Output resolution

[Ashurek85]

Hi. I've been working on a homebrew project for a while now, and I'm not sure what output resolution I should use.

In the version of Gngeo included in the toolkit, the effective resolution is 304x224. I’ve tested the ROM in the latest version of MAME and found that the effective resolution appears to be 320x224. In MAME, there’s a video mode that lets you set it to match GNGEO, with the black columns.

I’d noticed in GNGEO two 8-pixel black columns on the left and right that seem to be overscan safe zones for CRT monitors.

Will the video output with real NeoGeo hardware be 320x224 or 304x224?

Currently, the black bars in MAME show “garbage.” Should I avoid this or just leave it as is?

Thanks

[sasja-san]

Sorry for being late with the answer.

The hardware outputs 320x224. You may not have noticed, this particular thing, but 320-304 = 16. If you're making a game with scrolling you don't want to over fill the VRAM with sprites. So you stop filling VRAM at the screen edges. Because this might cause some stripes of sprites to be slightly off, and due to CRTs being over-stretced in their tubes, the general advice was to not use the outermost pixels.

You should take a look at the fix layer doc on the ngdev wiki. One cheap trick you can do is just put black in the borders and that won't make your borders wobble as you scroll through the stage. In the image there, because each fix slot is 8x8 pixels, the effective "inner" resolution is 304x192.