8 replies to this topic

[Synthpopalooza]

Looks like I am at it again ... here's a test screen I did up ...




This is Graphics 1 using GTIA setting 128 (Graphics 10). I am using a font I designed originally for the Super IRG mode. What is happening here, is that the font is being changed every VBLANK, along with the screen memory. You have here a total of 9 color palettes, with the intermixing of 8 colors creating anywhere from 9-16 unique colors per palette. In total, 36 colors can be displayed. You have the first 64 characters of the character set available, as in normal Graphics 1.

How it works: You set up a Graphics 0 screen, change the lines to reflect ANTIC 6 (Graphics 1). This essentially creates memory for 2 Graphics 1 screens which will get interchanged every VBLANK. The method I use here is changing the screen memory in the display list.

Next, you reserve memory for a double 512K font (1024 bytes in total) and then shift CHBAS (756) every vblank.

It will be helpful to know how characters are displayed in Graphics 1.10 ... if you remember, graphics 1 uses only the first 64 characters in the character set, but the screen code determines the color (0-31 is PF0, 32-63 is PF1, 64-95 is PF2, and 96-127 is PF3). Graphics 1.10 is different. You get three palettes of 4x8 characters (which is like ANTIC 4/5) ... the palettes are laid out as such:

Screen code range: 00 01 10 11
0-31 704 704 704 704
32-65 704 705 708 709
66-95 704 706 712 712
96-127 704 707 708 711

when the high two bits of your screen code are 0, the character is completely blank. Otherwise, you have arrangements of between three and four colors per palette. The trick then, is to print the exact same character at the exact same location on both screens, but change the palette (i.e. print the same character from a different range). This gives you access to 9 unique palettes, with anywhere from 9 to 16 colors per palette. Some colors will be shared between palettes, but in total you can display 36 colors onscreen. This mode reminds me much of how graphics would be displayed on a Commodore 64 in low resolutions.

As a further explanation, here are the composite screens used to generate this display:




These are two seperate Graphics 1.10 screens which are being blended.

I have attached an ATR so you can see this for yourself. Other GTIA combinations are possible from this as well.

 super110.atr   90.02K   36 downloads

Edited by Synthpopalooza, Sat Aug 20, 2011 9:21 PM.

[Synthpopalooza]

This is APAC 1:




This time, GTIA is shifted from mode 9 to mode 11 along with the screen and CHBAS shift. This gives off 10 lum x 9 chroma plus the BG color, for 100 colors onscreen at once. Again, 9 unique palettes of 16 colors each in a 4x4 grid are used.

Here is the palette layout:

Screen code range: 00 01 10 11
0-31 0 0 0 0
32-65 0 1 4 5
66-95 0 2 8 10
96-127: 0 3 12 15


Again the lower range is undisplayable, so this leaves 3 palettes of 3 unique colors plus the background, which are again mixed amongst each other to create the 100 colors (4x4 per char).


Here are the composite screens:






ATR is here to see for yourself:


 apac1.atr   90.02K   28 downloads

[Synthpopalooza]

And now, HIP 1:




This is again in Graphics 1, but this time the GTIA is cycled from mode 9 to mode 10. In addition to the 80 colors which can be perceived onscreen at once, there is a pixel shift in graphics 10 which increases the apparent resolution to 160 pixels across. In essence, each character grid is 7 pixels wide with an artifact on either side of the grid.

Careful color register selection can produce 3 groups of color palettes, each one of three varying shades of brightness.

Here are the composite screens:




ATR is here:

 hip1.atr   90.02K   22 downloads

[Synthpopalooza]

Finally, CHIP 1:




This time, it is the GTIA being flipped from mode 10 to mode 11. As above, you get 80 colors, and the enhanced 160 pixel resolution. Here, I've chosen Graphics 10 color settings that augment the colors which are in the Graphics 1.11 palettes. This gives you 9 unique color palettes to choose from.

Composite screens:




And of course an .ATR

 chip1.atr   90.02K   27 downloads


My next project, of course, will be to do another ICE editor which can edit in these new character modes.

[Synthpopalooza]

Another one, this time CIN 1:




This is in Graphics 1, with the GTIA cycled between normal mode, and gr. 11

This time you get a full 8x8 character grid, but with 8 colors possible per char. In addition, you get 12 unique color palettes. The char layout is similar to my DIN (antic 2/antic 4) mode, and I reused a DIN font I had done inspired by the Robbo game, for this demo.

In total, 50 colors can be seen here at Graphics 1 resolution.

Composite screens:




And the .ATR (run CIN1.TUR)

 cin 1.atr   90.02K   45 downloads

[Stephen]

Synthpopalooza, on Sun Aug 21, 2011 11:35 AM, said:

Another one, this time CIN 1:

cin 1.png


This is in Graphics 1, with the GTIA cycled between normal mode, and gr. 11

This time you get a full 8x8 character grid, but with 8 colors possible per char. In addition, you get 12 unique color palettes. The char layout is similar to my DIN (antic 2/antic 4) mode, and I reused a DIN font I had done inspired by the Robbo game, for this demo.

In total, 50 colors can be seen here at Graphics 1 resolution.

Composite screens:

cin 1 (gr 1).png cin 1 (gr 11).png


And the .ATR (run CIN1.TUR)

cin 1.atr

Great work - much easier to visualize with the new graphics.

[Synthpopalooza]

This is PCIN 1:




Again in graphics 1, with GTIA being shifted between normal (0) and Graphics 10 (128) ... careful selection of color registers creates some subtle gradients on the numbers, plus the color registers of 708, 709, and 711 are common to both display modes, this also helps to reduce flicker. No color register shifting is done here at all, except for 712, which is the BG color in normal mode, but becomes a regular color in mode 10.

6-8 colors can be used per character cell, with 12 unique color palettes and 37 colors on screen at once. The font I used here is one I had used on my DIN (Antic 2/Antic 4) mode, as the character grid layout is the same (4x8 overlaid on 8x8).

There are 3-4 level gradients in the characters ... you will notice that the last 4 palettes feature only a 4 level gradient, this is because that Gr. 10 palette uses only 3 color registers ... BG + 711 + 712 + 712 ... the other two palettes have 4 color registers, however register 708 gets shared between those two.

You will notice the GR. 10 pixels are shifted to the right, this is due to the mode 10 color clock shift. A flip to HSCROL when the display is in normal mode, along with a custom display list, will correct this.

Here are the composite screens:




And here's the ATR ... run PCIN1.TUR

 pcin 1.atr   90.02K   27 downloads

Edited by Synthpopalooza, Mon Aug 22, 2011 10:39 PM.

[José Pereira]

There's no PCIN1.TUR there...

[Synthpopalooza]

ok, try this:

 pcin 1.atr   90.02K   30 downloads