devkitPro

Posted: **Thu Jul 04, 2019 9:23 pm**

Hello everyone,
I'm a new developer on nintendo ds and I'm trying to build some simple examples to test the feature of the nintendo ds. In the quest doing this I marched upon Extended Palettes which seem to be new compared to the gba. If I understand correctly the idea is that you can sacrifice some ram to have a maximum of 16*256 colors per background instead of juste 256 for the main or the sub and would hence allows for much richer graphics.

So I tried to setup the extended palette in the same fashion that the exemples at https://github.com/devkitPro/nds-exampl ... ackgrounds, (I noted that I had to set the while loop to true to work on desmume for some reason even if it works on the ds). So far so good now the problem is I wanted to use the extended palette with some tiled graphics.More specifically a tiled background on the sub engine bg 2 with tiles and palette generated by grit and a custom map and also a bg 1 with text that would be mapped manually from tiles and palette generated with grit too.
I could achieve to have both backgrounds displayed but I still have a minor problem because my text background is not transparent. So I was wondering if this is expected with extended palettes or not.
Here are some of the relevant calls that summarize what I have done:

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   bgExtPaletteEnableSub();

    vramSetBankC(VRAM_C_SUB_BG);
    videoSetModeSub(MODE_0_2D);
    int bg1Sub = bgInit(1, BgType_Text8bpp, BgSize_T_256x256, 1, 2);
    int bg2Sub = bgInit(2, BgType_Text8bpp, BgSize_T_256x256, 1, 0);

    dmaCopy(menuButtonTiles, (void *)bgGetGfxPtr(bg2Sub), menuButtonTilesLen);

    vramSetBankH(VRAM_H_LCD); // for sub engine

    dmaCopy(menuButtonPal, (void *)&VRAM_H_EXT_PALETTE[bg2Sub - 4][0], menuButtonPalLen);

    vramSetBankH(VRAM_H_SUB_BG_EXT_PALETTE); // for sub engine

    dmaCopy(backgroundTextMap, (void *)bgGetMapPtr(bg2Sub), backgroundTextMapLen);    

    dmaCopy(ocrFontTiles, bgGetGfxPtr(bg1Sub), ocrFontTilesLen);

    vramSetBankH(VRAM_H_LCD); // for sub engine
    dmaCopy(ocrFontPal, &VRAM_H_EXT_PALETTE[bg1Sub - 4][0], ocrFontPalLen);
    vramSetBankH(VRAM_H_SUB_BG_EXT_PALETTE);

    // setting map manually with bgGetMapPtr(bg1Sub)[pos] = ...

I set the grit like this for the bg2:

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-g -gt -gB8 -p -m -mR8 -gTFF00FF

And for the text

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-g -gt -gB8 -p -m! -mR! -gTFF00FF

both images use the correct color 0xFF00FF as transparnet background color

And the result is the following one :

Screenshot 2019-07-04 at 22.20.40.png: (206.9 KiB) Not downloaded yet

Thx for reading and if anyone has an idea where this come from or could explain me the limitations of extended palettes it would be great!

Posted: **Fri Jul 05, 2019 3:47 pm**

It's been a while since most of us dealt with DS code so please bear with us.

The first thing that pops out is that the first dimension on the *_EXT_PALETTE array is the hardware background number. The return value from bgInit is an internal id & not related to hw background. You should use the hardware background number you asked for in the bgInit call in this code.

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 dmaCopy(menuButtonPal, (void *)&VRAM_H_EXT_PALETTE[bg2Sub - 4][0], menuButtonPalLen);

i.e. 2, not bg2Sub -4.

I'll need to dig through some code to check if the -gT parameter works as expected here - iirc it was definitely supposed to. It would help a lot if you provided your code & source images for us to check what's actually happening.

Posted: **Sun Jul 07, 2019 7:00 pm**

Hi, and first of all thx for the response!
Thx to your note I finally found out what was wrong not directly but looking at how I generated my backgrounds, I was simply not giving enough space to my tiles in the vram (some wrong map_base, tile_base combination)! Everything's working like a charm now!

But while I'm at it I have another question regarding grit, I just can't figure out how I should give the parameters to make a shared palette from multiple png's. For example if I have a.png , b.png and c.png and I would like to generate the tiles for each one, no map (because I'll use it for sprites) and a shared palette for all of them.
Probably using the template makefile can't handle such case for grit no? I tried then to generate it manually using:

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grit a.png b.png c.png -W3 -g -gt -gB8 -Mh4 -Mw4 -m! -p -pS -S a.s b.s c.s -O abc

But this doesn't seem to work.
Any clue on how to use the -pS option correctly?
Best,
Philippe

devkitPro

Extended Palettes and Transparency

Extended Palettes and Transparency

Re: Extended Palettes and Transparency

Re: Extended Palettes and Transparency