ubiquitousse.asset

asset.lua

@@ -0,0 +1,72 @@
+-- ubiquitousse.asset
+
+-- The asset cache. Each cached asset is indexed with a string key "type.assetName".
+local cache = setmetatable({}, { __mode = "v" }) -- weak values
+
+--- Asset manager. Loads asset and cache them.
+-- This file has no dependicy to either ubiquitousse or a ubiquitousse backend.
+-- This only provides a streamlined way to handle asset, and doesn't handle the actual file loading/object creation itself; you are expected to provide your own asset loaders.
+-- See asset.load for more details. Hopefully this will allow you to use asset which are more game-specific than "image" or "audio".
+local asset
+asset = setmetatable({
+	--- A prefix for asset names
+	-- @impl ubiquitousse
+	prefix = "",
+
+	--- Load (and cache) an asset.
+	-- Asset name are similar to Lua module names (directory separator is the dot . and no extention should be specified).
+	-- To load an asset, ubiquitousse will, in this order:
+	-- * try to load the directory loader: a file named loader.lua in the same directory as the asset we are trying to load
+	-- * try to load the asset-specific loader: a file in the same directory and with the same name (except with the .lua extension) as the asset we are trying to load
+	-- Loaders are expected to return the new asset.
+	-- These loaders have acces to the following variables:
+	-- * directory: the asset directory (including prefix)
+	-- * name: the asset name (directory information removed)
+	-- * asset: the asset data. May be nil if this is the first loader to run.
+	-- @tparam assetName string the asset's full name
+	-- @return the asset
+	-- @impl ubiquitousse
+	load = function(assetName)
+		if not cache[assetName] then
+			-- Get directory and name
+			local path, name = assetName:match("^([^.]+)%.(.+)$")
+			if not path then
+				path, name = "", assetName
+			end
+			local dir = (asset.prefix..path):gsub("%.", "/")
+
+			-- Setup env
+			local oName, oAsset, oDirectory = name, asset, directory
+			name, asset, directory = name, nil, dir
+
+			-- Asset directory loader
+			local f = io.open(dir.."/loader.lua")
+			if f then
+				f:close()
+				asset = dofile(dir.."/loader.lua")
+			end
+
+			-- Asset specific loader
+			local f = io.open(dir.."/"..name..".lua")
+			if f then
+				f:close()
+				asset = dofile(dir.."/"..name..".lua")
+			end
+
+			-- Done
+			cache[assetName] = asset
+
+			-- Restore env
+			name, asset, directory = oName, oAsset, oDirectory
+		end
+
+		return cache[assetName]
+	end,
+}, {
+	--- asset(...) is a shortcut for asset.load(...)
+	__call = function(self, ...)
+		return asset.load(...)
+	end
+})
+
+return asset