Stabilize video (buffer), or screen transitions might not be your friend if you are epileptic.

Great job from paulb-nl.

[Sigismond0]

15 Khz support incoming?!?! WOOOT!

Already commited days ago.
Current OSD size is the only issue (not a big deal, you can still scroll and read), other than that it is really impressive.
And don' forget to enable Stabilize video (buffer), or screen transitions might not be your friend if you are epileptic.

Great job from paulb-nl.

Am I missing something, or is there not a new release since the commit? Is this a "compile it yourself" situation?

[magbombz]

And don' forget to enable Stabilize video (buffer), or screen transitions might not be your friend if you are epileptic.

I apologize for asking something that's probably answered in a thousand places, but I keep looking for what the stabilize option is, and I can't seem to find it. Is this a .ini setting, or is it something within the OSD for the gameboy core?

I'm currently trying to get my JVC CRT to display when starting the core, but running into trouble. Trying out various [gameboy] settings for video_mode and such in my mister.ini.

[trashuncle]

Its part of the next build, which hasn't been compiled for official release yet.

[ElDoctor]

15 Khz support incoming?!?! WOOOT!

Already commited days ago.
Current OSD size is the only issue (not a big deal, you can still scroll and read), other than that it is really impressive.
And don' forget to enable Stabilize video (buffer), or screen transitions might not be your friend if you are epileptic.

Great job from paulb-nl.

Am I missing something, or is there not a new release since the commit? Is this a "compile it yourself" situation?

Do you understand what open source means and how github works???

[Sigismond0]

Yes, I understand. Which is why I was asking for confirmation as to whether there was a release I missed. The readme on github already updated to remove the framebuffer details and has comments about the new settings, and we've got someone in the thread here talking about using it. It's not unreasonable to ask, as there's clearly at least one other person who's confused.

[djmartins]

Do you understand what open source means and how github works???

Hunh?
Isn't this an FPGA project?
What is this open sauce glithub thingie you talk of?

[ElDoctor]

Do you understand what open source means and how github works???

Hunh?
Isn't this an FPGA project?
What is this open sauce glithub thingie you talk of?

"open sauce glithub" ...
What about selling your DE10 nano and use the cash for a dictionary?

[RETR0Gamer]

Do you understand what open source means and how github works???

Hunh?
Isn't this an FPGA project?
What is this open sauce glithub thingie you talk of?

"open sauce glithub" ...
What about selling your DE10 nano and use the cash for a dictionary?

Guy was obviously joking with you...

[ElDoctor]

Hunh?
Isn't this an FPGA project?
What is this open sauce glithub thingie you talk of?

"open sauce glithub" ...
What about selling your DE10 nano and use the cash for a dictionary?

Guy was obviously joking with you...

Tough to tell what is a joke or not on this thread...

[djmartins]

Guy was obviously joking with you...

[djmartins]

What about selling your DE10 nano and use the cash for a dictionary?

https://www.merriam-webster.com/diction ... h-dict-box

“github”

The word you've entered isn't in the dictionary. Click on a spelling suggestion below or try again using the search bar above.

LMFAO!

[trashuncle]

wondering when we will get the update on this core, really eager to try it out on my PVM now that 15Khz mode has been added.

[SegaSnatcher]

Can someone clarify something with the new Gameboy release?

Was this core defaulting to one of the buffered modes before the 3/31/20 release? Because I didn't have any sync issues using V_Sync = 2 in previous builds, but now I have to turn on the stability feature or else I lose sync. So what changed?