Noch mehr mods

mods/hot_air_balloons/movement.lua

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+--localize global functions
+local vector_new = vector.new
+local math_hypot = math.hypot
+local atan = math.atan
+local cos = math.cos
+local sin = math.sin
+local abs = math.abs
+local pi = math.pi
+local min = math.min
+
+--max speed settings
+local max_ballooning_vertical_speed = 1
+local max_ballooning_horizontal_speed = 3
+
+local function is_water_is_air(pos)
+	local node_name = minetest.get_node(pos).name
+	return minetest.get_item_group(node_name, "water") > 0,
+		node_name == "air"
+end
+local function get_vertical_acceleration(self)
+	local heat = self.heat
+	local vel_y = self.object:getvelocity().y
+	local acc_candidate = heat / 1000 - 0.5
+	
+	--enforce max speed
+	if vel_y > max_ballooning_vertical_speed
+		and acc_candidate * vel_y > 0
+	then
+		return 0
+	else
+		return acc_candidate
+	end
+end
+
+--if balloon is submerged
+local function float_up(self, vel)
+	self.submerged = true
+	vel.y = 1
+	return vel
+end
+
+local function swim(self, vel)
+	--allow controls, allow up
+	local pos = self.object:get_pos()
+	--keep y constant or rising
+	local acc_y = get_vertical_acceleration(self)
+	
+	if self.submerged or acc_y < 0
+	then
+		self.submerged = false
+		vel.y = 0
+		return 0, vel
+	else
+		return acc_y, vel
+	end
+end
+
+
+local tau = pi * 2
+--returns the radian equivalent of a in the range [0, tau)
+local function to_radian(a)
+	if a < 0
+	then
+		return to_radian(a + tau)
+	elseif a >= tau
+	then
+		return to_radian(a - tau)
+	else
+		return a
+	end
+end
+--decides which is the shortest way to rotate towards where the player is looking
+local function get_rotate_direction(a, b)
+	return to_radian(a - b) < to_radian(b - a)
+end
+
+--rotates the balloon towards where the player is looking
+local pi_192ths = pi / 192 --radians to turn each step
+local function rotate(self, player)
+	-- + pi so it finishes rotating when looking towards where the player is looking
+	local player_yaw = player:get_look_horizontal() + pi
+	local self_yaw = self.object:getyaw()
+	
+	if get_rotate_direction(player_yaw, self_yaw)
+	then
+		self.object:setyaw(to_radian(self_yaw - pi_192ths))
+	else
+		self.object:setyaw(to_radian(self_yaw + pi_192ths))
+	end
+end
+
+--takes wasd and turns it into a 2d vector
+local pi_halves = pi / 2
+function get_direction(right, left, up, down)
+	local inline, cross = 0, 0
+	local move = right or left or up or down
+	if left then cross = 1 end
+	if right then cross = cross - 1 end
+	if up then inline = 1	end
+	if down then inline = inline - 1 end
+	local arg
+	if inline < 0
+	then
+		return atan(cross / inline) + pi, move
+	elseif inline > 0
+	then
+		return atan(cross / inline), move
+	else
+		return pi_halves * cross, move
+	end
+end
+
+
+--[[
+space to rotate where the player is looking
+wasd to apply acceleration
+shift to let out hot air, cooling the balloon
+]]
+local function handle_control(self, vel)
+	if not self.pilot
+	then
+		return 0, 0
+	end
+	local player = minetest.get_player_by_name(self.pilot)
+	if not player --player left, balloon should get deleted
+	then
+		return 0, 0
+	end
+	local control = player:get_player_control()
+	if control.sneak --lowering heat quickly
+	then
+		local heat = self.heat - 30
+		if heat < 0
+		then
+			self.heat = 0
+		else
+			self.heat = heat
+		end
+	end
+	
+	if control.jump --rotate towards player yaw
+	then
+		rotate(self, player)
+	end
+	
+	--taking direction from get_direction
+	--and turning it into radians.
+	--if max speed is reached, only acceleration in the opposite direction is applied.
+	local dir_radians, move = get_direction(control.right, control.left, control.up, control.down)
+	if move and math_hypot(vel.x, vel.z)
+	then
+		dir_radians = dir_radians + player:get_look_horizontal()
+		local x, z = -sin(dir_radians), cos(dir_radians)
+		if math_hypot(vel.x, vel.z) > max_ballooning_horizontal_speed
+		then
+			if x * vel.x > 0
+			then
+				x = 0
+			end
+			if z * vel.z > 0
+			then
+				z = 0
+			end
+		end
+		return x, z
+	end
+	return 0, 0
+end
+
+--[[handle movement in different cases
+movement restrictions:
+	-on ground: only vertical movement
+	-on water: free movement, though vertical only if up
+	-submerged: free movement, vertical goes up automatically
+	-in air: completely free movement
+]]
+
+return function(self)
+	local pos_in = self.object:get_pos()
+	local pos_under = vector_new(pos_in.x, pos_in.y - 0.1, pos_in.z)
+	local on_water, in_air = is_water_is_air(pos_under)
+	local acc = vector_new(0, 0, 0)
+	local vel = self.object:getvelocity()
+	
+	
+	if is_water_is_air(pos_in) --if submerged
+	then
+		vel = float_up(self, vel)
+		acc.x, acc.z = handle_control(self, vel)
+		self.object:setvelocity(vel)
+	elseif on_water --if on water
+	then
+		acc.y, vel = swim(self, vel)
+		self.object:setvelocity(vel)
+		acc.x, acc.z = handle_control(self, vel)
+	elseif in_air
+	then
+		--allow controls and height change
+		acc.y = get_vertical_acceleration(self)
+		acc.x, acc.z = handle_control(self, vel)
+	else --if on ground
+		--only allow height change
+		acc.y = get_vertical_acceleration(self)
+		vel.x = 0
+		vel.z = 0
+		self.object:setvelocity(vel)
+	end
+	self.object:setacceleration(acc)
+end