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Irgendwer

Move along folks, nothing to see here!

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Hi,

as some may know, I played quite a while with the A8 graphics modes to achieve unexpected output (like http://atariage.com/forums/topic/124933-new-true-color-mode/#entry1510330 or http://atariage.com/forums/topic/134852-atari-v-commodore/page-220#entry1737525).

 

I never liked interlace or the scan line grille of APAC, so since several years I tried to cope with the restrictions and tried various things. Finally I have a result which I find convincing.

The format is nothing really new, just works like HIP without interlace and can be coloured (the profile image of member 'pirx' seems to use this principle already), but I created a converter which is very easy to use, and at least I'm not aware of a similar one. Since I haven't found any description of this format in conjunction with a name, I named it 'JAG' (Just Another Graphics-(format)).

 

The creation process is half automatic and a conversion takes about two dozens of clicks (colour assignments), which can be performed in a minute.

(I had a fully automatic process, but results are less convincing.)

 

When compared to RastaConverter (BIG LIKE!), the only disadvantages are the lower resolution and on NTSC systems the images are not that colourful, but the advantages are:

 

* CO2 friendly: conversion is question of minutes ;)

* no affinity to banding (but depending on mode/selection slightly scan line grille)

* no use of PMGs (less memory and DMA load) (and usable in game scenarios (even with limited colour possibilities)

* simple to save & load

* simple code for depiction

* ATM moderate DLI load: converter supports a single palette for the complete image (this is subject to change, which can improve output quality a lot - depending on the input image)

* easier to use in animation scenarios (generation is more 'stable', since available colours can be distributed more freely)

* more shades (currently only the obvious theoretical 144 (9*16) per image, in the future all 256)

 

There are still bugs in the converter I need to fix (some are detectable in the images below), output has to be beautified (e.g. top colour border) and I have to write some instructions too, but hopefully next week I can release V1 (if there is demand?).

 

Have fun and stay tuned...

 

 

post-7778-0-97386200-1414365399_thumb.png

post-7778-0-16402200-1414365401_thumb.png

post-7778-0-03339100-1414365402_thumb.png

post-7778-0-29504900-1414365403_thumb.png

post-7778-0-30080200-1414365404_thumb.png

post-7778-0-31826800-1414365405_thumb.png

post-7778-0-23480900-1414365406_thumb.png

post-7778-0-17157100-1414365407_thumb.png

post-7778-0-05942900-1414365408_thumb.png

Edited by Irgendwer
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Holy $hit that's awesome. In a total bit of co-incidence (or universal randomness, of which I am believing in less and less as time goes by), I am listening to Tubular Bells on vinyl this evening with the gf :)

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Thanks, I forgot a very important one ;-) :

 

 

Wow! Finally there's a version of Centron that runs on the A8! And without all that annoying gameplay!
Edited by Bryan
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Irgendwer, the sample pictures seem quite colorful on my NTSC TV, although the palette is shifted a tiny bit.

 

Thanks for this and all your efforts!

Edited by a8isa1

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Very good.

Some of the images also have better details than the Rastaconverter, because of the linearity, that the image is stored with.

 

Particular

 

-Venus

-Tubular Bells

-Tiger

-Mandrill

-Frog

-Doblo

-Astronaut

 

Thinking about the fact that PMG is still unused...

Edited by emkay

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BTW - you can nicely hide jaggy (pun intended) borders under 2 black missiles. It improves the effect greatly.

 

Hmm - are you sure? Contrary to Gr.10 where COLBK forms the background color and has to be black for all 16 shades, in GR.10 the background color is COLPM0. So even when using one Player and the associated Missile to be black and hide the border grille your loosing one color for depiction.

 

IMHO there are two solutions (both reduce performance):

* use overscan (currently no problem with DMA load) and fill the border area with COLBK pixels on GR.10 lines

* switch COLBK and COLPM0 colors in DLI for every scan-line (would work now too, but reduces color changing possibilities for improved reproduction in the future...)

 

For those cases where the DMA/DLI-load is already critical, applying the second darkest color to COLPM0 seems a feasible solution to me.

 

 

Wow, those look fantastic! I love the photo of the Atari 800. :) Would be interesting to see animations or games using this technique!

 

Yep - thought so too. I will try out animations later on for sure. Thinking about doing the 'Rose to Skull' sequence of Myst (http://www.youtube.com/watch?feature=player_detailpage&v=Bx0dvZhzwP0#t=133), and porting later the complete game... :lol:

 

 

Thinking about the fact that PMG is still unused...

 

Since the color registers are all in use PMGs should be used with care or interesting things could be added utilizing GPRIOR... (have to check that later too)

 

Thank you all for the applaud!

Edited by Irgendwer

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Hmm - are you sure? Contrary to Gr.10 where COLBK forms the background color and has to be black for all 16 shades, in GR.10 the background color is COLPM0. So even when using one Player and the associated Missile to be black and hide the border grille your loosing one color for depiction

 

How about setting PRIOR[3:0] to 1111 and enabling 5th player so that missiles will be rendered as black regardless of COLPF3? See also Chapter 6, Table 5 in the Altirra Harware Reference Manual.

 

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Black borders proof of concept:

 

jagborder.xex

post-21021-0-96362500-1414532037_thumb.png

 

I just added the following code to your executable:

 

    mva #$29 HPOSP3
    sta HPOSM1
    mva #$CF HPOSP2
    sta HPOSM0
    mva #$9F $2047
    sta $2011
    mva #$FC GRACTL
    mva #$FF GRAFM
    sta GRAFP2
    sta GRAFP3
    sta SIZEM

The basic concept is that a player over 5th player yields black.

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Hey, you can do this with missiles only - here's code from my intro above:

    ;vertical blinds (missiles)
    lda #$30
    ldx #28 ;blinds start
    sta PMG+$300-1,x
    lda #$FF
PMGblinds
    sta PMG+$300,x
    inx
    cpx #189  ;blinds end
    bne PMGblinds
    
    mva #41 HPOSM0
    mva #41-8 HPOSM3
    mva #208 HPOSM1
    mva #216 HPOSM2

    mva #$ff  SIZEM
    mva #>PMG PMBASE
    mva #3 PMCNTL
    mva #%00000001 SIZEP0
    
    lda #%00111110
    sta dmactls 

and also in DLI:

GTIACTLBITS = %010110
    lda #$80+GTIACTLBITS 
    sta WSYNC
    sta GTIACTL   

and so on.

 

Best,

 

pirx

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Some refinements:

jagborder-wider.xex
post-21021-0-77507700-1414535915_thumb.png

  • Wider right and left borders
  • Black top border

Source on github.

 

Pirx, the reason missiles alone don't work here is because Irgendwer is not setting COLPM0 or COLPF3 to black. Maybe if he reorganized his color settings it would work like that.

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Pirx, the reason missiles alone don't work here is because Irgendwer is not setting COLPM0 or COLPF3 to black. Maybe if he reorganized his color settings it would work like that.

 

Thank you all for the hints. I enjoy the momentum very much.

You are right, there is no black in PMx, because I don't like to switch black from BK to PM0 to save the cycles for further features. There is no point using PMGs when PM0 is black anyway (?), since then the fringes wouldn't appear...

Using GRAFM instead of PMG-DMA is also a plus.

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Thank you all for the hints. I enjoy the momentum very much.

It's very cool indeed. I'd like to try some animations at some point. Looking forward to your converter.

There is no point using PMGs when PM0 is black anyway (?), since then the fringes wouldn't appear...

 

True, the borders won't alternate between black and colored lines, but you'll still have a jagged edge due to the offset of 9-color mode. In both cases, PMGs can provide a nice straight border.

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