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What is DHGR really capable of? Not content with existing A2 graphic converters? [message #340204 is a reply to message #340202] |
Sat, 25 March 2017 11:03 |
zellyn
Messages: 173 Registered: April 2013
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A couple of further thoughts after reading the whole thing.
1. If you have a Mac, definitely give 4am's OpenEmulator build a try: I think you'll be astonished at just how good the NTSC emulation is: choose the color monitor with all the settings, and you can tweak away until it matches what you're seeing on your actual CRT. You need 4am's build because my IIe changes are still in progress...
2. I have been thinking of porting the OpenEmulator NTSC emulation to a standalone library, to a web GL shader, and to non-gpu normal Go code. Sounds like I should get busy!
3. I've been wondering about the idea of dithering and DHGR as a maximization problem: use the NTSC emulation to render; then score the difference from the rendered image using a weighted combination of gaussian blurs of different radii, and possibly some edge detectors; then just randomly toggle bits and accept changes that improve the score. If anyone here understood this paragraph and has ideas, thoughts, suggestions, or pointers to literature, let me know :-)
Zellyn
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Re: What is DHGR really capable of? Not content with existing A2 graphic converters? [message #340216 is a reply to message #340203] |
Sat, 25 March 2017 13:29 |
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Originally posted by: Mark D. Overholser
On 3/25/2017 07:38, Nicola wrote:
> On 25/03/2017 14:51, Lukazi wrote:
>> Hi All,
>>
>> I've spent the last few months trying to see what Double High
>> Resolution Graphics (DHGR) is really capable of. It's a work in
>> progress but the results look promising.
>>
>> http://lukazi.blogspot.com.au/2017/03/double-high-resolution -graphics-dhgr.html
>>
>
> I am really impressed by what you guys are doing with Apple ][ graphics
> (you, B. Buckels, and all the other people already mentioned).
>
> I wonder if anyone has thought of combining such good images with a good
> plot for a text&graphics adventure game.
>
> Nicola
I have...
My focus is Networked Games, of the Text, Text/Graphics and Graphics
variety.. So, if they can be Networked, they Could also be Stand Alone..
MarkO
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Re: What is DHGR really capable of? Not content with existing A2 graphic converters? [message #340217 is a reply to message #340204] |
Sat, 25 March 2017 15:02 |
Michael J. Mahon
Messages: 1770 Registered: October 2012
Karma: 0
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Senior Member |
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Zellyn <zellyn@gmail.com> wrote:
> A couple of further thoughts after reading the whole thing.
>
> 1. If you have a Mac, definitely give 4am's OpenEmulator build a try: I
> think you'll be astonished at just how good the NTSC emulation is: choose
> the color monitor with all the settings, and you can tweak away until it
> matches what you're seeing on your actual CRT. You need 4am's build
> because my IIe changes are still in progress...
>
> 2. I have been thinking of porting the OpenEmulator NTSC emulation to a
> standalone library, to a web GL shader, and to non-gpu normal Go code.
> Sounds like I should get busy!
>
> 3. I've been wondering about the idea of dithering and DHGR as a
> maximization problem: use the NTSC emulation to render; then score the
> difference from the rendered image using a weighted combination of
> gaussian blurs of different radii, and possibly some edge detectors; then
> just randomly toggle bits and accept changes that improve the score. If
> anyone here understood this paragraph and has ideas, thoughts,
> suggestions, or pointers to literature, let me know :-)
>
> Zellyn
>
Several times in the past I've suggested that a shift register long enough
to span a microsecond or so (14 to 16 bits) would capture enough "video
context" to nicely emulate NTSC processing.
The (say) 16 bits would index R, G, and B tables computed from the DSP
emulation of NTSC processing, so you'd have the color rendering of real
NTSC with only a table lookup that should be trivial on modern processors.
The point of using a longer-than-usual shift register is that for faithful
NTSC rendering, it's necessary to span enough time to cover the
approximately 1MHz bandwidth of the chrominance filters.
--
-michael - NadaNet 3.1 and AppleCrate II: http://michaeljmahon.com
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Re: What is DHGR really capable of? Not content with existing A2 graphic converters? [message #340257 is a reply to message #340201] |
Sun, 26 March 2017 01:03 |
STYNX
Messages: 453 Registered: October 2012
Karma: 0
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Senior Member |
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On Saturday, March 25, 2017 at 3:02:15 PM UTC+1, Bill Buckels wrote:
> "Lukazi" <lu...@hotmail.com> wrote:
>> I've spent the last few months trying to see what Double High Resolution
>> Graphics (DHGR) is really capable of.
>
> When you find-out let me know... so far yours are roughly equal to what
> Sheldon Simms, Blurry, and I have produced. Good article too...
>
> The DHGR converters that we have today produce infinetly superior results
> than anything historically produced in the 80's and 90's that I am aware of.
>
> Bill
I think that Sheldon has gone bit further than the currently possible. The Images are near photo realistic.
Bill, your implementation is very good and easy to use but Sheldon took the NTSC artifacts into his conversion. If we could combine your work with his work and D. Brock puts it into the buckshot or something :-)
Its that a standard A2e can produce nicer images than the C64 :-P
-Jonas
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Re: What is DHGR really capable of? Not content with existing A2 graphic converters? [message #340595 is a reply to message #340257] |
Wed, 29 March 2017 13:22 |
BLuRry
Messages: 489 Registered: October 2012
Karma: 0
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Senior Member |
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On Sunday, March 26, 2017 at 12:03:49 AM UTC-5, STYNX wrote:
> On Saturday, March 25, 2017 at 3:02:15 PM UTC+1, Bill Buckels wrote:
>> "Lukazi" <lu...@hotmail.com> wrote:
>>> I've spent the last few months trying to see what Double High Resolution
>>> Graphics (DHGR) is really capable of.
>>
>> When you find-out let me know... so far yours are roughly equal to what
>> Sheldon Simms, Blurry, and I have produced. Good article too...
>>
>> The DHGR converters that we have today produce infinetly superior results
>> than anything historically produced in the 80's and 90's that I am aware of.
>>
>> Bill
>
> I think that Sheldon has gone bit further than the currently possible. The Images are near photo realistic.
> Bill, your implementation is very good and easy to use but Sheldon took the NTSC artifacts into his conversion. If we could combine your work with his work and D. Brock puts it into the buckshot or something :-)
>
> Its that a standard A2e can produce nicer images than the C64 :-P
>
> -Jonas
The Outlaw converter also takes artifacts into account. It's a bit sloppy but essentially it does a brute-force match for every bit position and does a total error distance function to see if turning a bit on or off is a closer "match" to the desired pixels in the whole area (not just the target pixel it affects) For HGR, this is done for both hi and lo order combinations and the winner is chosen after both closest matches are calculated. The error propagation is performed once the winner is chosen. This has interesting side effects like it selecting the combinations of HGR bytes that yield pixels that are 25% or 75% width such as the occasional brown or yellow.
I can't pretend to be an expert, but I decided the best thing to do is let folks adjust the error correction rules to suit their fancy. All the error propagation rules are tweakable so you can pick Fast-Floyd-Steinberg or Atkinson, etc. I would say that it's worth desaturating an image a litte bit before trying to convert it or mess with brightness/contrast of the original as it can help surface better detail in the conversion.
I recently added an option to Outlaw which lets you export a full HGR or DHGR screen as a monitor listing to the clipboard. Previously it would save the binary data as a file but that was probably not as convenient. There's been other improvements to the drawing mode to speed things up a little and have multiple levels of undo as well as working zoom controls. It's not perfect but it works.
-B
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Re: What is DHGR really capable of? Not content with existing A2 graphic converters? [message #340603 is a reply to message #340203] |
Wed, 29 March 2017 13:29 |
BLuRry
Messages: 489 Registered: October 2012
Karma: 0
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Senior Member |
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On Saturday, March 25, 2017 at 9:38:09 AM UTC-5, Nicola wrote:
> On 25/03/2017 14:51, Lukazi wrote:
>> Hi All,
>>
>> I've spent the last few months trying to see what Double High
>> Resolution Graphics (DHGR) is really capable of. It's a work in
>> progress but the results look promising.
>>
>> http://lukazi.blogspot.com.au/2017/03/double-high-resolution -graphics-dhgr.html
>
> I am really impressed by what you guys are doing with Apple ][ graphics
> (you, B. Buckels, and all the other people already mentioned).
>
> I wonder if anyone has thought of combining such good images with a good
> plot for a text&graphics adventure game.
>
> Nicola
OR what about an RPG? This is how we made the graphics for Ancient Legends.. Most of the graphics were scanned from out-of-copyright or otherwise public domain images and then touched-up by hand. A lot of the images, even in HGR, have nice smoothed anti-aliased edges and so on, a nice artifact of this kind of conversion process.
-B
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