at least a bit history

nether/pearl.lua

@@ -0,0 +1,114 @@
+local function table_contains(t, v)
+	for _,i in pairs(t) do
+		if v == i then
+			return true
+		end
+	end
+	return false
+end
+
+local teleportball_player
+local function throw_pearl(item, player)
+	local playerpos = player:getpos()
+	local obj = minetest.add_entity({x=playerpos.x,y=playerpos.y+1.625,z=playerpos.z}, "nether:pearl_entity")
+	local dir = player:get_look_dir()
+	obj:setvelocity({x=dir.x*30, y=dir.y*30, z=dir.z*30})
+	obj:setacceleration({x=dir.x*-3, y=-dir.y^8*80-10, z=dir.z*-3})
+	if not minetest.setting_getbool("creative_mode") then
+		item:take_item()
+	end
+	teleportball_player = player
+	return item
+end
+
+local ENTITY = {
+	timer=0,
+	collisionbox = {0,0,0,0,0,0}, --not pointable
+	physical = false, -- Collides with things
+	textures = {"nether_pearl.png"},
+	lastpos={},
+	player = "",
+}
+
+local allowed_nodes = {"air", "default:water_source"}
+local function teleport_player(pos, player)
+	local nd2 = minetest.get_node(pos).name
+	pos.y = pos.y+1
+	local nd3 = minetest.get_node(pos).name
+	if table_contains(allowed_nodes, nd2)
+	and table_contains(allowed_nodes, nd3) then
+		pos.y = pos.y-1.4
+		player:moveto(pos)
+		pos.y = pos.y-0.6
+		return true
+	end
+	return false
+end
+
+ENTITY.on_step = function(self, dtime)
+	self.timer=self.timer+dtime
+
+--[[	local delay = self.delay
+	if delay < 0.1 then
+		self.delay = delay+dtime
+		return
+	end
+	self.delay = 0]]
+	local pos = self.object:getpos()
+	local lastpos = self.lastpos
+	if lastpos.x
+	and vector.equals(vector.round(lastpos), vector.round(pos)) then
+		return
+	end
+	local player = self.player
+	if not player
+	or player == "" then
+		self.player = teleportball_player
+		player = teleportball_player
+	end
+	if not player then
+		self.object:remove()
+		return
+	end
+	if lastpos.x then --If there is no lastpos for some reason.
+		local free, p = minetest.line_of_sight(lastpos, pos)
+		if not free then
+			local nd1 = minetest.get_node(p).name
+			if not table_contains(allowed_nodes, nd1)
+			and nd1 ~= "ignore" then
+				self.object:remove()
+				minetest.after(0, function(p) --minetest.after us used that the sound is played after the teleportation
+					minetest.sound_play("nether_pearl", {pos=p, max_hear_distance=10})
+				end, p)
+				p.y = p.y+1
+				if teleport_player(p, player) then
+					return
+				end
+				p.y = p.y-2
+				for i = -1,1,2 do
+					for _,j in pairs({{i, 0}, {0, i}}) do
+						if teleport_player({x=p.x+j[1], y=p.y, z=p.z+j[2]}, player) then
+							return
+						end
+					end
+				end
+				for i = -1,1,2 do
+					for j = -1,1,2 do
+						if teleport_player({x=p.x+j, y=p.y, z=p.z+i}, player) then
+							return
+						end
+					end
+				end
+			end
+		end
+	end
+	if self.timer > 20 then
+		self.object:remove()
+		return
+	end
+	self.lastpos = vector.new(pos)
+end
+
+minetest.register_entity("nether:pearl_entity", ENTITY)
+
+minetest.override_item("nether:pearl", {on_use = throw_pearl})