airboat/init.lua

local function is_water(pos)
	local nn = minetest.get_node(pos).name
	return minetest.get_item_group(nn, "water") ~= 0
end


local function get_sign(i)
	if i == 0 then
		return 0
	else
		return i / math.abs(i)
	end
end


local function get_velocity(v, yaw, y)
	local x = -math.sin(yaw) * v
	local z =  math.cos(yaw) * v
	return {x = x, y = y, z = z}
end


local function get_v(v)
	return math.sqrt(v.x ^ 2 + v.z ^ 2)
end


local airboat = {
	physical = true,
	collisionbox = {-0.85, -1.5, -0.85, 0.85, 1.5, 0.85},
	visual = "wielditem",
	visual_size = {x = 2.0, y = 2.0}, -- Scale up of nodebox is these * 1.5
	textures = {"airboat:airboat_nodebox"},

	driver = nil,
	v = 0,
	vy = 0,
	removed = false
}


function airboat.on_rightclick(self, clicker)
	if not clicker or not clicker:is_player() then
		return
	end
	local name = clicker:get_player_name()
	if self.driver and clicker == self.driver then
		self.driver = nil
		clicker:set_detach()
		player_api.player_attached[name] = false
		player_api.set_animation(clicker, "stand" , 30)
		local pos = clicker:getpos()
		minetest.after(0.1, function()
			clicker:setpos(pos)
		end)
	elseif not self.driver then
		local attach = clicker:get_attach()
		if attach and attach:get_luaentity() then
			local luaentity = attach:get_luaentity()
			if luaentity.driver then
				luaentity.driver = nil
			end
			clicker:set_detach()
		end
		self.driver = clicker
		clicker:set_attach(self.object, "",
			{x = 0, y = -1, z = 0}, {x = 0, y = 0, z = 0})
		player_api.player_attached[name] = true
		minetest.after(0.2, function()
			player_api.set_animation(clicker, "sit" , 30)
		end)
		clicker:set_look_horizontal(self.object:getyaw())
	end
end


function airboat.on_activate(self, staticdata, dtime_s)
	self.object:set_armor_groups({immortal = 1})
end


function airboat.on_punch(self, puncher)
	if not puncher or not puncher:is_player() or self.removed then
		return
	end
	if self.driver and puncher == self.driver then
		self.driver = nil
		puncher:set_detach()
		player_api.player_attached[puncher:get_player_name()] = false
	end
	if not self.driver then
		self.removed = true
		local inv = puncher:get_inventory()
		if not (creative and creative.is_enabled_for
				and creative.is_enabled_for(puncher:get_player_name()))
				or not inv:contains_item("main", "airboat:airboat") then
			local leftover = inv:add_item("main", "airboat:airboat")
			if not leftover:is_empty() then
				minetest.add_item(self.object:getpos(), leftover)
			end
		end
		-- Delay remove to ensure player is detached
		minetest.after(0.1, function()
			self.object:remove()
		end)
	end
end


function airboat.on_step(self, dtime)
	self.v = get_v(self.object:getvelocity()) * get_sign(self.v)
	self.vy = self.object:getvelocity().y
	if self.driver then
		local ctrl = self.driver:get_player_control()
		local yaw = self.object:getyaw()
		if ctrl.up then
			self.v = self.v + 0.1
		elseif ctrl.down then
			self.v = self.v - 0.1
		end
		if ctrl.left then
			self.object:setyaw(yaw + (1 + dtime) * 0.02)
		elseif ctrl.right then
			self.object:setyaw(yaw - (1 + dtime) * 0.02)
		end
		if ctrl.jump then
			self.vy = self.vy + 0.075
		elseif ctrl.sneak then
			self.vy = self.vy - 0.075
		end
	end
	local velo = self.object:getvelocity()
	if self.v == 0 and self.vy == 0 and
			velo.x == 0 and velo.y == 0 and velo.z == 0 then
		self.object:setpos(self.object:getpos())
		return
	end

	local s = get_sign(self.v)
	self.v = self.v - 0.02 * s
	if s ~= get_sign(self.v) then
		self.v = 0
	end
	if math.abs(self.v) > 6 then
		self.v = 6 * get_sign(self.v)
	end

	local sy = get_sign(self.vy)
	self.vy = self.vy - 0.04 * sy
	if sy ~= get_sign(self.vy) then
		self.vy = 0
	end
	if math.abs(self.vy) > 4 then
		self.vy = 4 * get_sign(self.vy)
	end

	local new_acce = {x = 0, y = 0, z = 0}
	local p = self.object:getpos()
	p.y = p.y - 1.5
	if is_water(p) then
		new_acce = {x = 0, y = 20, z = 0}
	end

	self.object:setpos(self.object:getpos())
	local new_velo = get_velocity(self.v, self.object:getyaw(), self.vy)
	self.object:setvelocity(new_velo)
	self.object:setacceleration(new_acce)
end


minetest.register_entity("airboat:airboat", airboat)


minetest.register_craftitem("airboat:airboat", {
	description = "Airboat",
	inventory_image = "airboat_airboat_inv.png",
	wield_scale = {x = 4, y = 4, z = 4},
	liquids_pointable = true,
	groups = {flammable = 2},

	on_place = function(itemstack, placer, pointed_thing)
		local under = pointed_thing.under
		local node = minetest.get_node(under)
		local udef = minetest.registered_nodes[node.name]
		if udef and udef.on_rightclick and
				not (placer and placer:is_player() and
				placer:get_player_control().sneak) then
			return udef.on_rightclick(under, node, placer, itemstack,
				pointed_thing) or itemstack
		end

		if pointed_thing.type ~= "node" then
			return itemstack
		end
		pointed_thing.under.y = pointed_thing.under.y + 2
		boat = minetest.add_entity(pointed_thing.under, "airboat:airboat")
		if boat then
			if placer then
				boat:setyaw(placer:get_look_horizontal())
			end
			local player_name = placer and placer:get_player_name() or ""
			if not (creative and creative.is_enabled_for and
					creative.is_enabled_for(player_name)) then
				itemstack:take_item()
			end
		end
		return itemstack
	end,
})


minetest.register_node("airboat:airboat_nodebox", {
	description = "Airboat Nodebox",
	tiles = { -- top base right left front back
		"airboat_airboat_top.png",
		"airboat_airboat_base.png",
		"airboat_airboat_right.png",
		"airboat_airboat_left.png",
		"airboat_airboat_front.png",
		"airboat_airboat_back.png",
	},
	paramtype = "light",
	drawtype = "nodebox",
	node_box = {
		type = "fixed",
		fixed = { -- widmin heimin lenmin widmax heimax lenmax
			{-0.271, -0.167, -0.5,  0.271, 0.375, 0.5}, -- Envelope
			{-0.167, -0.5, -0.25,   0.167, -0.167, 0.25}, -- Gondola
			{-0.021, 0.375, -0.5,   0.021, 0.5, -0.25}, -- Top fin
			{-0.021, -0.292, -0.5,  0.021, -0.167, -0.25}, -- Base fin
			{-0.396, 0.083, -0.5,   -0.271, 0.125, -0.25}, -- Left fin
			{0.271, 0.083, -0.5,    0.396, 0.125, -0.25}, -- Right fin
		},
	},
	groups = {not_in_creative_inventory = 1},
})