Hi, some years ago, a friend and me were working in a
NeoGeo emulator (it never saw the light, as others did
better work), but in our project, we implemented a
technique I haven't seen yet in any emulator:
To increase the visual quality of the image, we
duplicated the stantard screen resolution of the NeoGeo,
and at the bare end of the rendering pipeline, we also
duplicated the GFX, like zooming by 2.
In a normal game, you wouldn't see any difference
between a normal resolution and a x2 resolution... but in
a particular game, like Art Of Fighting, where all the
background was zooming in and out, the effect was very
impressive, because you were actually seeing 1 pixel
dots instead of 2 pixels dots.
I am not sure if this is possible with the architecture of
the PSX GPU... theorically, it would be a matter of x2
the size of the rendering buffer, and also x2 the size of
all 2D gfx rendered... polygon coords would have to be
x2 too, giving a much smoother 3D renderings.