create proper stairs mod replacement; create option to allow registering stairs w/out a proper recipeitem

stairs/util.lua

@@ -0,0 +1,47 @@
+local default_align_style = stairsplus.settings.default_align_style
+
+local util = {}
+
+-- get node settings to use for stairs
+function util.get_node_vars(nodename)
+	local def = minetest.registered_nodes[nodename]
+
+	if def then
+		return def.light_source, def.use_texture_alpha, def.sunlight_propagates
+	end
+end
+
+function util.get_stair_images(images, worldaligntex)
+	local stair_images = {}
+
+	for i, image in ipairs(images) do
+		local stair_image
+
+		if type(image) == "string" then
+			stair_image = {
+				name = image,
+				backface_culling = true,
+			}
+
+		else
+			stair_image = table.copy(image)
+			if stair_image.backface_culling == nil then
+				stair_image.backface_culling = true
+			end
+		end
+
+		if stair_image.align_style == nil then
+			if worldaligntex then
+				stair_image.align_style = "world"
+			else
+				stair_image.align_style = default_align_style
+			end
+		end
+
+		stair_images[i] = stair_image
+	end
+
+	return stair_images
+end
+
+stairs.util = util