VoxeLibre/mods/ITEMS/mcl_throwing/throwable.lua

-- 
-- Snowballs and other throwable items
--

local GRAVITY = tonumber(minetest.setting_get("movement_gravity"))

local entity_mapping = {
	["mcl_throwing:snowball"] = "mcl_throwing:snowball_entity",
	["mcl_throwing:egg"] = "mcl_throwing:egg_entity",
	["mcl_throwing:ender_pearl"] = "mcl_throwing:ender_pearl_entity",
}

local velocities = {
	["mcl_throwing:snowball_entity"] = 22,
	["mcl_throwing:egg_entity"] = 22,
	["mcl_throwing:ender_pearl_entity"] = 22,
}

mcl_throwing.throw = function(throw_item, pos, dir, velocity)
	if velocity == nil then
		velocity = velocities[entity_name]
	end
	if velocity == nil then
		velocity = 22
	end

	local itemstring = ItemStack(throw_item):get_name()
	local obj = minetest.add_entity(pos, entity_mapping[itemstring])
	obj:setvelocity({x=dir.x*velocity, y=dir.y*velocity, z=dir.z*velocity})
	obj:setacceleration({x=dir.x*-3, y=-GRAVITY, z=dir.z*-3})
	return obj
end

-- Throw item
local throw_function = function(entity_name, velocity)
	local func = function(item, player, pointed_thing)
		local playerpos = player:getpos()
		local dir = player:get_look_dir()
		local obj = mcl_throwing.throw(item, {x=playerpos.x, y=playerpos.y+1.5, z=playerpos.z}, dir, velocity)
		obj:get_luaentity()._thrower = player:get_player_name()
		if not minetest.setting_getbool("creative_mode") then
			item:take_item()
		end
		return item
	end
	return func
end

-- Staticdata handling because objects may want to be reloaded
local get_staticdata = function(self)
	local data = {
		_lastpos = self._lastpos,
		_thrower = self._thrower,
	}
	return minetest.serialize(data)
end

local on_activate = function(self, staticdata, dtime_s)
	local data = minetest.deserialize(staticdata)
	if data then
		self._lastpos = data._lastpos
		self._thrower = data._thrower
	end
end

-- The snowball entity
local snowball_ENTITY={
	physical = false,
	timer=0,
	textures = {"mcl_throwing_snowball.png"},
	visual_size = {x=0.5, y=0.5},
	collisionbox = {0,0,0,0,0,0},

	get_staticdata = get_staticdata,
	on_activate = on_activate,

	_lastpos={},
}
local egg_ENTITY={
	physical = false,
	timer=0,
	textures = {"mcl_throwing_egg.png"},
	visual_size = {x=0.45, y=0.45},
	collisionbox = {0,0,0,0,0,0},

	get_staticdata = get_staticdata,
	on_activate = on_activate,

	_lastpos={},
}
-- Ender pearl entity
local pearl_ENTITY={
	physical = false,
	timer=0,
	textures = {"mcl_throwing_ender_pearl.png"},
	visual_size = {x=0.9, y=0.9},
	collisionbox = {0,0,0,0,0,0},

	get_staticdata = get_staticdata,
	on_activate = on_activate,

	_lastpos={},
	_thrower = nil,		-- Player ObjectRef of the player who threw the ender pearl
}

-- Snowball on_step()--> called when snowball is moving.
local snowball_on_step = function(self, dtime)
	self.timer=self.timer+dtime
	local pos = self.object:getpos()
	local node = minetest.get_node(pos)
	local def = minetest.registered_nodes[node.name]

	-- Destroy when hitting a solid node
	if self._lastpos.x~=nil then
		if (def and def.walkable) or not def then
			self.object:remove()
			return
		end
	end
	self._lastpos={x=pos.x, y=pos.y, z=pos.z} -- Set _lastpos-->Node will be added at last pos outside the node
end

-- Movement function of egg
local egg_on_step = function(self, dtime)
	self.timer=self.timer+dtime
	local pos = self.object:getpos()
	local node = minetest.get_node(pos)
	local def = minetest.registered_nodes[node.name]

	-- Destroy when hitting a solid node
	if self._lastpos.x~=nil then
		if (def and def.walkable) or not def then
			-- 1/8 chance to spawn a chick
			-- FIXME: Spawn chicks instead of chickens
			-- FIXME: Chicks have a quite good chance to spawn in walls
			local r = math.random(1,8)
			if r == 1 then
				minetest.add_entity(self._lastpos, "mobs_mc:chicken")

				-- BONUS ROUND: 1/32 chance to spawn 3 additional chicks
				local r = math.random(1,32)
				if r == 1 then
					local offsets = {
						{ x=0.7, y=0, z=0 },
						{ x=-0.7, y=0, z=-0.7 },
						{ x=-0.7, y=0, z=0.7 },
					}
					for o=1, 3 do
						local pos = vector.add(self._lastpos, offsets[o])
						minetest.add_entity(pos, "mobs_mc:chicken")
					end
				end
			end
			self.object:remove()
			return
		end
	end
	self._lastpos={x=pos.x, y=pos.y, z=pos.z} -- Set lastpos-->Node will be added at last pos outside the node
end

-- Movement function of ender pearl
local pearl_on_step = function(self, dtime)
	self.timer=self.timer+dtime
	local pos = self.object:getpos()
	pos.y = math.floor(pos.y)
	local node = minetest.get_node(pos)
	local def = minetest.registered_nodes[node.name]

	-- Destroy when hitting a solid node
	if self._lastpos.x~=nil then
		-- No teleport for hitting ignore for now. Otherwise the player could get stuck.
		-- FIXME: This also means the player loses an ender pearl for throwing into unloaded areas
		if node.name == "ignore" then
			self.object:remove()
		elseif (def and def.walkable) or not def then
			local player = minetest.get_player_by_name(self._thrower)
			if player then
				-- Teleport and hurt player

				-- But first determine good teleport position
				local v = self.object:getvelocity()
				v = vector.normalize(v)

				-- Zero-out the two axes with a lower absolute value than
				-- the axis with the strongest force
				local lv, ld
				lv, ld = math.abs(v.y), "y"
				if math.abs(v.x) > lv then
					lv, ld = math.abs(v.x), "x"
				end
				if math.abs(v.z) > lv then
					lv, ld = math.abs(v.z), "z"
				end
				if ld ~= "x" then v.x = 0 end
				if ld ~= "y" then v.y = 0 end
				if ld ~= "z" then v.z = 0 end

				-- Final tweaks to the teleporting pos, based on direction
				local dir = {x=0, y=0, z=0}

				-- Impact from the side
				dir.x = v.x * -1
				dir.z = v.z * -1

				-- Special case: top or bottom of node
				if v.y > 0 then
					-- We need more space when impact is from below
					dir.y = -2.3
				elseif v.y < 0 then
					-- Standing on top
					dir.y = 0.5
				end

				-- Final teleportation position
				local telepos = vector.add(pos, dir)

				player:setpos(telepos)
				player:set_hp(player:get_hp() - 5)

			end
			self.object:remove()
			return
		end
	end
	self._lastpos={x=pos.x, y=pos.y, z=pos.z} -- Set lastpos-->Node will be added at last pos outside the node
end

snowball_ENTITY.on_step = snowball_on_step
egg_ENTITY.on_step = egg_on_step
pearl_ENTITY.on_step = pearl_on_step

minetest.register_entity("mcl_throwing:snowball_entity", snowball_ENTITY)
minetest.register_entity("mcl_throwing:egg_entity", egg_ENTITY)
minetest.register_entity("mcl_throwing:ender_pearl_entity", pearl_ENTITY)

local how_to_throw = "Hold it in your and and leftclick to throw."

-- Snowball
minetest.register_craftitem("mcl_throwing:snowball", {
	description = "Snowball",
	_doc_items_longdesc = "Snowballs can be thrown or launched from a dispenser for fun. Hitting something with a snowball does nothing.",
	_doc_items_usagehelp = how_to_throw,
	inventory_image = "mcl_throwing_snowball.png",
	stack_max = 16,
	on_use = throw_function("mcl_throwing:snowball_entity"),
	on_construct = function(pos)
	pos.y = pos.y - 1
		if minetest.get_node(pos).name == "default:dirt_with_grass" then
			minetest.set_node(pos, {name="default:dirt_with_snow"})
		end
	end,
})

-- Egg
minetest.register_craftitem("mcl_throwing:egg", {
	description = "Egg",
	_doc_items_longdesc = "Eggs can be thrown or launched from a dispenser and breaks on impact. There is a small chance that 1 or even 4 chickens will pop out of the egg when it hits the ground.",
	_doc_items_usagehelp = how_to_throw,
	inventory_image = "mcl_throwing_egg.png",
	stack_max = 16,
	on_use = throw_function("mcl_throwing:egg_entity"),
	groups = { craftitem = 1 },
})

-- Ender Pearl
minetest.register_craftitem("mcl_throwing:ender_pearl", {
	description = "Ender Pearl",
	_doc_items_longdesc = "An ender pearl is an item which can be used for teleportation at the cost of health. It can be thrown and teleport the thrower to its impact location when it hits a block. Each teleportation hurts the user by 5 hit points.",
	_doc_items_usagehelp = how_to_throw,
	wield_image = "mcl_throwing_ender_pearl.png",
	inventory_image = "mcl_throwing_ender_pearl.png",
	stack_max = 16,
	on_use = throw_function("mcl_throwing:ender_pearl_entity"),
})