Implement dropped items as LuaEntities; leave the old ones as is for compatibility

builtin/item_entity.lua

@@ -0,0 +1,90 @@
+-- Minetest: builtin/item_entity.lua
+
+function minetest.spawn_item(pos, item)
+	-- Take item in any format
+	local stack = ItemStack(item)
+	local obj = minetest.env:add_entity(pos, "__builtin:item")
+	obj:get_luaentity():set_item(stack:to_string())
+	return obj
+end
+
+minetest.register_entity("__builtin:item", {
+	initial_properties = {
+		hp_max = 1,
+		physical = true,
+		collisionbox = {-0.25,-0.25,-0.25, 0.25,0.25,0.25},
+		visual = "sprite",
+		visual_size = {x=0.5, y=0.5},
+		textures = {""},
+		spritediv = {x=1, y=1},
+		initial_sprite_basepos = {x=0, y=0},
+		is_visible = false,
+	},
+	
+	itemstring = '',
+	physical_state = true,
+
+	set_item = function(self, itemstring)
+		self.itemstring = itemstring
+		local stack = ItemStack(itemstring)
+		local itemtable = stack:to_table()
+		local itemname = nil
+		if itemtable then
+			itemname = stack:to_table().name
+		end
+		local item_texture = nil
+		if minetest.registered_items[itemname] then
+			item_texture = minetest.registered_items[itemname].inventory_image
+		end
+		item_texture = item_texture or "unknown_item.png"
+		self.object:set_properties({
+			textures = {item_texture},
+			is_visible = true,
+		})
+	end,
+
+	get_staticdata = function(self)
+		return self.itemstring
+	end,
+
+	on_activate = function(self, staticdata)
+		self.itemstring = staticdata
+		self.object:set_armor_groups({immortal=1})
+		self.object:setvelocity({x=0, y=2, z=0})
+		self.object:setacceleration({x=0, y=-10, z=0})
+		self:set_item(self.itemstring)
+	end,
+
+	on_step = function(self, dtime)
+		local p = self.object:getpos()
+		p.y = p.y - 0.3
+		local nn = minetest.env:get_node(p).name
+		if minetest.registered_nodes[nn].walkable then
+			if self.physical_state then
+				self.object:setvelocity({x=0,y=0,z=0})
+				self.object:setacceleration({x=0, y=0, z=0})
+				self.physical_state = false
+				self.object:set_properties({
+					physical = false
+				})
+			end
+		else
+			if not self.physical_state then
+				self.object:setvelocity({x=0,y=0,z=0})
+				self.object:setacceleration({x=0, y=-10, z=0})
+				self.physical_state = true
+				self.object:set_properties({
+					physical = true
+				})
+			end
+		end
+	end,
+
+	on_punch = function(self, hitter)
+		if self.itemstring ~= '' then
+			hitter:get_inventory():add_item("main", self.itemstring)
+		end
+		self.object:remove()
+	end,
+})
+