xBR algorithm tutorial

RetroArch Additions Shaders
#21

Hi Hyllian,

Could you post it on pastebin so i can test it out, all the file sharing sites are blocked for me unfortunately.

Regards,

Spin

#22

Sure. Iā€™ll give three shaders. Two are hybrid-crt candidates e and the last is a naked hybrid.

crt1: http://pastebin.com/q5bySjs4 crt2: http://pastebin.com/ku7tRvRc last: http://pastebin.com/yf4xJxF5

Iā€™d like to know which of the crt versions do you like more.

#23

I think crt1 looks slightly better. crt2 seems a little more prone to odd behavior where scanlines intersect with in-game lines.

#24

Hi, hunterk.

Could you use these two parameters from CRT1 in the CRT2 shader and see if the odd behaviors disappear?

    #define SPOT_HEIGHT 0.54
    #define COLOR_BOOST 1.48
#25

@Hyllian That didnā€™t seem to fix it.

Hereā€™s a picture showing the issue: http://www.mediafire.com/download.php?t853jek3dc3jbbj

Itā€™s in PSD format, but GIMP should open it, too, if you donā€™t have Photoshop. Toggle the visibility of the top layer, which is crt1 and it will make the background layer, crt2, visible with circles drawn around some of the problem spots.

#26

Are you sure itā€™s running at 1024x896? By the picture, Iā€™d say itā€™s a resolution issue.

These xBR-derived filters only work properly with integer multiple scale.

#27

That could be. The pictures were taken in windowed mode, so I would assume I had set an even integer scale, but I can double-check.

#28

It looks great, i cannot see a huge difference between CRT1 and 2. CRT1 does seem to look more clear to me.

#29

Two more for tests:

Hybrid: http://pastebin.com/7mgmDPvi

CRT: http://pastebin.com/aBNLk9pb

Use the same config recommendations I made before.

This new hybrid is more clean than the last version (v4). Some comparison: http://minus.com/mbc77JLTpfZqQs

#30

Thanks Hyllian, once i have some time i shall test it.

#31

Thereā€™s another shader Iā€™m working called ddt.cg.

Today I tweaked a bit and added gamma correction based on ideas from someone from other forum. I think the results are interesting.

Hereā€™s a beta: http://pastebin.com/cJ9TPbHU

#32

And now a ddt+gamma using xBR edge detection: http://pastebin.com/pZwerMr0

#33

Added gamma correction to xBR:

https://github.com/libretro/common-shaders/tree/master/xBR

Theyā€™re the three files with ā€œgammaā€ in the name.

#34

I just found an improved rule to detect corners. It gets the quality of C version without most of its artifacts.

Iā€™m implementing in shader only: http://pastebin.com/QMR4De9a

#35

If the last version doesnā€™t work in your GPU, try this 3.7 modificated:

http://pastebin.com/iwX9u4eB

#36

It looks good on my AMD/ATI card. Iā€™ll try it on Intel tomorrow.

#37

Have you noticed improvements over 3.7c? (ex.: Super Mario World coins).

#38

Added those two shaders to the repo:

https://github.com/libretro/common-shaders/blob/master/xBR/4xBR-v3.9.cg https://github.com/libretro/common-shaders/blob/master/xBR/5xBR-v3.7d.cg

#39

The first LEVEL3 xBR shader is done!

An example is the Megaman X2 ramp, with LEVEL3 4.0 it get rid of macro jaggies:

http://imgur.com/m9UfqQA

On the repo (4xBR-v4.0 and 5xBR-v4.0): https://github.com/libretro/common-shaders/commit/c428ad0b4f01b45f6c0d63840175b9d8a6ce29a5

#40

On my Radeon card, itā€™s getting some weird multicolor noise artifacts in the image: On the other hand, you can see from the inclined portion of the ground that itā€™s doing an amazing job of smoothing out those previously uncorrectable jaggies :open_mouth: