Playing around with RGB/Scanline-Effect

lomaxx · 19 July 2009, 18:11

Hi. This is nothing special, but since i love the scanline- and RGB-subpixel-effects of TVs and very old crt-monitors, i have been playing around trying to simulated the effect with layers in gimp so that i could rather quickly apply it to any screenshot.

I am trying to get close to the real thing.

Well somewhat. Because of that i increased the resolution 3x, so that every pixel consists of 3x3 pseudo-subpixels. Then i added a layer that filters RGB out - red for the 2nd and 3rd, green for the 1st and 3rd and blue for the 1st and 2nd. On top of that i added another layer for a scanline-effect.

Unfortunately it's been quite some while since i sat in front of my real amiga with the old monitor, so i am not really aware of how good my result is. Of course it is a lot darker than the starting-image. So far i didn't add a blur or something like a glint to neighboured pixels. I am not sure if that would improve it. Comments are welcome.

Oh and be sure to look at the pictures 1:1 (original resolution, not zoomed). Otherwise it looks messed up.

Here is the original image (resized 3x):

<Edit: image removed. Please see here for a comparison.>

And here the same picture with the effect turned on:

<Edit: image removed. Please see here for a comparison.>

alexh · 19 July 2009, 18:41

Pretty cool...

You think you can get a similar effect out of WinUAE filters?

The only thing you're missing is a slight colour/intensity bleed into adjacent pixels

lomaxx · 19 July 2009, 19:14

Thanks for the reply.

I am not sure whether you mean if it can be done with the current filters in WinUAE or theoretically. I am on Linux for some years, so i do not know too much about the current stat of WinUAE. Is there some sort of script-language to create your own filters in WinUAE? I will try to update my knowledge about that topic. If it only could be done by rather conventional coding, then i am very likely overburdened with it. Unfortunately i can't code.

The biggest problem is probably that you need 3x the resolution of the original resolution. Which would exceed most monitors.

As for the bleeding: Maybe i will try to experiment with that later.

Toni Wilen · 19 July 2009, 19:16

WinUAE 1.6.2b1 new D3D "scanline" texture implementation can be easily replaced with static image(s) from file. (for example png with alpha-channel)

Perhaps in next beta..

lomaxx · 19 July 2009, 19:34

Sounds very cool. Then it could be done rather easy:

- buy a monitor that can display (most common amiga-resolutions)x3 (maybe we have to wait some more years until prices drop)
- create a texture of 3x3 showing three columns (red,green,blue) and apply it by using "multiplication".
- create a texture of 3x1 with one dot black and apply it on top of everything with the opacity of your choice

By the way: Which resolution(s) are the most common amiga-games/-demos using?

lomaxx · 19 July 2009, 19:47

I got the answer myself: 720x576 (the one i have been used to know)

http://eab.abime.net/showthread.php?p=254509

So the monitor would have to be able to display 2160x1728

Toni Wilen · 19 July 2009, 19:50

Most games are 320x200/320x256 (or slightly bigger if overscan)

lomaxx · 19 July 2009, 20:24

hm now i only wonder, when that feature will be available for uae or e-uae.

(yeah, i know that this will take ages, if ever)

Rabbit80 · 20 July 2009, 17:59

I hate scanlines effects

My old monitor / TV was NEVER that dark! Otherwise - good work!

alexh · 20 July 2009, 18:54

Quote:

Originally Posted by Rabbit80

My old monitor / TV was NEVER that dark!

Just like a TV the brightness of the colours can be increased.

lomaxx · 21 July 2009, 16:20

I noticed that the result is much better when i do not use strict RGB-colors (ff0000,00ff00,0000ff) for the RGB-mask, but mixed colors (ffb5b5,b5ffb5,b5b5ff). Also i tried adding a very slight gaussian blur:

I just wonder how i could easily apply that bleeding effect and if it would look good.

galu · 23 July 2009, 13:28

(FYI) I've grabbed some screenshots from DOSBox 0.73 and from Stella (Atari VCS/2600 emulator).

DOSBox
(no artifacting, double resolution)
http://www.galu.info/download/vga/dosboxHERC.png
http://www.galu.info/download/vga/dosboxEGA.png
http://www.galu.info/download/vga/dosboxSVGA.png

Stella (Atari VCS/2600)
(texture/afterimage/color bleed/noise, requires GLSL & slow as hell)
http://www.galu.info/download/vga/stella1.png
http://www.galu.info/download/vga/stella2.png

In contrast, simple NTSCfilter-like artifacting w/scanlines in Atari800 (VGA resolution only)
http://www.galu.info/download/vga/atari800sdl1.png
http://www.galu.info/download/vga/atari800sdl2.png

alexh · 23 July 2009, 13:59

Some very interesting effects.

lomaxx · 23 July 2009, 14:08

Thank you for the links, galu. Quite helpfull for my little, personal 'research'.

19 July 2009, 18:11	#1
lomaxx Registered User Join Date: Sep 2006 Location: Germany Posts: 43	Playing around with RGB/Scanline-Effect Hi. This is nothing special, but since i love the scanline- and RGB-subpixel-effects of TVs and very old crt-monitors, i have been playing around trying to simulated the effect with layers in gimp so that i could rather quickly apply it to any screenshot. I am trying to get close to the real thing. Well somewhat. Because of that i increased the resolution 3x, so that every pixel consists of 3x3 pseudo-subpixels. Then i added a layer that filters RGB out - red for the 2nd and 3rd, green for the 1st and 3rd and blue for the 1st and 2nd. On top of that i added another layer for a scanline-effect. Unfortunately it's been quite some while since i sat in front of my real amiga with the old monitor, so i am not really aware of how good my result is. Of course it is a lot darker than the starting-image. So far i didn't add a blur or something like a glint to neighboured pixels. I am not sure if that would improve it. Comments are welcome. Oh and be sure to look at the pictures 1:1 (original resolution, not zoomed). Otherwise it looks messed up. Here is the original image (resized 3x): <Edit: image removed. Please see here for a comparison.> And here the same picture with the effect turned on: <Edit: image removed. Please see here for a comparison.> Last edited by lomaxx; 21 July 2009 at 16:59.

21 July 2009, 16:20	#11
lomaxx Registered User Join Date: Sep 2006 Location: Germany Posts: 43	I noticed that the result is much better when i do not use strict RGB-colors (ff0000,00ff00,0000ff) for the RGB-mask, but mixed colors (ffb5b5,b5ffb5,b5b5ff). Also i tried adding a very slight gaussian blur: I just wonder how i could easily apply that bleeding effect and if it would look good. Last edited by lomaxx; 21 July 2009 at 17:02.

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19 July 2009, 18:41	#2
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,337	Pretty cool... You think you can get a similar effect out of WinUAE filters? The only thing you're missing is a slight colour/intensity bleed into adjacent pixels

19 July 2009, 19:14	#3
lomaxx Registered User Join Date: Sep 2006 Location: Germany Posts: 43	Thanks for the reply. I am not sure whether you mean if it can be done with the current filters in WinUAE or theoretically. I am on Linux for some years, so i do not know too much about the current stat of WinUAE. Is there some sort of script-language to create your own filters in WinUAE? I will try to update my knowledge about that topic. If it only could be done by rather conventional coding, then i am very likely overburdened with it. Unfortunately i can't code. The biggest problem is probably that you need 3x the resolution of the original resolution. Which would exceed most monitors. As for the bleeding: Maybe i will try to experiment with that later.

19 July 2009, 19:16	#4
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,505	WinUAE 1.6.2b1 new D3D "scanline" texture implementation can be easily replaced with static image(s) from file. (for example png with alpha-channel) Perhaps in next beta..

19 July 2009, 19:34	#5
lomaxx Registered User Join Date: Sep 2006 Location: Germany Posts: 43	Sounds very cool. Then it could be done rather easy: - buy a monitor that can display (most common amiga-resolutions)x3 (maybe we have to wait some more years until prices drop) - create a texture of 3x3 showing three columns (red,green,blue) and apply it by using "multiplication". - create a texture of 3x1 with one dot black and apply it on top of everything with the opacity of your choice By the way: Which resolution(s) are the most common amiga-games/-demos using?

19 July 2009, 19:47	#6
lomaxx Registered User Join Date: Sep 2006 Location: Germany Posts: 43	I got the answer myself: 720x576 (the one i have been used to know) http://eab.abime.net/showthread.php?p=254509 So the monitor would have to be able to display 2160x1728

19 July 2009, 19:50	#7
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,505	Most games are 320x200/320x256 (or slightly bigger if overscan)

19 July 2009, 20:24	#8
lomaxx Registered User Join Date: Sep 2006 Location: Germany Posts: 43	hm now i only wonder, when that feature will be available for uae or e-uae. (yeah, i know that this will take ages, if ever)

20 July 2009, 17:59	#9
Rabbit80 Its hard being famous! Join Date: Aug 2008 Location: Gateway to the dales, UK Age: 43 Posts: 633	I hate scanlines effects My old monitor / TV was NEVER that dark! Otherwise - good work!

23 July 2009, 13:28	#12
galu Registered User Join Date: Aug 2004 Location: Poland Posts: 121	(FYI) I've grabbed some screenshots from DOSBox 0.73 and from Stella (Atari VCS/2600 emulator). DOSBox (no artifacting, double resolution) http://www.galu.info/download/vga/dosboxHERC.png http://www.galu.info/download/vga/dosboxEGA.png http://www.galu.info/download/vga/dosboxSVGA.png Stella (Atari VCS/2600) (texture/afterimage/color bleed/noise, requires GLSL & slow as hell) http://www.galu.info/download/vga/stella1.png http://www.galu.info/download/vga/stella2.png In contrast, simple NTSCfilter-like artifacting w/scanlines in Atari800 (VGA resolution only) http://www.galu.info/download/vga/atari800sdl1.png http://www.galu.info/download/vga/atari800sdl2.png

23 July 2009, 13:59	#13
alexh Thalion Webshrine Join Date: Jan 2004 Location: Oxford Posts: 14,337	Some very interesting effects.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

23 July 2009, 14:08	#14
lomaxx Registered User Join Date: Sep 2006 Location: Germany Posts: 43	Thank you for the links, galu. Quite helpfull for my little, personal 'research'.