mcl_banners, mcl_crafting_table: show banner crafting preview

A preview of a crafted banner is now shown next to the craft result box
to help players visualize what they're crafting. Due to the formspec
version, the preview can't be shown over top of the actual result slot.
A utility function (mcl_banners.get_overlay) is added to generate
formspec-able texture strings for arbitrary banners.

mods/ITEMS/mcl_banners/init.lua

@@ -144,6 +144,47 @@ local on_destruct_hanging_banner = function(pos)
 	return on_destruct_banner(pos, true)
 end
 
+local make_banner_overlay = function(base_color, layers)
+	local colorize = mcl_banners.colors[base_color][4]
+	-- Base texture with base color
+	local base = "(mcl_banners_item_base.png^(mcl_banners_item_overlay.png^[colorize:"..colorize..":"..base_color_ratio..")^[resize:32x32)"
+
+	-- Optional pattern layers
+	if layers then
+		local lovl = ""
+		for l=1, #layers do
+			local layerinfo = layers[l]
+			local pattern = "mcl_banners_" .. layerinfo.pattern .. ".png"
+			local color = mcl_banners.colors[layerinfo.color][4]
+
+			-- Generate layer texture
+			local layer = "(([combine:20x40:-2,-2="..pattern.."^[resize:16x24^[colorize:"..color..":"..layer_ratio..")^[mask:"..pattern..")"
+
+			lovl = (lovl ~= "" and (lovl .. "^") or "") .. layer
+		end
+
+		function escape(text)
+			 return text:gsub("%^", "\\%^"):gsub(":", "\\:") -- :gsub("%(", "\\%("):gsub("%)", "\\%)")
+		end
+
+		return "[combine:32x32:0,0=" .. escape(base) .. ":8,4=" .. escape(lovl)
+	end
+	return base
+end
+
+function mcl_banners.get_overlay(istk)
+	local imeta = istk:get_meta()
+	local layers_raw = imeta:get_string("layers")
+	if not layers_raw or layers_raw == "" then
+		return
+	end
+	local basec = istk:get_definition()._base_color
+	if not basec then
+		basec="unicolor_white"
+	end
+	return make_banner_overlay(basec, minetest.deserialize(layers_raw))
+end
+
 local make_banner_texture = function(base_color, layers)
 	local colorize
 	if mcl_banners.colors[base_color] then
@@ -420,6 +461,7 @@ for colorid, colortab in pairs(mcl_banners.colors) do
 		groups = groups,
 		stack_max = 16,
 
+		_base_color=colorid,
 		on_place = function(itemstack, placer, pointed_thing)
 			local above = pointed_thing.above
 			local under = pointed_thing.under

mods/ITEMS/mcl_crafting_table/init.lua

@@ -5,12 +5,14 @@ local C = minetest.colorize
 local text_color = mcl_colors.BLACK or "#313131"
 local itemslot_bg = mcl_formspec.get_itemslot_bg
 
-mcl_crafting_table = {}
-function mcl_crafting_table.show_crafting_form(player)
+mcl_crafting_table = {
+	last_table={}
+}
+function mcl_crafting_table.show_crafting_form(player, overlay)
 	player:get_inventory():set_width("craft", 3)
 	player:get_inventory():set_size("craft", 9)
 
-	show_formspec(player:get_player_name(), "main",
+	show_formspec(player:get_player_name(), "mcl_crafting_table:main",
 		"size[9,8.75]"..
 		"image[4.7,1.5;1.5,1;gui_crafting_arrow.png]"..
 		"label[0,4;"..formspec_escape(C(text_color, S("Inventory"))).."]".. --"#313131"
@@ -26,10 +28,31 @@ function mcl_crafting_table.show_crafting_form(player)
 		"image_button[0.75,1.5;1,1;craftguide_book.png;__mcl_craftguide;]"..
 		"tooltip[__mcl_craftguide;"..formspec_escape(S("Recipe book")).."]"..
 		"listring[current_player;main]"..
-		"listring[current_player;craft]"
+		"listring[current_player;craft]"..
+		(overlay and "image[7.1,1.5;1,1;"..formspec_escape(overlay).."]" or "")
+		 -- The overlay can be scooted back over top of the craftpreview once this formspec is
+		 -- updated to version 3.
 	)
 end
 
+if minetest.get_modpath("mcl_banners") then
+	minetest.register_craft_predict(function(itemstack, player, old_craft_grid, craft_inv)
+		if mcl_crafting_table.last_table[player:get_player_name()] then
+			local ovl=mcl_banners.get_overlay(itemstack)
+			mcl_crafting_table.show_crafting_form(player, ovl)
+		end
+	end)
+	minetest.register_on_player_receive_fields(function(player, formname, fields)
+		if formname ~= "mcl_crafting_table:main" then
+			return false
+		end
+		if fields["quit"] then
+			mcl_crafting_table.last_table[player:get_player_name()]=nil
+			minetest.close_formspec(player:get_player_name(), formname)
+		end
+	end)
+end
+
 local show_crafting_form = mcl_crafting_table.show_crafting_form  --cache function for better performances
 minetest.register_node("mcl_crafting_table:crafting_table", {
 	description = S("Crafting Table"),
@@ -43,6 +66,7 @@ minetest.register_node("mcl_crafting_table:crafting_table", {
 	paramtype2 = "facedir",
 	groups = {handy=1,axey=1, deco_block=1, material_wood=1,flammable=-1},
 	on_rightclick = function(pos, node, player, itemstack)
+		mcl_crafting_table.last_table[player:get_player_name()]=node
 		show_crafting_form(player)
 	end,
 	sounds = mcl_sounds.node_sound_wood_defaults(),

mods/ITEMS/mcl_crafting_table/mod.conf

@@ -1,3 +1,4 @@
 name = mcl_crafting_table
 description = Adds a crafting table.
 depends = mcl_init, mcl_formspec, mcl_sounds
+optional_depends = mcl_banners