Initial commit with working proof-of-concept.

.luacheckrc

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+globals = {"minetest", "ItemStack", "VoxelArea", "vector", "nodecore", "include", "SecureRandom"}
+color = false
+quiet = 1

.lualocals

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+~print
+minetest
+ItemStack
+VoxelArea

api.lua

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+-- LUALOCALS < ---------------------------------------------------------
+local math, minetest
+    = math, minetest
+local math_floor, math_min, math_random
+    = math.floor, math.min, math.random
+-- LUALOCALS > ---------------------------------------------------------
+
+local modname = minetest.get_current_modname()
+
+local spawners = {}
+
+local function calc_scalar(params, def)
+	if not def then return 0 end
+	local total = 0
+	for i = 1, math_min(#params, #def) do
+		total = total + params[i] * def[i]
+	end
+	return total
+end
+
+local function calc_vector(params, def)
+	if not def then return {x = 0, y = 0, z = 0} end
+	return {
+		x = calc_scalar(params, def.x),
+		y = calc_scalar(params, def.y),
+		z = calc_scalar(params, def.z)
+	}
+end
+
+local function spawn(def, pnum)
+	local params = {1, pnum / def.amount}
+	for _ = 1, 12 do params[#params + 1] = math_random() end
+	minetest.add_particle({
+			pos = calc_vector(params, def.pos),
+			velocity = calc_vector(params, def.velocity),
+			acceleration = calc_vector(params, def.acceleration),
+			expirationtime = calc_scalar(params, def.expirationtime),
+			size = calc_scalar(params, def.size),
+			glow = calc_scalar(params, def.glow),
+			collisiondetection = def.collisiondetection,
+			collision_removal = def.collision_removal,
+			object_collision = def.object_collision,
+			vertical = def.vertical,
+			texture = def.texture,
+			playername = def.playername,
+			animation = def.animation
+		})
+end
+
+minetest.register_entity(modname .. ":spawner", {
+		initial_properties = {
+			physical = false,
+			collide_with_objects = false,
+			collisionbox = {0, 0, 0, 0, 0, 0},
+			visual_size = {x = 0, y = 0},
+			is_visible = false,
+			static_save = false
+		},
+		on_activate = function(self, data)
+			if not data then return self.object:remove() end
+			data = minetest.deserialize(data)
+			self.id = data.id
+			self.def = data.def
+			self.age = 0
+			if self.def.time <= 0 then -- corner case
+				for i = 1, self.def.amount do spawn(self.def, i) end
+				spawners[self.id] = nil
+				return self.object:remove()
+			end
+		end,
+		on_step = function(self, dtime)
+			local start = self.age
+			self.age = self.age + dtime
+			if self.age > self.def.time then self.age = self.def.time end
+
+			local pstart = math_floor(self.def.amount * start / self.def.time)
+			local pend = math_floor(self.def.amount * self.age / self.def.time)
+			for i = pstart + 1, pend do spawn(self.def, i) end
+
+			if self.age >= self.def.time then
+				spawners[self.id] = nil
+				return self.object:remove()
+			end
+		end
+	})
+
+minetest.add_particlespawner_advanced = minetest.add_particlespawner_advanced or function(def)
+	local params = {1, 0.5}
+	for _ = 1, 12 do params[#params + 1] = 0.5 end
+	local pos = calc_vector(params, def.pos)
+	local id = #spawners + 1
+	local obj = minetest.add_entity(pos, modname .. ":spawner",
+		minetest.serialize({id = id, def = def}))
+	if not obj then return end
+	spawners[id] = obj
+	return id
+end
+
+minetest.delete_particlespawner_advanced = minetest.delete_particlespawner_advanced or function(id)
+	if not id then return end
+	local obj = spawners[id]
+	if not obj then return end
+	obj:remove()
+	spawners[id] = nil
+end

demo.lua

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+-- LUALOCALS < ---------------------------------------------------------
+local math, minetest
+    = math, minetest
+local math_random
+    = math.random
+-- LUALOCALS > ---------------------------------------------------------
+
+local modname = minetest.get_current_modname()
+
+local blackdot = "[combine:1x1^[noalpha"
+local bdesc = blackdot:gsub("%^", "\\^"):gsub(":", "\\:")
+local frame = "[combine:16x16:0,0=" .. bdesc .. ":15,0=" .. bdesc
+.. ":0,15=" .. bdesc .. ":15,15=" .. bdesc
+
+local function regdemo(num, func)
+	return minetest.register_node(modname .. ":demo" .. num, {
+			drawtype = "allfaces",
+			tiles = {{name = frame, backface_culling = false}},
+			groups = {[modname] = 1},
+			on_punch = function(pos) return minetest.remove_node(pos) end,
+			on_demo = func
+		})
+end
+
+minetest.register_abm({
+		nodenames = {"group:" .. modname},
+		interval = 2,
+		chance = 1,
+		action = function(pos, node)
+			local def = minetest.registered_nodes[node.name]
+			if def and def.on_demo then return def.on_demo(pos, node) end
+		end
+	})
+
+regdemo(1, function(pos)
+		local endpos = {
+			x = pos.x + math_random() * 20 - 10,
+			y = pos.y + math_random() * 20 - 10,
+			z = pos.z + math_random() * 20 - 10,
+		}
+		minetest.add_particlespawner_advanced({
+				amount = 25,
+				time = 0.25,
+				pos = {
+					x = {pos.x, endpos.x - pos.x},
+					y = {pos.y, endpos.y - pos.y},
+					z = {pos.z, endpos.z - pos.z}
+				},
+				velocity = {
+					x = {(endpos.x - pos.x) / 2, -(endpos.x - pos.x) / 2},
+					y = {(endpos.y - pos.y) / 2, -(endpos.y - pos.y) / 2},
+					z = {(endpos.z - pos.z) / 2, -(endpos.z - pos.z) / 2}
+				},
+				expirationtime = {2, -0.25},
+				texture = blackdot,
+				size = {1, 4}
+			})
+	end)
+
+regdemo(2, function(pos)
+		minetest.add_particlespawner_advanced({
+				amount = 25,
+				time = 0,
+				pos = {
+					x = {pos.x, -10, 20},
+					y = {pos.y, -10, 0, 20},
+					z = {pos.z, -10, 0, 0, 20}
+				},
+				velocity = {
+					x = {0, 20, -40},
+					y = {0, 20, 0, -40},
+					z = {0, 20, 0, 0, -40}
+				},
+				acceleration = {
+					x = {0, -20, 40},
+					y = {0, -20, 0, 40},
+					z = {0, -20, 0, 0, 40}
+				},
+				expirationtime = {1},
+				texture = blackdot,
+				size = {1, 0, 0, 0, 0, 4}
+			})
+	end)

init.lua

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+-- LUALOCALS < ---------------------------------------------------------
+local dofile, minetest
+    = dofile, minetest
+-- LUALOCALS > ---------------------------------------------------------
+
+local modname = minetest.get_current_modname()
+local modpath = minetest.get_modpath(modname)
+
+dofile(modpath .. "/api.lua")
+dofile(modpath .. "/demo.lua")