Aseprite Lua script to export for memory.undertale.com

aseprite-undertale-memory-index.lua

local sprite = app.activeSprite

-- Check constraints
if sprite == nil then
    app.alert("No Sprite...")
    return
end
if sprite.colorMode ~= ColorMode.INDEXED then
    app.alert("Sprite needs to be indexed")
    return
end

local idxToColorName = {
    [0] = '0',
    [1] = '1',
    [2] = 'r',
    [3] = 'o',
    [4] = 'y',
    [5] = 'g',
    [6] = 'b',
    [7] = 't',
    [8] = 'p',
    [9] = '0'
};

local function getIndexData(img, w, h)
    local res = ""
    for y = 0, h - 1 do
        for x = 0, w - 1 do
            local px = img:getPixel(x, y)
            local colorName = idxToColorName[px];
            res = res .. string.format("%s", colorName)
        end
        -- res = res .. "\n"
    end

    return res
end

local function exportFrame(frm)
    if frm == nil then frm = 1 end

    local img = Image(sprite.spec)
    img:drawSprite(sprite, frm)

    io.write("Palette Indexed Picture\n")
    io.write(getIndexData(img, sprite.width, sprite.height))
end

local dlg = Dialog()
dlg:file{
    id = "exportFile",
    label = "File",
    title = "Undertale Memory Index Exporter",
    open = false,
    save = true,
    filetypes = {"txt"}
}
dlg:check{
    id = "onlyCurrentFrame",
    text = "Export only current frame",
    selected = true
}

dlg:button{id = "ok", text = "OK"}
dlg:button{id = "cancel", text = "Cancel"}
dlg:show()
local data = dlg.data
if data.ok then
    local f = io.open(data.exportFile, "w")
    io.output(f)

    if data.onlyCurrentFrame then
        exportFrame(app.activeFrame)
    else
        for i = 1, #sprite.frames do
            io.write(string.format(";Frame %d\n", i))
            exportFrame(i)
        end
    end

    io.close(f)
end

Note that it assumes you have a palette set up in Aseprite with the following Index -> color mapping:
0 -> black
1 -> white
2- > red (ff0000)
3-> orange (fca600)
4 -> yellow (ffff00)
5 -> green (00c000)
6 -> blue (003cff)
7 -> light blue (42cff0)
8 -> purple (d535d9)
9 -> transparent