Home Page Forums MAME MAME HLSL: vertical scanlines for Game Gear

After a very long time, I finally got my hands on a real Sega Game Gear. It was quite a treat for me as I could play those old GG games as I remembered them with a crappy colour screen and the sound coming from the lower left of this screen.

I've enabled HLSL on my MAME installation, and I found out that something wasn't right: in MAME the HLSL scanlines are horizontal as most TVs handled them but on my real GG the scanlines are actually vertical!

So besides the colour bleeding, is there a way to render vertical scanlines with HLSL? I looked a bit at mame.ini and scanline_* options and it doesn't seem like there are any options related to scanline orientation.

You cannot change the direction of the scanlines, they depend on the rotation/orientation of the screen. Anyway, the Game Gear screen does not produce scanlines. What you see as scanlines might be the gaps between the RGB pixel-blocks of the LCD mask, but most likely you see only the pixels of a certain color, e.g. on a blue background only the blue pixel will be lighted.

Try this gba.ini with this slot-mask-aligned.png texture. I made this for Game Boy Advance but with some tweaks it should also work for Game Gear and other screens with a similar appearance.

It makes sense. Using scanlines on a dedicated display would be quite silly. I'll try and see how gba.ini fits compared to GG display. Thanks for your help

You could also use the "Scanlines.png" in the artwork folder and assign it as a effect-file in your .ini file



of course you need to rotate the Scanlines.png with any image-editor program prior using, elsewise you will end with the same problem of the "wrong" scanline alignment.

xinyingho, if you obtain a satisfactory result, could you share a screenshot of a Game Gear driver using HLSL and running a game that uses SMS compatibility mode? There are few GG games using that mode, or you can test with SMS games on a GG driver using the Master Gear (mgear) adapter, like done by the following example:

mame gamegear -cart mgear -cart2 roms/sms/altbeast.zip

Note: currently, the mgear subslot (cart2) requires a direct path to the ROM file. I sent a minor patch to etabeta sometime ago that adds software list support to the device, but while he doesn't find free time for MAME we still need to provide the path.

In SMS mode, the GG LCD display scales the image through subpixel rendering. The driver has a scaling algorithm implemented, but the result is somewhat off the mark. I think this is caused by the pixel-level rendering of the driver when HLSL is not used. I'm curious to see if HLSL will look more faithful to the real image produced by the GG LCD display. For reference, the following link points to a comparison image of how a SMS game looks on SMS and GG:

http://retrorgb.com/images/SMSonGG02.jpg
(from webpage http://retrorgb.com/smsongg.html)

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Enik

Enik: you can avoid individual devs being backed up by submitting a pull request through github - stuff submitted that way usually makes it in within a few hours if nothing's obviously wrong with it.

RB: Thanks for your help, but I just have mentioned the patch for information. It's a minor change of low priority that I prefer wait for his verification on it along with other software list stuff (all eta's ground) that I talked with him on that occasion.

Back on topic: as stated above, I'm curious to see how a game using SMS mode on a gamegear driver will look with HLSL.

Since MAME version 0.172, the mgear subslot (cart2) has software list support to load SMS games:

mame gamegear -cart mgear -cart2 altbeast

I was able to test HLSL with the emulated SMS scaling of the GG LCD, using a copy of gba.ini file, named gamegear.ini. The result looks closer to the image provided by RetroRGB:

http://retrorgb.com/images/SMSonGG02.jpg

Unfortunately, there is at least one issue with color bleeding that is not present in the image of the real GG output. Instead trying to explain the details here, I made a PNG to illustrate the issue, aiming to be self-explanatory. Link to the image:

http://tinypic.com/r/poa43/9

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Enik

I don't understand why Sega pick that screen. Pretty bad pick. The one on the left.

This issue should be fixed with bef7074.