frist commit

LICENSE

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+                   GNU LESSER GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
+
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+

README.md

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+Minetest 5.4 mod: Ultralight Trike
+========================================
+
+As the title say, it's a flying machine
+
+This one tries to implement some flight physics, using the mobkit mod.
+In order to fly, it is necessary to first supply the aircraft with biofuel.
+Then with a gallon selected, punch it against the trike.
+You can use 10 of them to fill the tank. See the fuel gauge on the aircraft
+panel (right below, with a green F). To embark, click with the right button.
+While the machine is off, it is possible to move it using the sneak and jump keys (shift an space).
+W ans S move the wing, to increase and decrease the attack angle (it's important).
+Right and Left (A and D) controls the yaw.
+
+Then to fly, start the engine with the special key E. Press jump (space)
+to increase the engine power (check the panel for the indicator marked with a yellow P).
+Adjust to the maximum. Push the wing (W) and wait for speed to lift.
+
+During the cruise flight, it is ideal to keep the power setting below the red range,
+to control fuel consumption. Use the climb indicator to stabilize altitude,
+as at high altitudes you lose support and you spend more fuel. 
+
+For landing, a traffic circuit can be made, lowering the power and increasing 
+the angle of attack of the wing to reduce speed and altitude (acting as a flap). 
+Or to force the descent by pulling the wing and pushing it forward when 
+approaching, regulating the speed. 
+
+Care must be taken with impacts, as it causes damage to the aircraft and the pilot, 
+so training landings is essential. 
+
+To brake the aircraft, use the sneak (shift) key until it comes to a complete stop.
+Do not stop the engine before this, or it will reverse when it stops 
+
+To repair damages, you can use the repair tool. It subtracts steel ingots to increase
+airplane hp.
+
+It can be painted using dye of any color you want, you must punch the airplane with the dye.
+
+Biofuel mod can be found here: https://github.com/APercy/minetest_biofuel
+
+-----------------------
+License of source code:
+LGPL v3 (see file LICENSE) 
+
+License of media (textures and sounds):
+---------------------------------------
+engine.ogg and collision.ogg by APercy.
+trike model and tectures by APercy.
+

depends.txt

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+mobkit
+default
+biofuel

init.lua

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+trike={}
+trike.gravity = tonumber(minetest.settings:get("movement_gravity")) or 9.8
+
+trike.colors ={
+    black='#2b2b2b',
+    blue='#0063b0',
+    brown='#8c5922',
+    cyan='#07B6BC',
+    dark_green='#567a42',
+    dark_grey='#6d6d6d',
+    green='#4ee34c',
+    grey='#9f9f9f',
+    magenta='#ff0098',
+    orange='#ff8b0e',
+    pink='#ff62c6',
+    red='#dc1818',
+    violet='#a437ff',
+    white='#FFFFFF',
+    yellow='#ffe400',
+}
+
+dofile(minetest.get_modpath("trike") .. DIR_DELIM .. "trike_crafts.lua")
+dofile(minetest.get_modpath("trike") .. DIR_DELIM .. "trike_control.lua")
+dofile(minetest.get_modpath("trike") .. DIR_DELIM .. "trike_fuel_management.lua")
+dofile(minetest.get_modpath("trike") .. DIR_DELIM .. "trike_custom_physics.lua")
+dofile(minetest.get_modpath("trike") .. DIR_DELIM .. "trike_utilities.lua")
+dofile(minetest.get_modpath("trike") .. DIR_DELIM .. "trike_entities.lua")
+
+--
+-- helpers and co.
+--
+
+local creative_exists = minetest.global_exists("creative")
+
+--
+-- items
+--
+
+settings = Settings(minetest.get_worldpath() .. "/trike_settings.conf")
+local function fetch_setting(name)
+    local sname = name
+    return settings and settings:get(sname) or minetest.settings:get(sname)
+end
+
+trike.restricted = fetch_setting("restricted")
+
+minetest.register_privilege("flight_licence", {
+    description = "Gives a flight licence to the player",
+    give_to_singleplayer = true
+})
+
+

mod.conf

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+name = trike
+depends = mobkit,default,biofuel
+author = APercy
+description = Adds a craftable trike
+title = Trike

trike_control.lua

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+--global constants
+trike.trike_last_time_command = 0
+trike.vector_up = vector.new(0, 1, 0)
+
+dofile(minetest.get_modpath("trike") .. DIR_DELIM .. "trike_utilities.lua")
+
+function trike.check_node_below(obj)
+	local pos_below = obj:get_pos()
+	pos_below.y = pos_below.y - 0.1
+	local node_below = minetest.get_node(pos_below).name
+	local nodedef = minetest.registered_nodes[node_below]
+	local touching_ground = not nodedef or -- unknown nodes are solid
+			nodedef.walkable or false
+	local liquid_below = not touching_ground and nodedef.liquidtype ~= "none"
+	return touching_ground, liquid_below
+end
+
+function trike.control(self, dtime, hull_direction, longit_speed, longit_drag, later_speed, later_drag, accel)
+    trike.trike_last_time_command = trike.trike_last_time_command + dtime
+    if trike.trike_last_time_command > 1 then trike.trike_last_time_command = 1 end
+    if self.driver_name == nil then return end
+	local player = minetest.get_player_by_name(self.driver_name)
+    local retval_accel = accel
+
+    local rudder_limit = 30    
+
+	-- player control
+	if player then
+		local ctrl = player:get_player_control()
+
+        if ctrl.aux1 and trike.trike_last_time_command > 0.3 then
+            trike.trike_last_time_command = 0
+		    if self._engine_running then
+			    self._engine_running = false
+		        -- sound and animation
+                if self.sound_handle then
+                    minetest.sound_stop(self.sound_handle)
+                    self.sound_handle = nil
+                end
+		        self.engine:set_animation_frame_speed(0)
+
+		    elseif self._engine_running == false and self._energy > 0 then
+			    self._engine_running = true
+	            -- sound and animation
+                self.sound_handle = minetest.sound_play({name = "engine"},
+	                {object = self.object, gain = 2.0, pitch = 0.5 + ((self._power_lever/100)/2),max_hear_distance = 32, loop = true,})
+                self.engine:set_animation_frame_speed(60)
+		    end
+        end		
+
+        self._acceleration = 0
+        if self._engine_running then
+            local engineacc = 0
+
+            --compute the acceleration
+            local max_engine_acc = 3.5
+            --engine acceleration calc
+            engineacc = (self._power_lever * max_engine_acc) / 100;
+            self.engine:set_animation_frame_speed(60 + self._power_lever)
+
+            --increase power lever
+            if self._power_lever < 100 and ctrl.jump then
+                self._power_lever = self._power_lever + 1
+                if self._power_lever > 100 then
+                    self._power_lever = 100
+                    engineacc = max_engine_acc
+                else
+                    --sound
+                    minetest.sound_stop(self.sound_handle)
+                    self.sound_handle = minetest.sound_play({name = "engine"},
+		                {object = self.object, gain = 2.0, pitch = 0.5 + ((self._power_lever/100)/2),max_hear_distance = 32, loop = true,})
+                end
+            end
+            --decrease power lever
+            if ctrl.sneak then
+                if self._power_lever > 0 then
+                    self._power_lever = self._power_lever - 1
+                    if self._power_lever < 0 then self._power_lever = 0 end
+                end
+                if self._power_lever <= 0 then
+                    --wheel break
+                    if longit_speed >= 0.1 then
+	                    engineacc = -1
+                    end
+                    if longit_speed <= -0.1 then
+	                    engineacc = 1
+                    end
+                    if abs(longit_speed) < 0.1 then
+	                    self.object:set_velocity(vector.new())
+                    end
+                else
+                    --sound
+                    minetest.sound_stop(self.sound_handle)
+                    self.sound_handle = minetest.sound_play({name = "engine"},
+		                {object = self.object, gain = 2.0, pitch = 0.5 + ((self._power_lever/100)/2),max_hear_distance = 32, loop = true,})
+                end
+            end
+            --do not exceed
+            local max_speed = 6
+            if longit_speed > max_speed then
+                engineacc = engineacc - (longit_speed-max_speed)
+                if engineacc < 0 then engineacc = 0 end
+            end
+            self._acceleration = engineacc
+        else
+	        local paddleacc
+	        if longit_speed < 1.0 and ctrl.jump then
+		        paddleacc = 0.5
+	        elseif longit_speed > -1.0 and ctrl.sneak then
+		        paddleacc = -0.5
+	        end
+	        self._acceleration = paddleacc
+        end
+
+        local hull_acc = vector.multiply(hull_direction,self._acceleration)
+        retval_accel=vector.add(accel,hull_acc)
+
+        --wing
+        local wing_limit = 10
+		if ctrl.down then
+			self._angle_of_attack = math.max(self._angle_of_attack-10*dtime,1)
+		elseif ctrl.up then
+			self._angle_of_attack = math.min(self._angle_of_attack+10*dtime,wing_limit)
+		end
+
+		-- yaw
+		if ctrl.right then
+			self._rudder_angle = math.max(self._rudder_angle-30*dtime,-rudder_limit)
+		elseif ctrl.left then
+			self._rudder_angle = math.min(self._rudder_angle+30*dtime,rudder_limit)
+		end
+	end
+
+    if longit_speed > 0 then
+        local factor = 1
+        if self._rudder_angle > 0 then factor = -1 end
+        local correction = (rudder_limit*(longit_speed/1000)) * factor
+        self._rudder_angle = self._rudder_angle + correction
+    end
+
+    return retval_accel
+end
+
+

trike_crafts.lua

@@ -0,0 +1,85 @@
+-- engine
+minetest.register_craftitem("trike:wing",{
+	description = "Trike wing",
+	inventory_image = "icon3.png",
+})
+-- hull
+minetest.register_craftitem("trike:fuselage",{
+	description = "Trike body",
+	inventory_image = "icon2.png",
+})
+
+
+-- trike
+minetest.register_craftitem("trike:trike", {
+	description = "Ultralight Trike",
+	inventory_image = "icon1.png",
+    liquids_pointable = false,
+
+	on_place = function(itemstack, placer, pointed_thing)
+		if pointed_thing.type ~= "node" then
+			return
+		end
+        
+        local pointed_pos = pointed_thing.under
+        local node_below = minetest.get_node(pointed_pos).name
+        local nodedef = minetest.registered_nodes[node_below]
+        if nodedef.liquidtype == "none" then
+			pointed_pos.y=pointed_pos.y+1.5
+			local trike = minetest.add_entity(pointed_pos, "trike:trike")
+			if trike and placer then
+                local ent = trike:get_luaentity()
+                local owner = placer:get_player_name()
+                ent.owner = owner
+				trike:set_yaw(placer:get_look_horizontal())
+				itemstack:take_item()
+			end
+        end
+
+		return itemstack
+	end,
+})
+
+-- trike repair
+minetest.register_craftitem("trike:repair_tool",{
+	description = "Trike repair tool",
+	inventory_image = "repair_tool.png",
+})
+
+--
+-- crafting
+--
+
+if minetest.get_modpath("default") then
+	minetest.register_craft({
+		output = "trike:wing",
+		recipe = {
+			{"",           "wool:white",          ""          },
+			{"wool:white", "default:steel_ingot", "wool:white"},
+			{"farming:string", "wool:white",      "farming:string"},
+		}
+	})
+	minetest.register_craft({
+		output = "trike:fuselage",
+		recipe = {
+			{"",                    "default:diamondblock", ""},
+			{"default:steel_ingot", "default:steel_ingot",  "default:steel_ingot"},
+			{"default:steel_ingot", "default:mese_block",   "default:steel_ingot"},
+		}
+	})
+	minetest.register_craft({
+		output = "trike:trike",
+		recipe = {
+			{"",                  ""},
+			{"trike:fuselage", "trike:wing"},
+		}
+	})
+    minetest.register_craft({
+	    output = "trike:repair_tool",
+	    recipe = {
+		    {"default:steel_ingot", "", "default:steel_ingot"},
+		    {"", "default:steel_ingot", ""},
+		    {"", "default:steel_ingot", ""},
+	    },
+    })
+end

trike_custom_physics.lua

@@ -0,0 +1,66 @@
+local min = math.min
+local abs = math.abs
+local deg = math.deg
+
+function trike.physics(self)
+	local vel=self.object:get_velocity()
+		-- dumb friction
+	--[[if self.isonground and not self.isinliquid then
+		self.object:set_velocity({x= vel.x> 0.2 and vel.x*mobkit.friction or 0,
+								y=vel.y,
+								z=vel.z > 0.2 and vel.z*mobkit.friction or 0})
+	end]]--
+	
+	-- bounciness
+	if self.springiness and self.springiness > 0 then
+		local vnew = vector.new(vel)
+		
+		if not self.collided then						-- ugly workaround for inconsistent collisions
+			for _,k in ipairs({'y','z','x'}) do			
+				if vel[k]==0 and abs(self.lastvelocity[k])> 0.1 then 
+					vnew[k]=-self.lastvelocity[k]*self.springiness 
+				end
+			end
+		end
+		
+		if not vector.equals(vel,vnew) then
+			self.collided = true
+		else
+			if self.collided then
+				vnew = vector.new(self.lastvelocity)
+			end
+			self.collided = false
+		end
+		
+		self.object:set_velocity(vnew)
+	end
+	
+	-- buoyancy
+	local surface = nil
+	local surfnodename = nil
+	local spos = mobkit.get_stand_pos(self)
+	spos.y = spos.y+0.01
+	-- get surface height
+	local snodepos = mobkit.get_node_pos(spos)
+	local surfnode = mobkit.nodeatpos(spos)
+	while surfnode and (surfnode.drawtype == 'liquid' or surfnode.drawtype == 'flowingliquid') do
+		surfnodename = surfnode.name
+		surface = snodepos.y +0.5
+		if surface > spos.y+self.height then break end
+		snodepos.y = snodepos.y+1
+		surfnode = mobkit.nodeatpos(snodepos)
+	end
+	self.isinliquid = surfnodename
+	if surface then				-- standing in liquid
+--		self.isinliquid = true
+		local submergence = min(surface-spos.y,self.height)/self.height
+--		local balance = self.buoyancy*self.height
+		local buoyacc = mobkit.gravity*(self.buoyancy-submergence)
+		mobkit.set_acceleration(self.object,
+			{x=-vel.x*self.water_drag,y=buoyacc-vel.y*abs(vel.y)*0.4,z=-vel.z*self.water_drag})
+	else
+--		self.isinliquid = false
+		self.object:set_acceleration({x=0,y=mobkit.gravity,z=0})
+	end
+
+end

trike_entities.lua

@@ -0,0 +1,459 @@
+dofile(minetest.get_modpath("trike") .. DIR_DELIM .. "trike_global_definitions.lua")
+
+--
+-- entity
+--
+
+trike.vector_up = vector.new(0, 1, 0)
+
+minetest.register_entity('trike:engine',{
+initial_properties = {
+	physical = false,
+	collide_with_objects=false,
+	pointable=false,
+	visual = "mesh",
+	mesh = "trike_propeller.b3d",
+    --visual_size = {x = 3, y = 3, z = 3},
+	textures = {"trike_rotor.png", "trike_black.png",},
+	},
+	
+    on_activate = function(self,std)
+	    self.sdata = minetest.deserialize(std) or {}
+	    if self.sdata.remove then self.object:remove() end
+    end,
+	    
+    get_staticdata=function(self)
+      self.sdata.remove=true
+      return minetest.serialize(self.sdata)
+    end,
+	
+})
+
+minetest.register_entity('trike:front_wheel',{
+initial_properties = {
+	physical = false,
+	collide_with_objects=false,
+	pointable=false,
+	visual = "mesh",
+	mesh = "trike_front_wheel.b3d",
+    --visual_size = {x = 3, y = 3, z = 3},
+	textures = {"trike_metal.png", "trike_black.png", "trike_metal.png",},
+	},
+	
+    on_activate = function(self,std)
+	    self.sdata = minetest.deserialize(std) or {}
+	    if self.sdata.remove then self.object:remove() end
+    end,
+	    
+    get_staticdata=function(self)
+      self.sdata.remove=true
+      return minetest.serialize(self.sdata)
+    end,
+	
+})
+
+minetest.register_entity('trike:wing',{
+    initial_properties = {
+	    physical = false,
+	    collide_with_objects=true,
+	    pointable=false,
+	    visual = "mesh",
+	    mesh = "trike_wing.b3d",
+        backface_culling = false,
+	    textures = {"trike_black.png", "trike_black.png", "trike_metal.png", "trike_wing_color.png", "trike_wing.png"},
+	},
+    _color="",
+	
+    on_activate = function(self, std)
+	    self.sdata = minetest.deserialize(std) or {}
+	    if self.sdata.remove then self.object:remove() end
+    end,
+	    
+    get_staticdata=function(self)
+      self.sdata.remove=true
+      return minetest.serialize(self.sdata)
+    end,
+
+})
+
+--
+-- fuel
+--
+minetest.register_entity('trike:pointer',{
+initial_properties = {
+	physical = false,
+	collide_with_objects=false,
+	pointable=false,
+	visual = "mesh",
+	mesh = "pointer.b3d",
+    visual_size = {x = 0.4, y = 0.4, z = 0.4},
+	textures = {"trike_grey.png"},
+	},
+	
+    on_activate = function(self,std)
+	    self.sdata = minetest.deserialize(std) or {}
+	    if self.sdata.remove then self.object:remove() end
+    end,
+	    
+    get_staticdata=function(self)
+      self.sdata.remove=true
+      return minetest.serialize(self.sdata)
+    end,
+})
+
+minetest.register_entity("trike:trike", {
+	initial_properties = {
+	    physical = true,
+        collide_with_objects = true,
+	    collisionbox = {-1.2, 0.0, -1.2, 1.2, 3, 1.2}, --{-1,0,-1, 1,0.3,1},
+	    selectionbox = {-1, 0, -1, 1, 1, 1},
+	    visual = "mesh",
+	    mesh = "trike_body.b3d",
+        textures = {"trike_black.png", "trike_metal.png", "trike_metal.png", "trike_metal.png",
+                    "trike_metal.png", "trike_metal.png", "trike_painting.png", "trike_black.png",
+                    "trike_white.png", "trike_black.png", "trike_black.png", "trike_black.png", 
+                    "trike_grey.png", "trike_panel.png", "trike_black.png", "trike_metal.png", "trike_black.png"},
+    },
+    textures = {},
+	driver_name = nil,
+	sound_handle = nil,
+    owner = "",
+    static_save = true,
+    infotext = "A nice ultralight",
+    hp_max = 50,
+    buoyancy = 2,
+    physics = trike.physics,
+    _color = "#0063b0",
+    _rudder_angle = 0,
+    _angle_of_attack = 0,
+    _acceleration = 0,
+    _engine_running = false,
+    _angle_of_attack = 2,
+    _power_lever = 0,
+    _energy = 0.001,
+
+    get_staticdata = function(self) -- unloaded/unloads ... is now saved
+        return minetest.serialize({
+            stored_energy = self._energy,
+            stored_owner = self.owner,
+            stored_hp = self.hp_max,
+            stored_color = self._color,
+            stored_power_lever = self._power_lever,
+        })
+    end,
+
+	on_activate = function(self, staticdata, dtime_s)
+        if staticdata ~= "" and staticdata ~= nil then
+            local data = minetest.deserialize(staticdata) or {}
+            self._energy = data.stored_energy
+            self.owner = data.stored_owner
+            self.hp_max = data.stored_hp
+            self._color = data.stored_color
+            self._power_lever = data.stored_power_lever
+            --minetest.debug("loaded: ", self._energy)
+        end
+        trike.setText(self)
+        self.object:set_animation({x = 1, y = 12}, 0, 0, true)
+
+        local pos = self.object:get_pos()
+
+	    local engine=minetest.add_entity(pos,'trike:engine')
+	    engine:set_attach(self.object,'',{x=0,y=0,z=0},{x=0,y=0,z=0})
+		-- set the animation once and later only change the speed
+        engine:set_animation({x = 1, y = 12}, 0, 0, true)
+	    self.engine = engine
+
+	    local wing=minetest.add_entity(pos,'trike:wing')
+	    wing:set_attach(self.object,'',{x=0,y=29,z=0},{x=0,y=0,z=0})
+		-- set the animation once and later only change the speed
+	    self.wing = wing
+
+	    local wheel=minetest.add_entity(pos,'trike:front_wheel')
+	    wheel:set_attach(self.object,'',{x=0,y=0,z=0},{x=0,y=0,z=0})
+		-- set the animation once and later only change the speed
+        wheel:set_animation({x = 1, y = 12}, 0, 0, true)
+	    self.wheel = wheel
+
+	    local fuel_gauge=minetest.add_entity(pos,'trike:pointer')
+        local energy_indicator_angle = trike.get_gauge_angle(self._energy)
+	    fuel_gauge:set_attach(self.object,'',TRIKE_GAUGE_FUEL_POSITION,{x=0,y=0,z=energy_indicator_angle})
+	    self.fuel_gauge = fuel_gauge
+
+	    local power_gauge=minetest.add_entity(pos,'trike:pointer')
+        local power_indicator_angle = trike.get_gauge_angle(self._power_lever)
+	    power_gauge:set_attach(self.object,'',TRIKE_GAUGE_POWER_POSITION,{x=0,y=0,z=power_indicator_angle})
+	    self.power_gauge = power_gauge
+
+	    local climb_gauge=minetest.add_entity(pos,'trike:pointer')
+        local climb_angle = trike.get_gauge_angle(0)
+	    climb_gauge:set_attach(self.object,'',TRIKE_GAUGE_CLIMBER_POSITION,{x=0,y=0,z=climb_angle})
+	    self.climb_gauge = climb_gauge
+
+        trike.paint(self, self.object, self._color, "trike_painting.png")
+        trike.paint(self, self.wing, self._color, "trike_wing_color.png")
+
+		self.object:set_armor_groups({immortal=1})
+
+        mobkit.actfunc(self, staticdata, dtime_s)
+
+	end,
+
+	on_step = function(self, dtime)
+        mobkit.stepfunc(self, dtime)
+
+        local accel_y = self.object:get_acceleration().y
+        local rotation = self.object:get_rotation()
+        local yaw = rotation.y
+		local newyaw=yaw
+        local pitch = rotation.x
+        local newpitch = pitch
+		local roll = rotation.z
+		local newroll=roll
+
+        local velocity = self.object:get_velocity()
+        local hull_direction = mobkit.rot_to_dir(rotation) --minetest.yaw_to_dir(yaw)
+        local nhdir = {x=hull_direction.z,y=0,z=-hull_direction.x}		-- lateral unit vector
+
+        local longit_speed = trike.dot(velocity,hull_direction)
+        local longit_drag = vector.multiply(hull_direction,longit_speed*longit_speed*LONGIT_DRAG_FACTOR*-1*trike.sign(longit_speed))
+		local later_speed = trike.dot(velocity,nhdir)
+        --minetest.chat_send_all('later_speed: '.. later_speed)
+		local later_drag = vector.multiply(nhdir,later_speed*later_speed*LATER_DRAG_FACTOR*-1*trike.sign(later_speed))
+        local accel = vector.add(longit_drag,later_drag)
+
+        local is_attached = trike.checkAttach(self)
+
+		if is_attached then
+            --control
+			accel = trike.control(self, dtime, hull_direction, longit_speed, longit_drag, later_speed, later_drag, accel) or vel
+        else
+            -- for some engine error the player can be detached from the machine, so lets set him attached again
+            trike.checkattachBug(self)
+		end
+        trike.testImpact(self, velocity)
+
+        -- new yaw
+		if math.abs(self._rudder_angle)>5 then 
+            local turn_rate = math.rad(24)
+			newyaw = yaw + self.dtime*(1 - 1 / (math.abs(longit_speed) + 1)) * self._rudder_angle / 30 * turn_rate * trike.sign(longit_speed)
+		end
+
+        -- calculate energy consumption --
+        trike.consumptionCalc(self, accel)
+
+        --roll adjust
+        ---------------------------------
+		local sdir = minetest.yaw_to_dir(newyaw)
+		local snormal = {x=sdir.z,y=0,z=-sdir.x}	-- rightside, dot is negative
+		local prsr = trike.dot(snormal,nhdir)
+        local rollfactor = -20
+        newroll = (prsr*math.rad(rollfactor))*(later_speed)
+        --minetest.chat_send_all('newroll: '.. newroll)
+        ---------------------------------
+        -- end roll
+
+        -- pitch
+        newpitch = self._angle_of_attack/200 --(velocity.y * math.rad(6))
+
+        -- adjust pitch by velocity
+        local touching_ground, liquid_below = trike.check_node_below(self.object)
+        --self.isinliquid or 
+        if touching_ground then --isn't flying?
+            if newpitch < 0 then newpitch = 0 end
+
+            local min_speed = 4
+            if longit_speed < min_speed then
+                if newpitch > 0 then
+                    local percentage = ((longit_speed * 100)/min_speed)/100
+                    newpitch = newpitch * percentage
+                    if newpitch < 0 then newpitch = 0 end
+                end
+            end
+
+            --animate wheels
+            self.object:set_animation_frame_speed(longit_speed * 10)
+            self.wheel:set_animation_frame_speed(longit_speed * 10)
+        else
+            --stop wheels
+            self.object:set_animation_frame_speed(0)
+            self.wheel:set_animation_frame_speed(0)
+        end
+        
+        --adjust wing pitch (3d model)
+        self.wing:set_attach(self.object,'',{x=0,y=29,z=0},{x=-self._angle_of_attack,y=0,z=0})
+
+        --adjust power indicator
+        local power_indicator_angle = trike.get_gauge_angle(self._power_lever/10)
+	    self.power_gauge:set_attach(self.object,'',TRIKE_GAUGE_POWER_POSITION,{x=0,y=0,z=power_indicator_angle})
+
+        if accel ~= nil then
+            --lift calculation
+            accel.y = accel_y
+	        local wing_dir = mobkit.rot_to_dir({x=self._angle_of_attack/30,y=newyaw,z=newroll})
+            combined_acc = trike.getLiftAccel(self, velocity, accel, longit_speed, wing_dir)
+            -- end lift
+
+    		self.object:set_acceleration(combined_acc)
+        end
+
+		if newyaw~=yaw or newpitch~=pitch or newroll~=roll then
+            self.object:set_rotation({x=newpitch,y=newyaw,z=newroll})
+        end
+
+        --adjust climb indicator
+        local climb_rate = velocity.y * 1.5
+        if climb_rate > 5 then climb_rate = 5 end
+        if climb_rate < -5 then climb_rate = -5 end
+        --minetest.chat_send_all('rate '.. climb_rate)
+        local climb_angle = trike.get_gauge_angle(climb_rate)
+        self.climb_gauge:set_attach(self.object,'',TRIKE_GAUGE_CLIMBER_POSITION,{x=0,y=0,z=climb_angle})
+
+        --saves last velocy for collision detection (abrupt stop)
+        self.last_vel = self.object:get_velocity()
+	end,
+
+	on_punch = function(self, puncher, ttime, toolcaps, dir, damage)
+		if not puncher or not puncher:is_player() then
+			return
+		end
+		local name = puncher:get_player_name()
+        if self.owner and self.owner ~= name and self.owner ~= "" then return end
+        if self.owner == nil then
+            self.owner = name
+        end
+        	
+        if self.driver_name and self.driver_name ~= name then
+			-- do not allow other players to remove the object while there is a driver
+			return
+		end
+
+        local touching_ground, liquid_below = trike.check_node_below(self.object)
+        
+        local is_attached = false
+        if puncher:get_attach() == self.object then is_attached = true end
+
+        local itmstck=puncher:get_wielded_item()
+        local item_name = ""
+        if itmstck then item_name = itmstck:get_name() end
+
+        if is_attached == false then
+
+            if item_name == "biofuel:biofuel" and self._engine_running == false and self.owner == name then
+                --refuel
+                trike.loadFuel(self, puncher:get_player_name())
+                return
+            end
+
+            --repair
+            if item_name == "trike:repair_tool" and self._engine_running == false  then
+                if self.hp_max < 50 then
+                    local inventory_item = "default:steel_ingot"
+                    local inv = puncher:get_inventory()
+                    if inv:contains_item("main", inventory_item) then
+                        local stack = ItemStack(inventory_item .. " 1")
+                        local taken = inv:remove_item("main", stack)
+                        self.hp_max = self.hp_max + 10
+                        if self.hp_max > 50 then self.hp_max = 50 end
+                        trike.setText(self)
+                    end
+                end
+                return
+            end
+
+            -- deal with painting or destroying
+		    if itmstck then
+			    local _,indx = item_name:find('dye:')
+			    if indx then
+
+                    --lets paint!!!!
+				    local color = item_name:sub(indx+1)
+				    local colstr = trike.colors[color]
+                    --minetest.chat_send_all(color ..' '.. dump(colstr))
+				    if colstr then
+                        trike.paint(self, self.object, colstr, "trike_painting.png")
+                        trike.paint(self, self.wing, colstr, "trike_wing_color.png")
+					    itmstck:set_count(itmstck:get_count()-1)
+					    puncher:set_wielded_item(itmstck)
+				    end
+                    -- end painting
+
+			    else -- deal damage
+				    if not self.driver and toolcaps and toolcaps.damage_groups and toolcaps.damage_groups.fleshy and item_name ~= "biofuel:biofuel" then
+					    --mobkit.hurt(self,toolcaps.damage_groups.fleshy - 1)
+					    --mobkit.make_sound(self,'hit')
+                        self.hp_max = self.hp_max - 10
+                        minetest.sound_play("collision", {
+	                        object = self.object,
+	                        max_hear_distance = 5,
+	                        gain = 1.0,
+                            fade = 0.0,
+                            pitch = 1.0,
+                        })
+                        trike.setText(self)
+				    end
+			    end
+            end
+
+            if self.hp_max <= 0 then
+                trike.destroy(self)
+            end
+
+        end
+        
+	end,
+
+	on_rightclick = function(self, clicker)
+		if not clicker or not clicker:is_player() then
+			return
+		end
+
+        local name = clicker:get_player_name()
+
+        local can_access = true
+        if trike.restricted == "true" then
+            can_access = minetest.check_player_privs(clicker, {flight_licence=true})
+        end
+
+        if can_access then
+            if self.owner and self.owner ~= name and self.owner ~= "" then return end
+            if self.owner == "" then
+                self.owner = name
+            end
+
+		    if name == self.driver_name then
+                trike.setText(self)
+
+                self._engine_running = false
+
+			    -- driver clicked the object => driver gets off the vehicle
+			    self.driver_name = nil
+			    -- sound and animation
+                if self.sound_handle then
+                    minetest.sound_stop(self.sound_handle)
+                    self.sound_handle = nil
+                end
+			    
+			    self.engine:set_animation_frame_speed(0)
+
+                -- detach the player
+		        clicker:set_detach()
+		        player_api.player_attached[name] = nil
+		        clicker:set_eye_offset({x=0,y=0,z=0},{x=0,y=0,z=0})
+		        player_api.set_animation(clicker, "stand")
+		        self.driver = nil
+                self.object:set_acceleration(vector.multiply(trike.vector_up, -trike.gravity))
+            
+		    elseif not self.driver_name then
+                -- no driver => clicker is new driver
+                trike.attach(self, clicker)
+		    end
+        else
+            minetest.show_formspec(name, "trike:flightlicence",
+                "size[4,2]" ..
+                "label[0.0,0.0;Sorry ...]"..
+                "label[0.0,0.7;You need a flight licence to fly it.]" ..
+                "label[0.0,1.0;You must obtain it from server admin.]" ..
+                "button_exit[1.5,1.9;0.9,0.1;e;Exit]")
+        end
+	end,
+})

trike_fuel_management.lua

@@ -0,0 +1,45 @@
+function trike.loadFuel(self, player_name)
+    if self._energy < 9.5 then 
+        local player = minetest.get_player_by_name(player_name)
+        local inv = player:get_inventory()
+        local inventory_fuel = "biofuel:biofuel"
+
+        if inv:contains_item("main", inventory_fuel) then
+            local stack = ItemStack(inventory_fuel .. " 1")
+            local taken = inv:remove_item("main", stack)
+
+	        self._energy = self._energy + 1
+            if self._energy > 10 then self._energy = 10 end
+
+            local energy_indicator_angle = trike.get_gauge_angle(self._energy)
+            self.fuel_gauge:set_attach(self.object,'',TRIKE_GAUGE_FUEL_POSITION,{x=0,y=0,z=energy_indicator_angle})
+	    end
+    else
+        print("Full tank.")
+    end
+end
+
+function trike.consumptionCalc(self, accel)
+    if accel == nil then return end
+    if self._energy > 0 and self._engine_running and accel ~= nil then
+        local zero_reference = vector.new()
+        local acceleration = trike.get_hipotenuse_value(accel, zero_reference)
+        local consumed_power = self._power_lever/500000
+        --minetest.chat_send_all('consumed: '.. consumed_power)
+        self._energy = self._energy - consumed_power;
+
+        local energy_indicator_angle = trike.get_gauge_angle(self._energy)
+        if self.fuel_gauge:get_luaentity() then
+            self.fuel_gauge:set_attach(self.object,'',TRIKE_GAUGE_FUEL_POSITION,{x=0,y=0,z=energy_indicator_angle})
+        else
+            --in case it have lost the entity by some conflict
+            --self.fuel_gauge=minetest.add_entity(TRIKE_GAUGE_POINTER_POSITION,'trike:pointer')
+            --self.fuel_gauge:set_attach(self.object,'',TRIKE_GAUGE_FUEL_POSITION,{x=0,y=0,z=energy_indicator_angle})
+        end
+    end
+    if self._energy <= 0 and self._engine_running and accel ~= nil then
+        self._engine_running = false
+        if self.sound_handle then minetest.sound_stop(self.sound_handle) end
+	    self.engine:set_animation_frame_speed(0)
+    end
+end

trike_global_definitions.lua

@@ -0,0 +1,14 @@
+--
+-- constants
+--
+LONGIT_DRAG_FACTOR = 0.13*0.13
+LATER_DRAG_FACTOR = 2.0
+
+deg = math.deg
+abs = math.abs
+min = math.min
+
+TRIKE_GAUGE_FUEL_POSITION = {x=1.5,y=8.2,z=14.2}
+TRIKE_GAUGE_POWER_POSITION = {x=1.5,y=9.7,z=14.2}
+TRIKE_GAUGE_CLIMBER_POSITION = {x=-1.2,y=9.55,z=14.2}
+

trike_utilities.lua

@@ -0,0 +1,270 @@
+dofile(minetest.get_modpath("trike") .. DIR_DELIM .. "trike_global_definitions.lua")
+
+function trike.get_hipotenuse_value(point1, point2)
+    return math.sqrt((point1.x - point2.x) ^ 2 + (point1.y - point2.y) ^ 2 + (point1.z - point2.z) ^ 2)
+end
+
+function trike.dot(v1,v2)
+	return v1.x*v2.x+v1.y*v2.y+v1.z*v2.z
+end
+
+function trike.sign(n)
+	return n>=0 and 1 or -1
+end
+
+function trike.minmax(v,m)
+	return math.min(math.abs(v),m)*trike.sign(v)
+end
+
+--lift
+function trike.getLiftAccel(self, velocity, accel, longit_speed, hull_direction)
+    --lift calculations
+    -----------------------------------------------------------
+    local max_height = 1500
+    
+    local retval = accel
+    if longit_speed > 1.0 then
+        local angle_of_attack = (self._angle_of_attack) / 10
+        local lift = 4.8 --lift 5
+        local daoa = deg(angle_of_attack)
+
+    	local curr_pos = self.object:get_pos()
+        local curr_percent_height = (100 - ((curr_pos.y * 100) / max_height))/100 --to decrease the lift coefficient at hight altitudes
+
+	    local cross = vector.cross(hull_direction,velocity)
+	    local lift_dir = vector.normalize(vector.cross(hull_direction,cross))
+        local lift_coefficient = (0.24*abs(daoa)*(1/(0.025*daoa+3))^4*math.sign(angle_of_attack))*curr_percent_height
+        local lift_val = lift*(vector.length(velocity)^2)*lift_coefficient
+
+        --local lift_acc = vector.multiply(lift_dir,lift_val) --original, but with a lot of interferences in roll
+        local lift_acc = lift_dir
+        lift_acc.y = lift_acc.y * lift_val --multiply only the Y axis for lift
+
+        --gliding calcs (to increase speed)
+        if not self.isinliquid then --is flying?
+            if velocity.y < 0 then
+                local speed = math.abs(velocity.y/2) + 0.75
+                lift_acc=vector.add(lift_acc,vector.multiply(hull_direction,speed))
+            end
+        end
+
+        retval = vector.add(accel,lift_acc)
+
+    end
+    -----------------------------------------------------------
+    -- end lift
+    return retval
+end
+
+
+function trike.get_gauge_angle(value)
+    local angle = value * 18
+    angle = angle - 90
+    angle = angle * -1
+	return angle
+end
+
+-- attach player
+function trike.attach(self, player)
+    local name = player:get_player_name()
+    self.driver_name = name
+
+    -- temporary------
+    self.hp = 50 -- why? cause I can desist from destroy
+    ------------------
+
+    -- attach the driver
+    player:set_attach(self.object, "", {x = 0, y = 9, z = 2}, {x = 0, y = 0, z = 0})
+    player:set_eye_offset({x = 0, y = 3, z = 3}, {x = 0, y = 3, z = 10})
+    player_api.player_attached[name] = true
+    -- make the driver sit
+    minetest.after(0.2, function()
+        local player = minetest.get_player_by_name(name)
+        if player then
+	        player_api.set_animation(player, "sit")
+        end
+    end)
+    -- disable gravity
+    self.object:set_acceleration(vector.new())
+end
+
+--painting
+function trike.paint(self, object, colstr, search_string)
+    if colstr then
+        self._color = colstr
+        local entity = object:get_luaentity()
+        local l_textures = entity.initial_properties.textures
+        for _, texture in ipairs(l_textures) do
+            local i,indx = texture:find(search_string)
+            if indx then
+                l_textures[_] = search_string .."^[multiply:".. colstr
+            end
+        end
+        object:set_properties({textures=l_textures})
+    end
+end
+
+-- destroy the boat
+function trike.destroy(self)
+    if self.sound_handle then
+        minetest.sound_stop(self.sound_handle)
+        self.sound_handle = nil
+    end
+
+    if self.driver_name then
+        local player = minetest.get_player_by_name(self.driver_name)
+        -- detach the driver first (puncher must be driver)
+        player:set_detach()
+        player:set_eye_offset({x = 0, y = 0, z = 0}, {x = 0, y = 0, z = 0})
+        player_api.player_attached[self.driver_name] = nil
+        -- player should stand again
+        player_api.set_animation(player, "stand")
+        self.driver_name = nil
+    end
+
+    local pos = self.object:get_pos()
+    if self.fuel_gauge then self.fuel_gauge:remove() end
+    if self.power_gauge then self.power_gauge:remove() end
+    if self.climb_gauge then self.climb_gauge:remove() end
+    if self.engine then self.engine:remove() end
+    if self.wing then self.wing:remove() end
+    if self.wheel then self.wheel:remove() end
+
+    self.object:remove()
+
+    pos.y=pos.y+2
+    for i=1,4 do
+	    minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'wool:white')
+    end
+
+    for i=1,6 do
+	    minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'default:mese_crystal')
+    end
+
+    for i=1,3 do
+	    minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'default:steel_ingot')
+    end
+
+    --minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'trike:trike')
+
+    local total_biofuel = math.floor(self._energy) - 1
+    for i=0,total_biofuel do
+        minetest.add_item({x=pos.x+math.random()-0.5,y=pos.y,z=pos.z+math.random()-0.5},'biofuel:biofuel')
+    end
+end
+
+function trike.check_node_below(obj)
+    local pos_below = obj:get_pos()
+    if pos_below then
+        pos_below.y = pos_below.y - 0.1
+        local node_below = minetest.get_node(pos_below).name
+        local nodedef = minetest.registered_nodes[node_below]
+        local touching_ground = not nodedef or -- unknown nodes are solid
+		        nodedef.walkable or false
+        local liquid_below = not touching_ground and nodedef.liquidtype ~= "none"
+        return touching_ground, liquid_below
+    end
+    return nil, nil
+end
+
+function trike.checkAttach(self)
+    if self.owner then
+        local player = minetest.get_player_by_name(self.owner)
+        
+        if player then
+            local player_attach = player:get_attach()
+            if player_attach then
+                if player_attach == self.object then
+                    return true
+                end
+            end
+        end
+    end
+    return false
+end
+
+function trike.setText(self)
+    local properties = self.object:get_properties()
+    local formatted = string.format(
+       "%.2f", self.hp_max
+    )
+    if properties then
+        properties.infotext = "Nice ultralight trike of " .. self.owner .. ". Current hp: " .. formatted
+        self.object:set_properties(properties)
+    end
+end
+
+function trike.testImpact(self, velocity)
+    collision = false
+    if self.last_vel == nil then return end
+    local impact = abs(trike.get_hipotenuse_value(velocity, self.last_vel))
+    if impact > 1 then
+        --minetest.chat_send_all('impact: '.. impact .. ' - hp: ' .. self.hp_max)
+        local p = self.object:get_pos()
+		local nodeu = mobkit.nodeatpos(mobkit.pos_shift(p,{y=1}))
+		local noded = mobkit.nodeatpos(mobkit.pos_shift(p,{y=-1}))
+        local nodel = mobkit.nodeatpos(mobkit.pos_shift(p,{x=-1}))
+        local noder = mobkit.nodeatpos(mobkit.pos_shift(p,{x=1}))
+        local nodef = mobkit.nodeatpos(mobkit.pos_shift(p,{z=1}))
+        local nodeb = mobkit.nodeatpos(mobkit.pos_shift(p,{z=-1}))
+		if (nodeu and nodeu.drawtype ~= 'airlike') or
+            (noded and noded.drawtype ~= 'airlike') or
+            (nodef and nodef.drawtype ~= 'airlike') or 
+            (nodeb and nodeb.drawtype ~= 'airlike') or 
+            (noder and noder.drawtype ~= 'airlike') or 
+            (nodel and nodel.drawtype ~= 'airlike') then
+			collision = true
+		end
+    end
+    if collision then
+        local damage = impact
+        self.hp_max = self.hp_max - damage --subtract the impact value directly to hp meter
+        local curr_pos = self.object:get_pos()
+
+        if self.driver_name then
+            minetest.sound_play("collision", {
+                to_player = self.driver_name,
+                --pos = curr_pos,
+                --max_hear_distance = 5,
+                gain = 1.0,
+                fade = 0.0,
+                pitch = 1.0,
+            })
+
+            local player_name = self.driver_name
+            trike.setText(self)
+
+            --minetest.chat_send_all('damage: '.. damage .. ' - hp: ' .. self.hp_max)
+            if self.hp_max < 0 then --if acumulated damage is greater than 50, adieu
+                trike.destroy(self)   
+            end
+
+            local player = minetest.get_player_by_name(player_name)
+		    if player:get_hp() > 0 then
+			    player:set_hp(player:get_hp()-(damage/2))
+		    end
+        end
+
+    end
+end
+
+function trike.checkattachBug(self)
+    -- for some engine error the player can be detached from the submarine, so lets set him attached again
+    local can_stop = true
+    if self.owner and self.driver_name then
+        -- attach the driver again
+        local player = minetest.get_player_by_name(self.owner)
+        if player then
+            trike.attach(self, player)
+            can_stop = false
+        end
+    end
+
+    if can_stop then
+        --detach player
+        if self.sound_handle ~= nil then
+            minetest.sound_stop(self.sound_handle)
+            self.sound_handle = nil
+        end
+    end
+end