nssm/nssm_spears.lua

local creative_mode = minetest.settings:get_bool("creative_mode")

local function is_walkable(node_name)

	if not minetest.registered_nodes[node_name] then
		return true -- non-existent, we should stop the spear !
	end

	if minetest.registered_nodes[node_name].walkable == true
	or minetest.registered_nodes[node_name].walkable == nil then
		return true
	end

	return false
end


local function spears_shot(itemstack, player)

	local spear = itemstack:get_name() .. "_entity"
	local speed = 16
	local gravity = 9.8

	if spear == "nssm:spear_of_peace_entity" then
		speed = 32
		gravity = 9.8
	end

	local drag = .3
	local playerpos = player:get_pos()
	local dir = player:get_look_dir()
	local obj = minetest.add_entity({
		x = playerpos.x,
		y = playerpos.y + 1.5,
		z = playerpos.z}, spear)

	obj:set_velocity({x = dir.x * speed, y = dir.y * speed, z = dir.z * speed})
	obj:set_acceleration({x = -dir.x * drag, y = -gravity, z = -dir.z * drag})
	obj:set_yaw(player:get_look_horizontal() + math.pi / 2)
	minetest.sound_play("spears_sound", {pos = playerpos}, true)
	obj:get_luaentity().wear = itemstack:get_wear()
	obj:get_luaentity().shooter = player

	return true
end


local function spears_set_entity(kind, eq, toughness, breadth)

	local spearname = "nssm:spear_" .. kind
	local spearentityname = spearname .. "_entity"
	local maxwear = 65535
	local weardown = maxwear / toughness

	breadth = breadth or 1

	local SPEAR_ENTITY = {

		initial_properties = {

			physical = false,
			visual = "wielditem",
			visual_size = {x = 0.15, y = 0.1},
			textures = {spearname},
			collisionbox = {0,0,0,0,0,0},
		},

		timer = 0,
		lastpos = {},

		on_punch = function(self, puncher)

			-- pick up item
			if puncher then

				if puncher:is_player() then

					local stack = {name=spearname, wear=self.wear}
					local inv = puncher:get_inventory()

					if inv:room_for_item("main", stack) then

						inv:add_item("main", stack)

						self.object:remove()
					end
				end
			end
		end
	}

	SPEAR_ENTITY.on_step = function(self, dtime)

		self.timer = self.timer + dtime

		local pos = self.object:get_pos()
		local node = minetest.get_node(pos)

		if not self.wear then

			self.object:remove()

			return
		end

		-- pos exists --> entity has moved at least once
		if self.lastpos.x then

			if node.name ~= "air" and is_walkable(node.name) then

				self.object:remove()

				local halfweardown = weardown / 2

				if self.wear + halfweardown < maxwear then

					minetest.add_item(self.lastpos, {
						name = spearname,
						wear = self.wear + halfweardown
					})
				end

			else
				local objs = minetest.get_objects_inside_radius({
					x = pos.x,
					y = pos.y,
					z = pos.z}, 1.5 * breadth)

				local add_at

				for k, obj in pairs(objs) do

					if obj:get_luaentity() ~= nil then

						if obj:get_luaentity().name ~= spearentityname
						and obj:get_luaentity().name ~= "__builtin:item" then

							if not (obj:is_player()
							and obj:get_luaentity().shooter:get_player_name()
									== obj:get_player_name() ) then

								local speed = vector.length(self.object:get_velocity())
								local damage = (speed + eq) ^ 1.12 - 20

								obj:punch(self.object, 1.0, {
									full_punch_interval = 1.0,
									damage_groups = {fleshy = damage},
								}, nil)

								self.object:remove()

								-- Wear down for each mob hit
								if self.wear + weardown < maxwear then
									self.wear = self.wear + weardown
									add_at = {
										pos = self.lastpos,
										def = {name = spearname, wear  =self.wear}
									}
								end
							end
						end

						break
					end
				end

				if add_at then
					minetest.add_item(add_at.pos, add_at.def)
				end
			end
		end

		self.lastpos = {x = pos.x, y = pos.y, z = pos.z}
	end

	return SPEAR_ENTITY
end

--Tools

function spears_register_spear(kind, desc, eq, toughness, material, scale)

	scale = scale or 1

	minetest.register_tool("nssm:spear_" .. kind, {
		description = desc .. " Spear",
		wield_image = "spear_" .. kind .. ".png",
		inventory_image = "spear_" .. kind .. ".png^[transform4",
		wield_scale= {x = 2 * scale, y = 1 * scale, z = 1 * scale},

		on_drop = function(itemstack, user, pointed_thing)

			spears_shot(itemstack, user)

			if not creative_mode then
				itemstack:take_item()
			end

			return itemstack
		end,

		on_place = function(itemstack, user, pointed_thing)

			minetest.add_item(pointed_thing.above, itemstack)

			if not creative_mode then
				itemstack:take_item()
			end

			return itemstack
		end,

		tool_capabilities = {
			full_punch_interval = 1.3,
			max_drop_level = 1,
			groupcaps = {
				snappy = {
					times = {[3] = 0.2, [2] = 0.2, [1] = 0.2},
					uses = toughness,
					maxlevel = 1
				}
			},
			damage_groups = {fleshy = eq},
		}
	})

	local SPEAR_ENTITY = spears_set_entity(kind, eq, toughness, scale)

	minetest.register_entity("nssm:spear_" .. kind .. "_entity", SPEAR_ENTITY)

	minetest.register_craft({
		output = "nssm:spear_" .. kind,
		recipe = {
			{"group:wood", "group:wood", material}
		}
	})

	minetest.register_craft({
		output = "nssm:spear_" .. kind,
		recipe = {
			{material, "group:wood", "group:wood"}
		}
	})
end


spears_register_spear("ant", "Ant", 6, 50, "nssm:ant_mandible")

spears_register_spear("mantis", "Mantis", 6, 20, "nssm:mantis_claw")

spears_register_spear("manticore", "Manticore", 8, 16, "nssm:manticore_spine")

spears_register_spear("ice_tooth", "Ice Tooth", 16, 200, "nssm:ice_tooth")

spears_register_spear("little_ice_tooth", "Little Ice Tooth", 7, 20, "nssm:little_ice_tooth")

spears_register_spear("duck_beak", "Duck Beak", 5, 12, "nssm:duck_beak")

spears_register_spear("felucco_horn", "Felucco Horn", 7, 18, "nssm:felucco_horn")

spears_register_spear("of_peace", "Grand Peace", 30, 300, "nssm:wrathful_moranga", 2)