Allow groups in crafting recipes

doc/lua_api.txt

@@ -363,8 +363,7 @@ effective towards.
 
 Groups in crafting recipes
 ---------------------------
-- Not implemented yet. (TODO)
+An example:
-- Will probably look like this:
 {
     output = 'food:meat_soup_raw',
     recipe = {
@@ -372,7 +371,7 @@ Groups in crafting recipes
         {'group:water'},
         {'group:bowl'},
     },
-    preserve = {'group:bowl'},
+    preserve = {'group:bowl'}, -- Not implemented yet (TODO)
 }
 
 Special groups
@@ -1210,19 +1209,19 @@ Node definition (register_node)
     ^ default: minetest.node_metadata_inventory_take_allow_all
 }
 
-Recipe: (register_craft)
+Recipe for register_craft: (shaped)
 {
     output = 'default:pick_stone',
     recipe = {
         {'default:cobble', 'default:cobble', 'default:cobble'},
         {'', 'default:stick', ''},
-        {'', 'default:stick', ''},
+        {'', 'default:stick', ''}, -- Also groups; eg. 'group:crumbly'
     },
     replacements = <optional list of item pairs,
                     replace one input item with another item on crafting>
 }
 
-Recipe (shapeless):
+Recipe for register_craft (shapeless)
 {
     type = "shapeless",
     output = 'mushrooms:mushroom_stew',
@@ -1235,13 +1234,13 @@ Recipe (shapeless):
                     replace one input item with another item on crafting>
 }
 
-Recipe (tool repair):
+Recipe for register_craft (tool repair)
 {
     type = "toolrepair",
     additional_wear = -0.02,
 }
 
-Recipe (cooking):
+Recipe for register_craft (cooking)
 {
     type = "cooking",
     output = "default:glass",
@@ -1249,7 +1248,7 @@ Recipe (cooking):
     cooktime = 3,
 }
 
-Recipe (furnace fuel):
+Recipe for register_craft (furnace fuel)
 {
     type = "fuel",
     recipe = "default:leaves",

games/minimal/mods/experimental/init.lua

@@ -496,6 +496,14 @@ minetest.register_craftitem("experimental:tester_tool_1", {
 	end,
 })
 
+minetest.register_craft({
+	output = 'experimental:tester_tool_1',
+	recipe = {
+		{'group:crumbly'},
+		{'group:crumbly'},
+	}
+})
+
 minetest.log("experimental modname="..dump(minetest.get_current_modname()))
 minetest.log("experimental modpath="..dump(minetest.get_modpath("experimental")))
 minetest.log("experimental worldpath="..dump(minetest.get_worldpath()))

src/craftdef.cpp

@@ -27,6 +27,26 @@ with this program; if not, write to the Free Software Foundation, Inc.,
 #include "gamedef.h"
 #include "inventory.h"
 
+// Check if input matches recipe
+// Takes recipe groups into account
+static bool inputItemMatchesRecipe(const std::string &inp_name,
+		const std::string &rec_name, IItemDefManager *idef)
+{
+	// Exact name
+	if(inp_name == rec_name)
+		return true;
+	
+	// Group
+	if(rec_name.substr(0,6) == "group:" && idef->isKnown(inp_name)){
+		std::string rec_group = rec_name.substr(6);
+		const struct ItemDefinition &def = idef->get(inp_name);
+		if(itemgroup_get(def.groups, rec_group) != 0)
+			return true;
+	}
+	
+	// Didn't match
+	return false;
+}
 
 // Deserialize an itemstring then return the name of the item
 static std::string craftGetItemName(const std::string &itemstring, IGameDef *gamedef)
@@ -403,9 +423,9 @@ bool CraftDefinitionShaped::check(const CraftInput &input, IGameDef *gamedef) co
 		unsigned int rec_x = rec_min_x + x;
 		unsigned int rec_y = rec_min_y + y;
 
-		if(
+		if(!inputItemMatchesRecipe(
-			inp_names[inp_y * inp_width + inp_x] !=
+				inp_names[inp_y * inp_width + inp_x],
-			rec_names[rec_y * rec_width + rec_x]
+				rec_names[rec_y * rec_width + rec_x], gamedef->idef())
 		){
 			return false;
 		}