Radastanian graphics

[SamC]

not much used, although pretty cute and "economical", it consists of 6144 (6160) bytes in zx screen area

it doesn't seem to be supported anymore, several games exist
especially the Return to Holy Tower is a great game
https://www.zxuno.com/ht2/

here are some screens:
https://zxfiles.samcoupe.cz/download/mb03/RADASHOW.TAP



10 REM activate radastanian mode
20 OUT 64571,64: OUT 64827,3
30 REM Load screen and palette (6144 + 16 bytes)
40 LOAD "" CODE 16384
50 REM set palette
60 FOR p = 0 TO 15: OUT 48955, p: OUT 65339, PEEK(p + 22528): NEXT p
70 PAUSE 0
80 REM deactivate radastanian mode
90 OUT 64571,64: OUT 64827,0

Radastan Mode is available on: ZX-Uno family (ZXDOS+ etc.), SpecNext, MB03+ interface, ZX eLeMeNt
More demos and support available?

[bob_fossil]

I created a couple of screens (as well as converting the included ones from the ZX-UNO distribution) and included them in the media package for my long filename browser which supports displaying them as .RAD files. These are 6262 bytes long as they are in windows .bmp format.

[SamC]

These are 6262 bytes long as they are in windows .bmp format.

thanks, I was not aware of the length of that format

I used this converter: https://github.com/Utodev/radascreen
which can produce files of 6160 bytes
a raw binary, in which a colour palette is stored right behind the pixel bitmap

such a SCR files are in the esxDOS TAR archive, RADASHOW.TAR
on the page https://zxfiles.samcoupe.cz/zxmb03.php

[bob_fossil]

I used this converter: https://github.com/Utodev/radascreen
which can produce files of 6160 bytes
a raw binary, in which a colour palette is stored right behind the pixel bitmap

I wasn't aware of this variant of the format, so I'll add it to my plugin.

The Radastan .tap files included with the ZX-UNO were in this BMP format. This format makes it easy to create new screens as you can use an image package like GIMP to resize your source picture to 128 x 96 pixels, reduce it to 16 colours and save it as a BMP without colourspace information - which gives you a 6262 byte file..

[SamC]

ah, BMPs direct suppport, I could save time ...
in that case, a converter is not needed

[Alone Coder]

Where are the sources of Return to Holy Tower, to port it to something except FPGA?

[Alcoholics Anonymous]

The example program isn't enabling ula+ so needs a few more outs:

10 REM activate radastanian mode
20 OUT 64571,64: OUT 64827,3
25 OUT 48955,64: OUT 65339,1
30 REM Load screen and palette (6144 + 16 bytes)
40 LOAD "" CODE 16384
50 REM set palette
60 FOR p = 0 TO 15: OUT 48955, p: OUT 65339, PEEK(p + 22528): NEXT p
70 PAUSE 0
80 REM deactivate radastanian mode
90 OUT 64571,64: OUT 64827,0
95 OUT 48955,64: OUT 65339,0

On a zx next, radastan mode is enabled differently so lines 20 and 90 need to be replaced with:

20 REG 106,32: REG 21,128
90 REG 21,0

The lores mode in the Next comes in two colour resolutions: 128x64x8 and 128x64x4 (radastan). The REG to 106 chooses radastan. The REG to 21 enables lores mode.

From nextbasic or esxdos you can mount the tap file to load screens with:

.tapein radashow.tap

The next requires a further:

load "t:"

to redirect file loading from sd card to audio tape (the tapein redirects audio tape to tap file).

I stumbled across the thread and wanted to see if it worked

[SamC]

The example program isn't enabling ula+ so needs a few more outs:

Really? I did not know about this fact.
The ULA+ palette seems to be an inherent part of the Radastan, simply said: some ULA+ palette is always used.

(?) Commands OUT 48955,64 and OUT 65339,1 should have different purpose,
should switch into and allow to change a colour palette...

If you are right, also this dot-cmd should be improved... https://board.esxdos.org/viewtopic.php?id=1041

Any detailed technical info about these ZX-Uno features?

[bob_fossil]

You don't need to enable ULA+ on the ZX-UNO for Radistan mode. I'm not doing this in the RAD plugin for my browser and Radistan mode works. You just need to do:

OUT 64571,64: OUT 64827,3

From the ZX-UNO manual (September 2016)

Code: Select all

Activating Radastan mode

The Radastan mode is for the time being exclusive to ZX-Uno. It is a low resolution mode
that doesn't have attribute clash. To activate radastan mode, using the RADASCTRL ZX-Uno
register is needed (0x40, or 64). This is the sequence to activate it:

OUT 64571,64
OUT 64827,3

To go back to the previous mode, the second OUT value should be 0.

Note: the first version of the ZX Spectrum core used another method using the ULAPlus
register. To avoid future incompatibilities that method has been removed.

[Alcoholics Anonymous]

(?) Commands OUT 48955,64 and OUT 65339,1 should have different purpose,
should switch into and allow to change a colour palette...

No that will turn on ula+. The mode register is selected, bit 0 controls whether ula+ is on or off.
https://zxdesign.itch.io/ulaplus

The ULA+ palette seems to be an inherent part of the Radastan, simply said: some ULA+ palette is always used.

You (and bob) are very likely right. There is no other sensible way to generate colours from 4-bit pixels so it makes sense that the uno would automatically feed pixels through the ula+ palette.

So this would be a Next only thing. The Next has a bigger palette (256 entries) of which ula+ (64 entries) is a subset so there is no need to use ula+ by default nor would you want to.

On the Next, radastan was almost an afterthought as we thought it would be a good idea to have some compatibility there. The lores mode started at 128x96x8 because the Next palette is 256 entries. When radastan was added, I found it very hard to find good information on how it worked in particular in how the palette shifts happen -- the 4-bit pixels use 16 entries of the 64 entry ula+ palette but you can apparently shift which 16 entries in the ula+ palette gets used.

So as radastan (4-bit pixels) is mainly there because of the uno, I think I will add it to the to-do to make the Next more compatible with the uno for radastan mode specifically. The scrolling capability I'd have to think about as the Next has pixel scrolling on all layers implemented in one way; the radastan scrolling is built on varying the base address of the radastan screen I believe.

Edit: Yes, the information is out there now. https://www.zxuno.com/wiki/index.php/ZX ... _de_ZX-Uno

[SamC]

Mandelbrot

https://zxfiles.samcoupe.cz/download/mb03/RADAMAND.TAP

https://www.youtube.com/watch?v=8Wr23-uKA70

[bob_fossil]

Nice! Draws much quicker at 28mhz.

[SamC]

The RAD (or RDS) screen format is now supported in the DaDither convertor (you must go to the eLeMeNt ZX section).

Several old pieces of Radastanian software found: Movie Player and HW Scroll demonstrations, T-Rex... https://zxfiles.net/zxmb03.php#gfx