It’s possible edit default palette for bitmap in Atari?

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  • #1035
    retrokikems
    Participant

    The actual palette for use with Atari bitmaps result too dark for some graphics. It’s possible define other palette colors for 16c bitmaps and gimp Atari palette? and if it’s possible , how to edit?

    #1039
    8bit-Dude
    Keymaster

    The 16 colors are obtained by mixing 4 basic colors (black, red, green, blue).
    If you want to make these colors brighter, check the function ShowBitmap().
    It calls a sub-function “SetPalette(bmpPalette);”

    The 4 values of bmpPalette correspond to the first 4 bytes of the image file loaded in LoadBitmap().
    You can either hack ShowBitmap to edit the values in the bmpPalette array, of modify the python conversion script to write different values for these 4 bytes.

    (see: https://github.com/8bit-Dude/8bit-Unity/blob/main/docs/Palettes/ATARI-Sprites.png)

    • This reply was modified 1 year, 5 months ago by 8bit-Dude.
    #1042
    retrokikems
    Participant

    Great, I’ll try it.

    #1043
    retrokikems
    Participant

    You have the formula or method to predict what intermediate colors can obtain when change the 4 basic colors?

    • This reply was modified 1 year, 5 months ago by retrokikems.
    #1045
    8bit-Dude
    Keymaster

    It will be basically the average of both colors… To simulate, you can take the RGB values of the 2 colors in the Atari palette I referenced above, then average them. Doing this for each combination, you can rebuild a new palette in GIMP…
    (You can also easily display the new palette by running the demo disk, then use the color pick tool in gimp to retrieve the RGB value of each color)

    • This reply was modified 1 year, 5 months ago by 8bit-Dude.
    #1063
    retrokikems
    Participant

    It works, thanks. If palette can be defined and different for every bitmap image in the main code of game will be great, it’s very usefull in some games like goblins with lot of different background graphics.
    Your new DLI routine of github works really good, not flickering on Atari now.

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