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2009-05-02 13:47

Oswald

Registered: Apr 2002
Posts: 5017

More accurate CRT emulation

http://www.bogost.com/games/a_television_simulator.shtml

someone please make this for Vice :)

... 30 posts hidden. Click here to view all posts....

2009-05-02 21:47

MagerValp

Registered: Dec 2001
Posts: 1055

I've been flaming the original author a bit here:

http://www.atariage.com/forums/index.php?s=&showtopic=142886&vi..

It is indeed a half-assed attempt, but apparently they intend to expand on it later.

I'm annoyed and disturbed that people seem to think that making the LCD image shittyer makes it look more like a CRT, completely ignoring the fact that the image is *better* on the CRT in every respect except sharpness - and I think most people agree that sharp square pixels look like shit for the C64. TFTs are less capable displays[*], and there's just no way you can give it the color gamut or black levels of a CRT. What's left is trying to give it a bit of CRT's natural anti-aliasing, from dot pitch and shadow mask discrepancies, phosphor glow, etc, but what bugs me is that they don't appear to have done much in the way of research. Ian says that's there's more to it than eyeballing, but considering their implementation I wonder what...

They also seem to have mixed up effects from the signal encoding (i.e. blur from limited luma bandwidth, color bleed, RF noise), and effects from the CRT display (afterglow, pixel pattern, bloom). VICE's PAL emulation does a pretty good job with the signal encoding stuff, Blargg's NTSC libraries also do a nice job, but it'd be interesting if someone tried to look more seriously at CRT effects. Maybe we could get some nice scaling out of it, that isn't locked to 2x and with proper pixel aspect ratios?

[*] at least if we're talking consumer displays and not expensive pro stuff

2009-05-03 00:59

A Life in Hell
Account closed

Registered: May 2002
Posts: 204

Quote: Quote:
of all yet non-emulated things, the effect that bright (especially white) pixels appear "larger" is the most noticable and even a BAD emulation (as in make those exceed the scanline slightly) might make it LOOK more like a real TV.

this is one of the actual CRT effects - and caused by the dotmask. and as said the major problem is that the current architecture of the vice rendering pipeline does not allow to add the required fullframe filter. and once you have modified it so its possible you can just aswell implement it correctly :)

Quote:
I don't get why you'd want to make the picture worse.
IMHO, emulation is all about what the computer does, not what your crappy screen looked like back then.

many of the effects infact are about "what the computer does" (everything related to PAL emulation)

Quote:
so you use vice without PAL emulation all the time I suppose?

it's indeed shocking how many people do that (and for example advocate to not make pal emulation on per default)

I can see why people don't use palemu though.... the default palemu also enables nassive blur, which, uhm, sucks - it's a bad TV effect, ironically, rather than a c64 efffect. Of cpuirse, turning off blur and scanlines on the pal controls makes it ninjasweet

2009-05-03 07:08

Angel of Death

Registered: Apr 2008
Posts: 210

However honorable and fascinating this: "let's for nostalgic sake emulate my parents leftover, crappy, cheap-Taiwan build television" discussion is. It has nothing to do with CRT emulation.
And if PAL emulation doesn't cover the load then I suggest we call it: MY NOStalgicly Emulated TeleVision or MYNOSETV for short.

But, then again, it would be a nice idea to include PAL emulation in the emulators for the VCS, COLECO, Philips, etc. systems but that is for another forum.

2009-05-03 07:52

MagerValp

Registered: Dec 2001
Posts: 1055

Quote: I can see why people don't use palemu though.... the default palemu also enables nassive blur, which, uhm, sucks - it's a bad TV effect, ironically, rather than a c64 efffect. Of cpuirse, turning off blur and scanlines on the pal controls makes it ninjasweet

Didn't they dial it down a little a few releases ago, so it defaults to S-Video quality instead of Composite quality? The scanlines are still a bit too prominent IMHO, but it still looks a lot better out of the box with PAL emulation on.

2009-05-03 08:34

Mace

Registered: May 2002
Posts: 1799

Indeed, I have PAL emu off almost all of the time.
Not because I don't like the effect, but I like it better without it :)

2009-05-03 12:28

chatGPZ

Registered: Dec 2001
Posts: 11100

Quote:

it'd be interesting if someone tried to look more seriously at CRT effects. Maybe we could get some nice scaling out of it, that isn't locked to 2x and with proper pixel aspect ratios?

i did :) however like said above, the vice rendering architecture doesnt allow to easily add fullscreen filters, which you would need for dotmask/blooming etc

Quote:

the default palemu also enables nassive blur, which, uhm, sucks - it's a bad TV effect, ironically, rather than a c64 efffect.

no, its a pal effect. (limited bandwidth for chroma, chroma is valid for ~4 pixels) the only "crt effect" implemented in vice are the scanlines.

2009-05-03 13:03

JackAsser

Registered: Jun 2002
Posts: 1987

Quote: Quote:
it'd be interesting if someone tried to look more seriously at CRT effects. Maybe we could get some nice scaling out of it, that isn't locked to 2x and with proper pixel aspect ratios?

i did :) however like said above, the vice rendering architecture doesnt allow to easily add fullscreen filters, which you would need for dotmask/blooming etc

Quote:
the default palemu also enables nassive blur, which, uhm, sucks - it's a bad TV effect, ironically, rather than a c64 efffect.

no, its a pal effect. (limited bandwidth for chroma, chroma is valid for ~4 pixels) the only "crt effect" implemented in vice are the scanlines.

Quote:

i did :) however like said above, the vice rendering architecture doesnt allow to easily add fullscreen filters, which you would need for dotmask/blooming etc

Hmms. There is an option to render directly onto the primary directx surface or not. If not, then it's double buffered, that alone (at least to me! :D) suggests that there are a complete buffer somewhere which is swapped in, hence a potential place to add filtering. But then again, I havn't checked the source and you have Groepaz.

2009-05-03 13:28

chatGPZ

Registered: Dec 2001
Posts: 11100

the problem lies before that in the rendering queue... vice spends enornmous effort on never updating a single pixel that didnt change from the previous frame (and that means, no, its not actually properly double buffered at all). this even makes the relativly simple pal filter rather tricky, because you cant easily look at pixels that have already been drawn (the pal emu must buffer the previous line internally). but to implement something like "blooming" you'd also have to *update* pixels that "have already been drawn" (brightness propagates to all neighbour pixels). to make that possible all that pointless caching must be eliminated first :)

2009-05-03 13:45

Mace

Registered: May 2002
Posts: 1799

I haven't got a clue about PC programming, but... if you'd add the PAL effect on top of the screen, as an overlay, you can add the filter to unchanged pixels.
Can't you?

2009-05-03 14:00

chatGPZ

Registered: Dec 2001
Posts: 11100

ofcourse, thats pretty much how it'd work - very simply said. :) but its much easier said than done =P

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