Imposible Graphics mode

[Allas]

I'm curious about a demos I've seen.

 

First demo, show a aparently colofully screen, like a g2f technique. In bottom I see a Gr.9 merge with text build in Gr.8. Still I can solve how can be generated. No sprites.

 

http://atari.fandal.cz/detail.php?files_id=940

 

And this demos is very pretty. 3 different graphic modes with different colors in one scanline. How many times can be changed color registers in a scanline?

 

Nice sprites multiplexing... mmm...

 

http://atari.fandal.cz/detail.php?files_id=736

 

Anyone have a site with details from these techniques.

COMPUTE and MAPPING THE ATARI books has been overflowed

[Heaven/TQA]

re: 3 gr. modes

 

 

gtia/antic seem to have a bug... when switching in a scanline to gr.9 and then later back to gr.8 (i am not 100% sure about if it's gr.8...) antic/gtia stays in a gr.15-like mode instead of gr.8...

[Allas]

In newsgroup a guy explain some of the programing. In his words:

 

The trick used by Our5oft is very simple:  

 

 

1) we are waiting for desired scanline  

2) then we use some NOP's as delay into scanline  

3) we are swichting on the GR.9 using GTIACTL (called GPRIOR) register  

4) then we use some NOP's again  

5) then we are switching GTIA back to the GR.8 (in the same scanline)  

 

The GTIA-chip becomes "stupid" and produces GR.15.

[Allas]

I found these demos from COLORVIEW utility APAC system graphic. 4096 colors for 8bit. Wow..!!!

 

Only flick a little, but really shows good graphics. I never see a game or presentation that use this type of graphics.

 

 

Use 3 screens in Gr.9 (Red, Blue, Green), and mixing the image create a image in 16*16*16=4046 colors in 80x192

 

Something similar can do it but with gr.15 screens. We can get 4*4*4=64 colors. Just nice graphic for a game presentation.

[emkay]

And this demos is very pretty. 3 different graphic modes with different colors in one scanline. How many times can be changed color registers in a scanline?

 

http://www.atariage.com/forums/viewtopic.p...highlight=clues

 

 

Having a look at my Game, that I finished in 1991, plus the Nazgul Demo, you might see quite the difference:

 

While the Demo still shows some enhanced features, I prefer to bind those features into programs, to enhance the functionality.

In Admirandus the triple Gr.-Mode is used to enhance the information on one screen.

In Nazgul, the overlay ehances the Information, because the scrolling over the Image...

 

BTW: Did you recognize the "Hires Color Font" in Admirandus?

[emkay]

 

.....that I finished in 1991......

 

Typo

 

It's 1990 ofcourse

[Bryan]

re: 3 gr.  modes

 

 

gtia/antic seem to have a bug... when switching in a scanline to gr.9 and then later back to gr.8 (i am not 100% sure about if it's gr.8...) antic/gtia stays in a gr.15-like mode instead of gr.8...

 

Right. During a line, you cannot switch back to high rez from a GTIA mode. Instead it produces a 160 mode.

 

-Bry

[analmux]

I'm curious about a demos I've seen.

 

First demo, show a aparently colofully screen, like a g2f technique. In bottom I see a Gr.9 merge with text build in Gr.8. Still I can solve how can be generated.  No sprites.

 

http://atari.fandal.cz/detail.php?files_id=940

 

What do you mean with "no sprites"?. I think the 4 darkblue bars are missiles with 5th color and the 2 gradient bars are players with ORed palettes. each gradient bar consisting of 2 players.

 

Note that there are really 5 different lumas for the background:

444442468A8642468A86424444444244444

...or something:

[Allas]

What do you mean with "no sprites"?. I think the 4 darkblue bars are missiles with 5th color and the 2 gradient bars are players with ORed palettes. each gradient bar consisting of 2 players.

 

Note that there are really 5 different lumas for the background:

444442468A8642468A86424444444244444

...or something:

 

I can't explain myself how I am deceived, but it was