GR. Text Modes and +16 and +32

[José Pereira]

Remembering ours old times begginers using Basic:

We have a 40Bytes wide screen X 192scanlines pre-defined screen.

If I write GR.12 I'll have a 20charlines of GR.12 and more 4charlines of GR.0 at the bottom (if I'll add +16 then it's all screen 24charlines in GR.12).

On GR.12 part I have BAK and PF0->PF3 and bottom GR.0 I have hi-res PF1 and PF2 colour registers. In the normal/pre-defined (no DLIs) screen the common PFs on the two gfxs modes (BAK, PF1 and PF2) have the same (colour,luminances) values?

I think they (at least PF1 and PF2) don't have because I remember that the bottom 'window' has the traditional A8 GR.0 blueish letters and 'paper' where the top has the normal green, pink,... 4colours PFs of the pre-defined GR.12 screen. This way it seems that the only that is the same is the BAK colour registes set to [00] black. Am I right?

 

Another question:

In this GR.12+GR.0 pre-defined it's one charset for the two or one for each?

 

 

For a text loading screen for a game (Assembly) if we set GR.12/ANTIC4 it doesn't work anymore the 320x192 pre-defined screen size and those pre-defined gfxs modes we have when working in Basic, right?

To have a loading screen that was supposed that they couldn't had DLIs then how, they turn that and have, for example, 3gfxs text modes in the International Karate screen showed during the loading process? And was the three gfxs just one or each of them it's one charset?

 

 

 

 

P.s.- And what if we add +32?

Edited November 13, 2013 by José Pereira

[Creature XL]

They have the same color values.

In your enumeration you forgot one color and that is "blue".

Its the same blue which is used at the "paper" color in the GR.0 part.

Just boot an emulator do the GR.-thing and then POKE 709,xx:POKE710,yy

 

 

I think it is only a slightly modified DL and nothing special.

 

Think about it, IF it would have been something special it would have been (ab)used by games and demos since years.

[Rybags]

Add +32 to the Graphics command means "don't clear the screen".

 

For the char + text window modes there's not 2 charsets, that would need a DLI. Also the GTIA modes don't allow text window.

 

The SuperMon OS IIRC allows the GTIA modes with a text window (using DLI) but that's very much a minority and not many use it.

 

For Assembler games, it's rare to use the OS anyway to setup your graphics modes. OK, you might get lazy and do the call for it to setup the initial screen/DList but it's madness to rely on it for doing much else.

 

For Basic games, it's fairly normal to use the OS to do much or all of the work. Fairly common also to alter a display list to your own needs. Also common to use short DLIs to do the stuff you decribed that normally can't be done, e.g. 2 charsets, different colours for each window, allow text under GTIA mode window etc.

[José Pereira]

So what they did in International karate to have the three text modes during loading?

Topo logo and bottom are in GR.1 and 2 and although same letters at different sizes these two modes are 64chars only.

(The top INTERNATIONAL KARATE blinking it's easy to understand as this Mode each 64x4 that is PF0->PF3 so it's just changing the char values or is it other?)

 

But then the middle part is in hi-res GR.0 that is a charmode that each charset has 128chars. They sure had to do DLIs to change between the charmodes.

[Rybags]

The screen with "INTERNATIONAL KARATE" in Gr. 2 then control stuff in Gr. 0 and "NOW LOADING" in Gr. 1 ?

 

Nothing really special going on there.

You don't need DLIs to change among graphics modes or character modes as long as GTIA mode stays the same (it does).

 

Gr. 1 and 2 allow 4 colours for text (PF0 thru PF3) - Gr. 0 has just 1 (PF1)

 

So, you can have the Gr. 0 window with static colours for PF1/PF2 and independant rotating colours in the Gr. 1 and 2 parts using PF0 and PF3.

[Creature XL]

Further , ther ei snothing special with DLIs during loading.

you just need to make sure they trigger.

The loading pic from MJO uses three charsets. And the two black lines do the DLI-magic.

It's a trick Stefan Dorndorf posted in the ABBUC forum.