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Altirra 4.00 released


phaeron

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https://www.virtualdub.org/beta/Altirra-4.10-test5.zip
https://www.virtualdub.org/beta/Altirra-4.10-test5-src.7z

  • Fixed bugs with monochrome modes not working with VBXE or high artifacting modes. Unfortunately this fix also results in the return of some chroma artifacts in NTSC high artifacting mode that were previously being incorrectly canceled; I may try to retune the artifacting filters again at some point.
  • Tape editor: fixed broken CAS saves after some edits, highlight and scroll to changes on undo, add menu option and shortcut to re-run decoding analysis after doing an edit, redo FSK decoding in the tap editor to be closer to regular emulation decoding to increase reliability, shift+click now only moves the endpoint of the selection, warn when standard blocks will be converted to FSK on CAS save, and optimize FSK blocks on save.
  • C: SIO patch now supports disabling the timeout with DTIMOT=0, which fixes some tapes that had extremely long blocks (>4.5 minutes).
  • Added support for loading PWM-encoded chunks in CAS files.

 

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  • 2 weeks later...

Avery,
simple question - how can I manipulate RD5/TRIG3 from console while emulating 800XL and higher?
Some czech cartridges were using this technique for various loaders. This simplest was just a switch on RD5 line, so you had cartridge inserted, and when you needed coldboot you pressed the button, pushed RESET, cart copied itself to RAM and then you released the button. I just want to test something and currently removing cartridge does coldboot, and I can't find any way how to manipulate RD5/TRIG3. (Checked the source, installed 4.10-test4 etc).

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Holy crap, I just discovered that I was able to select text in Altirra just like a text editor... that's super impressive! ?

 

I know the developer isn't a fan or CRT emulation (even though I personally don't make a distinction between that and the visual artefacts already emulated), but the sharp edge is frankly a bit jarring:

 

image.png.5bcd55406f1ed5ca208d9f1952c634e5.png

 

Is there an option to blur the edge a bit and perhaps even add a corner radius, or if there isn't could it be considered for a future version?

 

 

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On 11/14/2021 at 1:04 PM, drpeter said:

Not just the best emulator but in the top 5 freeware applications of all time, for me ❤️.

 

Thanks, Avery.

I agree and Virtualdub is also in the top 5 in my book. I used it for years combine with an Osprey-210 to capture movies from my cable box. I had another small application that managed the timer and started Virtualdub for the recording.

 

Avery is a top notch programmer!

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4 hours ago, flashjazzcat said:

This is straight off a Commodore 1084S over RGB. What calibre of CRT are we actually talking here? :)

Yeah, I must admit I'm not a fan of people posting best-in-class CRT stuff these days. Back in the 80s, an average person could probably not afford that.

 

I really like CRT effect made by Mattias Gustavsson, because it can emulate really crappy TVs which is what most people had: https://mattiasgustavsson.itch.io/steem-crt

 

It's open source and ready for use, but I already suggested this once before and got shot down, unfortunately. :)

 

Anyway, crossing my fingers for blurred and rounded borders at least!

Edited by eobet
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No one should be shot down for making a suggestion, I quite liked the version of Steem with it. As always, it's down to the tech side of the emulator and what Avery thinks of the idea. Already said what I'd like, I think it would round off the look of the already sumptuous emulator but me aint doing the coding :)

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IDK.. I'm rather happy with the way the display is now. It's almost like what we all wanted back in the day. A sharper and higher quality display overall. Happy there's no CRT geometry distortion. That's a biggie, no annoying curves and warpage. But I wouldn't mind some extra NTSC fuzzy effects to play around with, like Stella and Atari 800 Emulator use.

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It's all a bit individual, some want the HDMI look, some want the old TV look, some like me want something in-between and that's what I have as it stands. A rounded corner would be really nice just to give that old TV / Monitor look but if it happens great, if not then I'm still fine as I have real hardware to play off my 4:3 Philips monitor (perfect). Should I ever lose my hardware then I'll still be over the moon with the greatness that is Altirra.

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31 minutes ago, eobet said:

Yeah, I must admit I'm not a fan of people posting best-in-class CRT stuff these days. Back in the 80s, an average person could probably not afford that.

Sure: I used the A8 with a 12" portable TV over RF the entire time until I bought CRT monitors ten years ago, but the picture quality over RF was so appalling I can't say I miss it. I rather think a 1084 or 1702 would represent the 'retro' visual experience now, but if an 'RF' filter is what's being requested, fair enough. I should probably get some photos of Y/C video on the 1084 as well, in fairness.

 

I happen to think Altirra's existing CRT emulation features are pretty good; scan lines and bloom seem to equate pretty closely to what I'm seeing on a real tube. It's also possible to run custom filters (which I once tried, and I forget how it's set up); perhaps that would accomplish what's being requested.

 

Note I speak from the point of view of an ardent Altirra user who nevertheless switches on real hardware when I want to look at real hardware. :)

 

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I never had a TV that wasn't adjusted to deliver a nice picture from the Atari, some of them were literally from the garbage... Almost all of them could be adjusted if a person chose to do so, or take them to a shop and have it done... yes the cover had to come off to do so on many... I'm worried about folks whom didn't have the geometry taken care of... how much of the picture they must have missed or viewed in some distorted way... emulating a defective CRT or other improperly set up display seems a bridge that I wouldn't want to cross....

Edited by _The Doctor__
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Well I’m just happy that when a straight line is drawn it is really actually straight. Verifiable with a ruler. No curves, no bow, no punch, no keystone.. No curvature.. On standard readily available displays. Thanks to LCD tech in the digital domain.

 

Stella and MAME and Atari 800 Emulator have fuzzy NTSC effects, to soften it all up and add warmth, and that’s a real hoot! Dialing in noise via BGFX is just gorgeously nostalgic.

Edited by Keatah
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So, regarding the image itself -- I don't have anything planned currently. Older CRT emulations looked like vaseline smeared over the screen and weren't very compelling, some of the newer ones are good but would require porting. Also, for various reasons I typically do not use third party code in Altirra even if it is open source. Currently I've been focused more on color fidelity, though at some point I might loop back and try something phosphor-related.

 

Now, as for the border around the image -- that might be something I can do something about. Formerly this was difficult to do anything about because the curvature itself was done in the pixel shader and it would have been expensive to add border smoothing. However, for shader complexity reasons I recently rewrote the distortion to use a tessellated mesh instead, so an alpha border would be cheaper to add to smooth it off a little bit. Not sure I would try to round off the corners as in the end that might better done just with an overlay and I don't want to add yet another UI control just for the corner radius, but antialiasing the edge seems reasonable at least.

 

In practice, CRTs don't actually have that much distortion if viewed straight-on since they have circuits to compensate for the barrel effect. Just drawing a frame on top may actually be more accurate than pushing the distortion slider much.

 

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2 hours ago, phaeron said:

Older CRT emulations looked like vaseline smeared over the screen and weren't very compelling, some of the newer ones are good but would require porting.

Absolutely true.

 

2 hours ago, phaeron said:

Currently I've been focused more on color fidelity,

That's much appreciated. It's important and often taken for granted because of how subtle changes can be.

 

2 hours ago, phaeron said:

though at some point I might loop back and try something phosphor-related.

That could be interesting. Can you say more on it?

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5 minutes ago, Keatah said:

That could be interesting. Can you say more on it?

Just the usual, trying to replicate the effect of colored phosphors separated by an aperture grill.

 

There's a lot of subtlety in doing this right, including rendering the pattern with proper antialiasing and filtering, and probably linear lighting required. The pattern is fine enough that even on a modern high-resolution display some care is required to filter the fine lines properly. Bloom is another issue; Altirra does not render to an HDR framebuffer (16F linear) unless HDR is enabled for performance reasons, so that may complicate getting a good bloom out of such a fine pattern.

 

Phosphor persistence may be the other thing you're thinking of. It's a relatively simple effect to do -- similar to the frame blending filter -- but not one that seems very compelling. About the only monitor I remember using that had any really noticeable persistence was the old green Apple Monitor ///.

 

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On 1/5/2022 at 10:01 AM, jindroush said:

Avery,
simple question - how can I manipulate RD5/TRIG3 from console while emulating 800XL and higher?
Some czech cartridges were using this technique for various loaders. This simplest was just a switch on RD5 line, so you had cartridge inserted, and when you needed coldboot you pressed the button, pushed RESET, cart copied itself to RAM and then you released the button. I just want to test something and currently removing cartridge does coldboot, and I can't find any way how to manipulate RD5/TRIG3. (Checked the source, installed 4.10-test4 etc).

The settings available under System>Configure System>Ease of use will help you to prevent cold start when changing cartridge. To be honest, there are so many settings in the dialog that a settings search box (like in the Eclipse IDE) could be useful. But anyway, the life before the Configure System dialog was much harder than today.

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