MiSTer FPGA Forum

as we all know, orginal psx missing Z-Buffer feature, which causing 3d graphics to be wobly.

i was wandering if its technicaly possible to add Z-Buffer to psx core ? it would make the core supperior to original hardware
cheers

I love the wobbliness, and all the other PSX gfx quirks. It gives its games unique look and character. I'd say I even prefer it in some cases to the latter PS2 look, which is kinda boring and sterile in many games.

So perhaps not exactly "superior", but as long as it's an option, by all means, go ahead.

You can add a Z-buffer, but the PS1 library was not programmed with a Z-buffer in mind. Chances are that the Z-buffer either wouldn't do anything at all with the existing game library, or it would create annoying glitches in most games.

Some emulators have what they call PGXP which tries to fix the wobbliness, with mixed results. When it works correctly, it's pretty cool.

duckstation doing a great job with z-buffer emu, lot of games i have tested looks very nice.

It's not really viable with the ressources we have, both memory requirements (you need to read back every pixel for z-buffer compare) and logic(FPGA is 90% full).

If I remember correctly the wobbliness is caused by the lack of perspective-correct texture mapping (it uses affine texture mapping). Developers used tricks to limit the effect and personally I don't mind it.

The core is pushing the limits already and I don't know how hard it would be to add perspective correct texture mapping in FPGA.

FPGAzumSpass wrote: ↑Tue Feb 22, 2022 6:03 am It's not really viable with the ressources we have, both memory requirements (you need to read back every pixel for z-buffer compare) and logic(FPGA is 90% full).

that what i was worried about but its always good to ask

FPGAzumSpass wrote: ↑Tue Feb 22, 2022 6:03 am It's not really viable with the ressources we have, both memory requirements (you need to read back every pixel for z-buffer compare) and logic(FPGA is 90% full).

Are you gonna keep the save state feature in once the core is completed or a you considering using the FPGA space for something else?
Save state is absolutely amazing and it got me to finish a few games way faster, but I wouldn't mind to see it go for some pretty cool extra fonctionalities.
Especially since you said a while back that it takes a big chunk of the space on the FPGA. Was it 30%?

Anyway thanks for making the PSX core and so many other possible on the Mister!

The savestates will stay. The core has all features implemented that are really required and will cost large ressources, so there is no important reason to remove them.