Feature Request: Deposterization filter for xBRZ

[DonelBueno]

xBRZ scaling leaves the textures with posterization issues. The same issue happened on PPSSPP, but they sorted it out with a deposterization step. The issue and the solution are both described here:

http://blog.metaclassofnil.com/?p=306

Example of the issue in GLideN64:

Pay attention to the sky texture. The first one is xBRZ filtered, the second one is HQ4x.

It's way more evident in some games, like in Ocarina of Time. The ground texture in that game gets really distracting.

[ADormant]

@gonetz
Deposterize Tinob/Ishiiruka@d2fb925

[ADormant]

@gonetz Deposterize shader libretro/common-shaders@cc81b1f

[gonetz]

I've added the deposterization step from Ishiiruka's code:
78d7c99
I don't see much difference though.

I can't share the binary via googledrive because it says that the file is infected. I tested the file via virustotal - ClamAV reports about Win.Adware.Browsefox-12346, others 54 antiviruses reports that the file is clean. If you need the binary, you may write me an email, I'll send the file to you.

[theboy181]

Zip with password protection and share the password in the info file.

[gonetz]

Good idea. The binary:
https://drive.google.com/file/d/0B0YqMPjGo3B2VU0tVkdST0ViUWc/view?usp=sharing

pass: deposterization

[ADormant]

@gonetz Changes are supposed to be subtle http://libretro.com/forums/showthread.php?t=4908

[gonetz]

If you see the positive difference in quality, I'll add that code to master.

[DonelBueno]

I'll check it out soon and then post the results here. Thanks for the attention.

[DonelBueno]

Test Results:

No Texture Scaling:

HQ 4x Texture Scaling:

6xBRZ Texture Scaling:

6xBRZ + Deposterization texture Scaling:

As you can see, there is basically no change to the posterization on the ground textures.

[ADormant]

Colors are better with deposterize enabled, Buttons around Navi button become lighter yellow instead of brownish and green circle seems to have better transparency.

[DonelBueno]

@ADormant You must be comparing the wrong images. Compare 6xBRZ Texture Scaling to 6xBRZ + Deposterization texture Scaling (the last two images).

They are basically the same, aside from some very minor differences on the ground textures, but these differences aren't for the better, they are just different.

[ADormant]

Still wouldn't hurt to add it looks somewhat different after all.

[gonetz]

It hurts performance, since the deposterization step is not free. I can make it optional though.

Regarding the result: it is probably a bad idea to use maximal BRZ level. Try 3x or 4x BRZ, may be difference will be more noticeable.

[gonetz]

I suggest to close this issue since deposterization step does not help to solve problems with xBRZ and N64 textures.

[ADormant]

@gonetz Deposterize is good for games with dithering https://github.com/tapcio/PeteOpenGL2Tweak/releases

[gonetz]

Most of N64 textures use 16bit color, however deposterization has no visible effect. N64 texture size may negate the effect, because N64 texture memory is just 4kb.

[ADormant]

Hmm PS1 texture cache is only 2kb.

[gonetz]

I have fixed an issue in GLideNHQ code and now deposterization effect is clearly visible

Test binary:

https://drive.google.com/file/d/0B0YqMPjGo3B2LTVtcHAzX3ZDUjg/view?usp=sharing

[oddMLan]

Earthworm Jim 64 - Normal

Earthworm Jim 64 - X2 + Deposterization

Earthworm Jim 64 - xBR 3x Normal

Earthworm Jim 64 - xBR 3x + Deposterization

Zelda OOT - Normal

Zelda OOT - X2 + Deposterization

Zelda OOT - xBR x4 Normal

Zelda OOT - xBR x4 + Deposterization

I wonder how deposterization helps KI Gold. I'll test later.

[gonetz]

So, deposterization is useful after all. I'll add it to master. I think, it should be optional though.

[oddMLan]

I agree; it should be optional. Just like in PPSSPP.

[DonelBueno]

I helps Earthworm Jim a lot, but it doesn't seem to help OOT.

I also think it's a good idea to include it into master.

[gonetz]

Done

[gonetz]

Has anybody my dev branch with Deposterization feature in your local git repository?
Deposterization is completely broken in master. It seems that I broke on when merged code to master.

[fzurita]

What's breaking it? I'm not seeing any issues right now with it enabled in Android. Amy specific examples?

[gonetz]

I have issues in every game, e.g.:
#1301

[gonetz]

I see the problem. It happens only on devices with multicore CPU, if GLideNHQ can detect number of cores.

[gonetz]

Fixed.