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ilmenit

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It's odd. Why is the converter doing this?

You have a picture with 11 colours at the 160x240 resolution.... indexed colour BMP . Everything should go like drinking a good beer in the desert.

But the picture gets 23 colours there... 5 greys instead of 3 greys, 6 browns instead of 3 browns... 5 reds instead of 3...

 

Atari and C64 have different graphics possibilities. The converter is not able to set the exact colors at exactly the same places.

Therefore it chooses other color to cover some area that minimizes error.

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Btw, here is a little tutorial how do I preconvert pictures when the standard preprocessing and dithering implemented in RastaConverted gives bad results.

 

This tutorial uses two freeware tools: Timanthes and IrfanView.

 

Let's say that we have a picture:

post-22831-0-42826300-1339434056_thumb.png

Preprocessed by RastaConverter gives a destination picture that looks bad - it is too gray and large background areas are not dithered correctly:

post-22831-0-56164500-1339434057_thumb.png

 

First we have to set Timanthes to use Atari palettes. To do it open the Palettes Folder:

post-22831-0-49264700-1339434058_thumb.png

and copy *.txt from TimanthesPalettes.zip there.

Those are 128 color palettes that RastaConverter is using (You can convert other .act palette to .txt files with the tool from the archive).

 

Then you have to make sure that the input picture is 24 bit - if it's only 8bit then the color remapping process will not work correctly.

To do it use IrfanView:

post-22831-0-67212900-1339434061_thumb.png

post-22831-0-49076500-1339434062_thumb.png

 

We should also resize the picture to 320x240 pixels (or different height if needed) - it's usually good to "apply the sharpen after Resample" to make contours more visible.

post-22831-0-39853000-1339434063_thumb.png

Save the picture.

 

Now we should have it in proper size and in 24bit:

post-22831-0-95287100-1339434065_thumb.png

 

Open the file in Timanthes and choose the desired palette file:

post-22831-0-18230500-1339434795_thumb.png

 

Then choose from the menu Layer->Reduce Colors:

post-22831-0-70004400-1339434857_thumb.png

 

Set the palette to 'Current' - it will use chosen Atari palette. Use "Wide Pixels". Set method to 'Exact' (you may try other options).

Then experiment with the brightness dithering and saturation for the best result.

post-22831-0-67657500-1339434858_thumb.png

 

The output picture should look much better now:

post-22831-0-26767000-1339434859_thumb.png vs previous post-22831-0-56164500-1339434057_thumb.png

 

Use the picture in RastaConverter with /filter=box parameter to import it without resampling:

RastaConverter.exe tut9.png /filter=box /pal=laoo /distance=ciede

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It's odd. Why is the converter doing this?

You have a picture with 11 colours at the 160x240 resolution.... indexed colour BMP . Everything should go like drinking a good beer in the desert.

But the picture gets 23 colours there... 5 greys instead of 3 greys, 6 browns instead of 3 browns... 5 reds instead of 3...

 

Atari and C64 have different graphics possibilities. The converter is not able to set the exact colors at exactly the same places.

Therefore it chooses other color to cover some area that minimizes error.

 

Sorry, but that's not what it is doing. As the import picture already has the exact palette values. The colours are imported by some "dither" that isn't obvious where it turns in.

 

And, btw. C64 has LESS colours than the A8, particular here, you find a fitting colour everytime.

 

 

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The colours are imported by some "dither" that isn't obvious where it turns in.

And, btw. C64 has LESS colours than the A8, particular here, you find a fitting colour everytime.

 

1. Maybe Wrathchild forgot to use the /filter=box parameter? Without it resampling will add additional colors.

2. On C64 colours can be placed on different places on screen than on Atari.

3. RastaConverter is not limited to use only the palette from the original picture, but the whole Atari palette to minimize error. Emkay, you should understand finally how the optimization process works. It is well described in first posts about RastaConverter...

Edited by ilmenit
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Too explain it with this image....

 

Originally less than 16 colours, it now has almost 30 colours. This progress happens everytime.

 

post-2756-0-16957000-1339437652_thumb.jpg

 

Look at the red marks...

 

1. There is clearly a "gold" with an approximated different brightness. This colour is not in the import picture. Now it stands there and won't be removed.

 

2. The colour is wrong, the converter leaves it untouched, because it's "close enough" ?!?

 

3. The dark red will never leave... same as point 2.

 

 

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If RastaConverter never removes this kind of line, then maybe some register (X,Y,A) is used for both sprite position and color value?

I will add in the next version and option to limit output palette to input palette only. It will help with the low color pictures.

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WTF!!! Is this still Atari 8bit GFX???

 

nope. It's just a preprocessed picture to be converted to Atari 8bit. It will look worse for sure.

How much worse we will see tomorrow (the picture is under conversion now).

Edited by ilmenit
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1. Maybe Wrathchild forgot to use the /filter=box parameter? Without it resampling will add additional colors.

No, I do use 'box'.

Emkay I take it from the QueDex that you've used the c64.act file AND set the palette in your source picture accordingly?

I'm looking at some other C64 pics and their RGB values for the 16 (or less) colours are quite various!

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1. Maybe Wrathchild forgot to use the /filter=box parameter? Without it resampling will add additional colors.

No, I do use 'box'.

Emkay I take it from the QueDex that you've used the c64.act file AND set the palette in your source picture accordingly?

I'm looking at some other C64 pics and their RGB values for the 16 (or less) colours are quite various!

 

Que-Dex at 70K evals... with adjusted colours...

 

post-2756-0-03947700-1339446324_thumb.png

 

quedex70K.xex

 

(mean 70KK ... 70Million :) )

 

 

It's no prob to finish it, when the generator keeps the colours stable.

Edited by emkay
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I'm looking at some other C64 pics and their RGB values for the 16 (or less) colours are quite various!

 

That's why we shouldn't take a look at the source colours that much , if they were indexed already.

Real colours, yes, Atari-Palette colours, ofcourse.

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Emkay I take it from the QueDex that you've used the c64.act file AND set the palette in your source picture accordingly?

 

 

It took a while to understand this sentence :)

I'm not using the C64.ACT, because it doesn't work here. I'm adjusting the colours of the pictures by hand, getting the palette values from the palette (read from G2F), and save the picture as a 4 bit bitmap.

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Which is what I was saying by providing the rgb values used in the palette, but QueDex seemed odd as the browns were different in it's palette and so if we come up with a definitive C64 rgb set, then an act file can be made from that and pictures adjusted up front accordingly.

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I think this nice C64 image will be beyond the A8, here I've flipped the image horizontally to try and encourage the face to be concentrated upon but still no joy :( Others screens that also struggle... QueDex loader & Ballistix

This images using 3 different color palettes.

BALLISTIX_1.gif using C64HQ palette.

Prowler.png using PEPTO palette (probably most faithful color palette C64).

Que-Dex-C64.gif using CCS64 palette.

 

Your images vs the same images with PEPTO palette:

examplesx.png

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I only can propose that it is irreleavant, what RGB values the C64 colours have. Just use a colour of the RGB range.... and good....

 

Here some other "C64 screenshots"...

 

http://www.mobygames.com/game/c64/mind-roll/screenshots/gameShotId,183126/

 

https://www.google.de/search?hl=de&q=quedex+c64+bild&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&biw=1143&bih=985&wrapid=tlif133948265547810&um=1&ie=UTF-8&tbm=isch&source=og&sa=N&tab=wi&ei=L-LWT7PnNszptQbz18G6Dw

 

 

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Your images vs the same images with PEPTO palette

 

So here you have just updated the image with the RGB values from a more common palette and these are not the RastaConverted outputs? How is that new from what I proposed in posts 510/514?

 

Do you have a PEPTO act file for RastaConverter to use? Where are the 16 C64 RGB colours positioned in that file? If they fill the first 16 entries then although RasterConverter will show you the correct colours whilst producing the image... once converted to an xex you then see a grey scale image under emulation / on a real machine.

 

Maybe sometime this week I'll have a stab at dynamically making the target palette from the imported picture's palette (allowing the user to specify the usual A8 act palettes).

 

Even so, sometimes the 'seemingly' most simple things aren't picked up by the application, for example with this World Class Leaderboard screen, the vertical grey/white bars take an age to resolve... this is after 160M evaluations.

post-1822-0-07126200-1339488223_thumb.png

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I mean honestly. How can a computer program work better than the human brain? this is an automatic tool. so actually there should be the possibilities to import in G2F or in a GUI where you can adjust all you guys have discussed?

 

We're just trying to help producing the tool. If it was a bad thing, no one was using it.

But it has some problems which would be useful to solve them.

 

post-2756-0-36293800-1339508646_thumb.png

 

alpha.xex

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yup. pushing stuff is good so let's see where we can bring RastaConverter. Btw. Interesting thing is while watching the hungarian demo scene video on youtube. Converters seem to be even be used on c64 scene as pixel artists want to use their Windows/Mac painting tools without thinking all the times about the limitations of the hardware. so maybe RastaConverter goes the same way.

 

Not sure what is the best approach. Setting pixels by hand and knowing all limitations of the hardware (and all possible things like with G2F) or do it on painting program and then run converters and simply optimise the output here and there.

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