Updated readme

README.md

@@ -146,3 +146,26 @@ ardugotools flashcart generate helpers/applysaves.lua myflashcart.bin newflashca
 ```
 
 Then you can flash `outflashcart.bin` to your Arduboy.
+
+#### Make Cart from folder
+
+If you don't want to write a script yourself to create a custom flashcart, you can instead
+set up a folder with all the categories and games and use `helpers/makecart.lua` to generate
+it for you. The folder must be setup in a certain way; see the comments in 
+[makecart.lua](helpers/makecart.lua) to get started. In general, you simply setup a folder
+where:
+- Each folder inside is a category
+- Each `.arduboy` package within the category folders are games in that category
+- You need a `title.png` at the root of the folder for the "bootloader" image
+- You need a `title.png` at the root of each category for the category image
+- Each package must have some image inside it to use as a title image. If it's missing
+  or if you want to override it, simply place a png file with the same name as the package
+  in the category directory next to the package.
+
+The arguments to pass in are the folder to read from, the devices to choose inside the 
+packages, and the path to save the flashcart binary to. An optional fourth parameter lets
+you indicate ignored folders by name, comma separated. Example:
+
+```
+ardugotools flashcart generate helpers/makecart mycart "Arduboy,ArduboyFX" flashcart.bin "ignore,trash"
+```

helpers/makecart.lua

@@ -105,11 +105,12 @@ for _, catinfo in ipairs(maindirlist) do
 		elseif string.sub(catfile.name, -8) == ".arduboy" then
 			-- This is a normal arduboy package
 			slot = packageany(catfile.path, devices)
-			if slot.image == nil then
-				-- Try to find an image with the same name as the package.
-				testimage = string.sub(catfile.name, 0, -8) .. "png"
-				log("Looking for alternate image in " .. testimage)
-				slot.image = load_title(catlist, testimage)
+			-- Try to find an image with the same name as the package.
+			local testimage = string.sub(catfile.name, 0, -8) .. "png"
+			local image = load_title(catlist, testimage)
+			if image ~= nil then
+				slot.image = image
+				log("Loaded alternate image in " .. testimage)
 			end
 			add_slot(slot)
 		elseif catfile.name ~= "title.png" then