9 replies to this topic

[Synthpopalooza]

Well, looks like my font editors won 4th place in ABBUC.

ICE is a series of font editors that work with special character-flip text modes that enable the display of extra colors onscreen through VBI swapping. There are 20 different graphics modes supported, which can display anywhere up to 256 colors onscreen at once.

Attached are three ATR's, plus the insctuction manual as a .PDF, and also some articles I wrote for AtariUser documenting most of these new Graphics modes.

To use ICE, I recommend any Atari with 64K RAM. You can run this on a PAL machine, but NTSC gets better results because of the faster refresh rate. For Emulation, Altirra is recommended. Atari800Win is not recommended because there are issues with displaying some of the CIN modes, and the screen flicker refresh rate is horrible on it.

The ATR's are:

iceirg.atr - Edits in Super 0, Super IRG, Super IRG 2, and DIN
icegtia.atr - Edits in the GTIA modes (including Super 9, Super 10/10+, APAC, and HIP)
icecin.atr - Edits in the CIN modes (3 variations each of CIN, MIN, and PCIN)

I will be working on updates to these programs as I get time, and also I am working on new ICE editors for the Super IRG modes based out of Graphics 1. Examples of these modes can be seen in this thread.

Some screenshots:

Attached Files

•  ice abbuc 1.0.zip   395.13K   41 downloads
•  super irg modes 2.zip   1.07MB   35 downloads
•  super irg modes.zip   1.35MB   36 downloads

[svenski]

Congrats!

[Stephen]

Congratulations - you've put a ton of effort into this. It's nice to see a development tool that runs on the little A8. PC tools are great, but there is something cool about doing dev work on the native machine too.

[Thorsten Günther]

Due to the complexity of the program, the ABBUC shipped a Sondermagazin (special magazine) with the complete instructions (in English, noone found the time to translate it) together with the disks and the regular magazine:

[Synthpopalooza]

I have some German speaking friends (and Polish) so I can have the manual translated if you like.

In fact, Kaz over on atarionline.pl has been translating my AtariUser articles on the ICE modes into Polish.

I guess this project has had a lot of effort, it's taken me 2 years of experimenting to get to this. I'll be really happy if, hopefully, some new games and demos come out of these ICE modes.

[atx4us]

Congratulations on your ABBUC award! Your perseverance to develop this program is admirable.

[therealbountybob]

Hi,
on my (130xe) PAL CRT tv all the programs flickered; I didn't get the nice displays you have above - are the programs usable on PAL or should I try another TV?

[pps]

therealbountybob, on Tue Nov 8, 2011 7:06 AM, said:

Hi,
on my (130xe) PAL CRT tv all the programs flickered; I didn't get the nice displays you have above - are the programs usable on PAL or should I try another TV?

The programme is best viewed with emulator altirra. There you can blend out the flickering. Real machines will have the flickering, while PAL ones will flicker more than NTSC ones. It´s the matter of all interlacing technics. But as seen in Space Harrier it is not a matter at all. For sure a textadventure would be very hard to read.

Edited by pps, Tue Nov 8, 2011 1:06 PM.

[Synthpopalooza]

The programs will flicker more if you are on a PAL machine. One thing that can help with this is using a monitor with a scan doubler. Also, when selecting your colors, watch your luminances, you don't want to vary the luminance between flickers by more than 4 steps, this will reduce the flicker in your designed character set.

There are also methods to use these character fonts in scanline mode (that is, changes are made per scanline). The limitations are, you can only do it in assembly, and it has to be a graphics mode which doesn't do display list swapping (this means you can't use DIN, or Super CIN/MIN/PCIN)

Also, if you are using Super IRG, Super 10, or the two PCIN modes based out of Antic 4, you can do a dithering pattern on your characters when using solid color fields. This is easiest to explain in Super IRG. The reason this works is because Super IRG and the other modes do not shift any of the color registers. Here's an example screenshot, first of the two font masks, then the resultant character:



Keep in mind that the cursor in this example is in the top left corner of the character grid.

If you will look at the palette bar (0-9 a-f) you will find some colors are identical. I call these "dithering pairs". In this case I am using colors 6 and 9 as my dithering pairs, these two colors are the result of blending PF0 and PF1, but on alternate frames. You will use one of the dithering pairs on alternate spaces on the grid, making a checkerboard pattern, filling in the spaces left with the other dithering pair color. This will reduce your flickering.

The method also works on Super 10, and on the PCIN (Gr. 12 + Gr. 10) modes, except that the pattern will be 2x8, and in PCIN you have to use 2 pixels on the Graphics 12 side of the display, paired with one pixel on the Graphics 10 side. Also, you can only do this with PF0-PF2 in this mode (or PF3 if you use Super PCIN) as these are the color registers shared between Graphics 12 and Graphics 10. I've included screenshot examples for Super PCIN:



In this example the dithering pairs are "7" and "A", these will blend PF1 and PF2 on alternate frames.

There is some striping in the character grid, because of the Graphics 10 pixel shift, but you will notice in the typing area this same character looks properly.

One feature I am considering for future versions is automatic color dithering in modes which support it. I know Bill Kendrick did this in his own SIFE Super IRG font editor.

Also, if you're trying to design readable text for a text adventure or a title screen, I've found that the DIN (gr.0 + gr.12) mode works best. You are blending pixels at a higher resolution (320 mixed with 160) and with careful color selection you can get a nice display. This is the mode I used for the ICE IRG Super Mario style title screen.

Edited by Synthpopalooza, Tue Nov 8, 2011 2:07 PM.

[Synthpopalooza]

There are more tips to reduce flicker.

If you are using HIP 0 or the MIN modes and using only monochrome values, you will also want to keep your luminances within a range of 4 when mixing. I think HIP 0 (like the bitmap version) lets you have 32 shades, while MIN reduces it to about 24, although your pictures will be less fuzzy.

You can also do dithering pairs in the MIN modes too. You need your PF0-PF3 settings to be 4-8-10-12 ... you get 5 level shading in Graphics 12 mixed with 16 level from Graphics 9. Intermixing with the even level shades in Graphics 9 creates the dithering pairs.

Here's an example of a solid color field in Super MIN, using dithering pairs:



Careful selection of colors is needed to create this effect. Remember to mix with even shades in Graphics 9 to do dithering on solid color fields. In theory you get 80 possible colors, but by limiting your lum difference by 4, it's closer to 24 shades, roughly.

Edited by Synthpopalooza, Tue Nov 8, 2011 6:48 PM.