Some minor graphic issues on pcsx rearmed

RetroArch General
#1

The issues are with the neon gpu on default settings

1.)Threads of fate has some weird polygon syndrome(play a new game using the girl)

2.)The battle transition in Final fantasy VIII is not rendered corretcly while the battle swirl in Final Fantasy VII is very inaccurate

3.)ON a battle in Final fantasy VII,every time a.a characyer or enemy attacks, b.The number indicating the damage or incured or the hp recovered is shown,

the dithering in the background disappears.This does not certainly happen on a psx console

4.)This one is not really an issue but is a request

Dithering is missing on scenes with pre-rendered backgrounds(I noticed it in Final fantasy IX on the prima vista crash site but is still found on other games) and on FMVs.On a real psx,there is dithering on the said scenes

#2

Mind taking a picture or something? I know Xebra dithers the hell out of everything, including pre-rendered backgrounds in FFIX, whereas no other emulator, including Mednafen, does. I decided to check if the real game played on my PS2 looked like Xebra, but it actually looked exactly like Mednafen instead, with no dithering on pre-rendered backgrounds. So unless only original PS1s had dithering…

#3

looks like i overreacted about the pre-rendered background thingie

From what i’ve read,xebra has too much dithering although im not sure

#4

Dithering on early 3D consoles is an interesting topic. It was done automatically by the graphics hardware and the exact characteristics–like where and how much–likely varied even among console revisions. In cases like that, emu authors usually either pick one console revision to target or they leave it off altogether since it will never be satisfactory to everyone.

For N64, leilei’s 3dfx shader makes some very convincing dithering that compares quite well with my console. I haven’t tried it with mednafen-psx, but it’s probably better than nothing, even though it’s targeting completely different hardware.

#5

I’ve read the PS1 GPU went through at least one revision, but AFAIK it was only minor differences in really technical stuff, nothing to do with dithering, and the first version was only in really early models, meaning the vast majority of PS1 consoles used the second revision.

I still stand by my belief, until proven otherwise, that Xebra inaccurately dithers certain things. From my testing, Mednafen is the more accurate of the two regarding dithering, on top of being just as accurate in terms of pixel-accuracy and geometry rendering.

#6

This forum thread suggests that no$psx is at least reasonably accurate about it, so you could probably compare with it.

From no$'s docs:

24bit RGB to 15bit RGB Dithering (enabled in Texpage attribute)
For dithering, VRAM is broken to 4x4 pixel blocks, depending on the location in that 4x4 pixel region, the corresponding dither offset is added to the 8bit R/G/B values, the result is saturated to +00h..+FFh, and then divided by 8, resulting in the final 5bit R/G/B values.
  -4  +0  -3  +1   ;\dither offsets for first two scanlines
  +2  -2  +3  -1   ;/
  -3  +1  -4  +0   ;\dither offsets for next two scanlines
  +3  -1  +2  -2   ;/(same as above, but shifted two pixels horizontally)
POLYGONs (triangles/quads) are dithered ONLY if they do use gouraud shading or texture blending.
LINEs are dithered (no matter if they are mono or do use gouraud shading).
RECTs are NOT dithered (no matter if they do use texture blending).

EDIT: I just checked and mednafen-psx looks pretty close to no$ (at least in the limited comparisons I made), so I would say you’re probably right that Xebra is probably overdoing it.