Aesprite Procedural Generation Tilemap Builder

export_procedural_aesprite_tilemap.lua

--[[
@title: Aesprite Procedural Generation Tilemap Builder
@author: nftchance
@note: This was written in mind off on-chain (blockchain) pixel art however this is not just limited to the utilization of blockchain needs. This is an incredibly efficient workflow for all "procedural generation" populations.
@license: MIT

@installation: to use this script you need to import this script into your Aesprite scripts folder.

This script is utilized within the pixel art tool, Aesprite (https://www.aseprite.org/). The tool is incredibly easy to use and what most on-chain artists should realistically be using due to the workflow that can be created. The quality of art and workflow are significantly improved. However, with character-heavy art it is vital that you can export each individual layer tilemap and the pieces that are contained within that. This scripts solves that problem.

1. To use this script all you have to do is create your individual layers as Tilemaps as you will need each piece for your generation system (whether it is on-chain or not)
2. Select the script
3. Select the tilemaps to export
4. Relax as the script handles all tiling and creation of your tile-ready assets
5. Straight to action no more time wasted messing with art massaging

@returns: segmented assets of pixel project
]]--

local spr = app.activeSprite
if not spr then return print "CHOOSE AN ACTIVE SPRITE MFER" end

local fs = app.fs

-- save all images into the asset folder
local output_folder = fs.filePath(spr.filename) .. "/assets"

local dlg = Dialog('EXPORT TILEMAP')

-- function that runs the actual processing of splitting and saving tiles
local function exportTileset(tileset, name, n, padding)
    local grid = tileset.grid
    local size = grid.tileSize

    if #tileset > 0 then
        -- bark the orders of the image we need
        local spec = spr.spec
        spec.width = size.width + (padding * 2)
        spec.height = ((size.height + (padding * 2) - padding) * #tileset) + padding

        -- if we are using pieces we need one the dimensions to be one tile
        if dlg.data.pieces then
            spec.height = size.height + (padding * 2)
        end

        -- create the actual image object
        local image = Image(spec)
        image:clear()

        -- default filename is a collective tileset image
        local imageFilename = fs.joinPath(
            output_folder .. "/" ..name, 
            name .. ".png"
        )

        -- todo: is it an issue that we aren't increasing i ?

        for i = 0, #tileset - 1 do
            local tile = tileset:getTile(i)

            -- if we are reusing the same object we need to clear it
            local tilePadding = padding + ((i * size.height) + (i * padding))

            if dlg.data.pieces then
                image:clear()
                tilePadding = padding
                imageFilename = fs.joinPath(
                    output_folder .. "/" .. name, 
                    i .. ".png"
                )
            end

            -- actually draw the tile
            image:drawImage(
                tile,           -- tile to draw
                padding,        -- horizontal padding
                tilePadding     -- vertical padding
            )

            -- save the piece if we are using pieces
            if dlg.data.pieces then
                image:saveAs(imageFilename)
            end
        end

        -- save the collective image if we haven't yet (overwrites the last piece of pieces is enabled but that is fine)
        image:saveAs(imageFilename)

        -- open the image (or last image if pieces is enabled)
        if dlg.data.openFiles then
            app.open(imageFilename)
        end
    end
end

-- function that handles which tiles to generate based on the dialog
local function startExport()
    local data = dlg.data
    local n = 0

    for _, layer in ipairs(spr.layers) do
        if layer.isTilemap then
            n = n + 1 -- note: i have no idea why we must pre-incremente here
            if data["tileset" .. n] then
                exportTileset(
                    layer.tileset, 
                    layer.name, 
                    n, 
                    data.padding
                )
            end
        end
    end

    dlg:close()
end

-- function that adds the tilemap options that can be chosen to the dialog
local function addTilemapOptions()
    local n = 0
    for _, layer in ipairs(spr.layers) do
        if layer.isTilemap then
            n = n + 1
            dlg:check{ id = "tileset" .. n, text = layer.name, selected=true }
        end
    end
end

-- building the actual dialog (inline script)
dlg:check{ id = "pieces", text = "PIECES", selected=true }
dlg:check{ id = "openFiles", text = "OPEN FILES ON GEN.", selected=false }
dlg:number{ id = "padding", label = "PADDING: ", text = "16" }

addTilemapOptions()

dlg:button{ text = "&CANCEL", onclick=function() dlg:close() end }
dlg:button{ text = "&START", onclick=function() startExport() end }

dlg:show{ wait = false }