demo/src/StarterPlayer/StarterPlayerScripts/systems/lol.luau

@@ -1,67 +0,0 @@
---!optimize 2
---!native
---!strict
-
-local ReplicatedStorage = game:GetService("ReplicatedStorage")
-local jecs = require(ReplicatedStorage.ecs)
-local __ = jecs.Wildcard
-local std = ReplicatedStorage.std
-
-local world = require(std.world)
-
-local Position = world:component() :: jecs.Entity<vector>
-local Previous = jecs.Rest
-local pre = jecs.pair(Position, Previous)
-
-local added = world
-	:query(Position)
-	:without(pre)
-	:cached()
-local changed = world
-	:query(Position, pre)
-	:cached()
-local removed = world
-	:query(pre)
-	:without(Position)
-	:cached()
-
-local children = {}
-for i = 1, 10 do
-	local e = world:entity()
-	world:set(e, Position, vector.create(i, i, i))
-	table.insert(children, e)
-end
-local function flip()
-	return math.random() > 0.5
-end
-local function system()
-	for i, child in children do
-		world:set(child, Position, vector.create(i,i,i))
-	end
-	for e, p in added:iter() do
-		world:set(e, pre, p)
-	end
-	for i, child in children do
-		if flip() then
-			world:set(child, Position, vector.create(i + 1, i + 1, i + 1))
-		end
-	end
-	for e, new, old in changed:iter() do
-		if new ~= old then
-			world:set(e, pre, new)
-		end
-	end
-
-	for i, child in children do
-		world:remove(child, Position)
-	end
-
-	for e in removed:iter() do
-		world:remove(e, pre)
-	end
-end
-local scheduler = require(std.scheduler)
-
-scheduler.SYSTEM(system)
-
-return 0

demo/src/StarterPlayer/StarterPlayerScripts/systems/lol2.luau

@@ -1,90 +0,0 @@
---!optimize 2
---!native
---!strict
-
-local ReplicatedStorage = game:GetService("ReplicatedStorage")
-local jecs = require(ReplicatedStorage.ecs)
-local __ = jecs.Wildcard
-local std = ReplicatedStorage.std
-
-local world = require(std.world)
-
-local Position = world:component() :: jecs.Entity<vector>
-local Previous = jecs.Rest
-local pre = jecs.pair(Position, Previous)
-
-local added = world
-	:query(Position)
-	:without(pre)
-	:cached()
-local changed = world
-	:query(Position, pre)
-	:cached()
-local removed = world
-	:query(pre)
-	:without(Position)
-	:cached()
-
-local children = {}
-for i = 1, 10 do
-	local e = world:entity()
-	world:set(e, Position, vector.create(i, i, i))
-	table.insert(children, e)
-end
-local function flip()
-	return math.random() > 0.5
-end
-local entity_index = world.entity_index
-local function copy(archetypes, id)
-	for _, archetype in archetypes do
-
-		local to = jecs.archetype_traverse_add(world, pre, archetype)
-		local columns = to.columns
-		local records = to.records
-		local old = columns[records[pre].column]
-		local new =	columns[records[id].column]
-
-		if to ~= archetype then
-			for _, entity in archetype.entities do
-				local r = jecs.entity_index_try_get_fast(entity_index, entity)
-				jecs.entity_move(entity_index, entity, r, to)
-			end
-		end
-
-		table.move(new, 1, #new, 1, old)
-
-	end
-end
-local function system2()
-	for i, child in children do
-		world:set(child, Position, vector.create(i,i,i))
-	end
-	for e, p in added:iter() do
-	end
-	copy(added:archetypes(), Position)
-	for i, child in children do
-		if flip() then
-			world:set(child, Position, vector.create(i + 1, i + 1, i + 1))
-		end
-	end
-
-	for e, new, old in changed:iter() do
-		if new ~= old then
-		end
-	end
-
-	copy(changed:archetypes(), Position)
-
-	for i, child in children do
-		world:remove(child, Position)
-	end
-
-	for e in removed:iter() do
-		world:remove(e, pre)
-	end
-end
-local scheduler = require(std.scheduler)
-
-scheduler.SYSTEM(system2)
-
-return 0

demo/src/StarterPlayer/StarterPlayerScripts/systems/move.luau

@@ -9,23 +9,15 @@ local cts = require(std.components)
 local Model = cts.Model
 local Transform = cts.Transform
 
-local moved_models = world:query(Model, Transform):cached()
+local moving_models = world:query(Transform, Model):cached()
-local updated_models = {}
-local i = 0
-local function processed(n)
-	i += 1
-	if i > n then
-		i = 0
-		return true
-	end
-	return false
-end
-
 local function move(dt: number)
-	for entity, model in moved_models do
+	for _, transform, model in moving_models do
-		if updated_models[entity] then
+		local cf = transform.new
-			updated_models[entity] = nil
+		if cf ~= transform.old then
-			model.PrimaryPart.CFrame = transform
+			local part = model.PrimaryPart :: BasePart
+			local origo = part.CFrame
+			part.CFrame = origo:Lerp(cf, 1)
+			transform.old = cf
 		end
 	end
 end
@@ -33,8 +25,11 @@ end
 local function syncTransforms()
 	for _, id, cf in blink.UpdateTransform.Iter() do
 		local e = ref("server-" .. tostring(id))
-		world:set(e, Transform, cf)
+		local transform = world:get(e, Transform)
-		moved_models[e] = true
+		if not transform then
+			continue
+		end
+		transform.new = cf
 	end
 end
 
@@ -43,4 +38,4 @@ local scheduler = require(std.scheduler)
 scheduler.SYSTEM(move)
 scheduler.SYSTEM(syncTransforms)
 
-return 0
+return 0

examples/luau/queries/changetracking.luau

@@ -1,5 +1,4 @@
 local jecs = require("@jecs")
-local pair = jecs.pair
 
 local world = jecs.World.new()
 local Name = world:component()
@@ -13,37 +12,39 @@ local function name(e)
 	return world:get(e, Name)
 end
 
-local Position = named(world.component, "Position") :: jecs.Entity<vector>
+local Position = named(world.component, "Position") :: jecs.Entity<Vector3>
 local Previous = jecs.Rest
+local PreviousPosition = jecs.pair(Previous, Position)
 
 local added = world
 	:query(Position)
-	:without(pair(Previous, Position))
+	:without(PreviousPosition)
 	:cached()
 local changed = world
-	:query(Position, pair(Previous, Position))
+	:query(Position, PreviousPosition)
 	:cached()
 local removed = world
-	:query(pair(Previous, Position))
+	:query(PreviousPosition)
 	:without(Position)
 	:cached()
 
-
 local e1 = named(world.entity, "e1")
-world:set(e1, Position, vector.create(10, 20, 30))
+world:set(e1, Position, Vector3.new(10, 20, 30))
+
 local e2 = named(world.entity, "e2")
-world:set(e2, Position, vector.create(10, 20, 30))
+world:set(e2, Position, Vector3.new(10, 20, 30))
-for entity, p in added do
+
-	print(`Added {name(entity)}: \{{p.x}, {p.y}, {p.z}}`)
+for e, p in added:iter() do
-	world:set(entity, pair(Previous, Position), p)
+	print(`Added {e}: \{{p.X}, {p.Y}, {p.Z}}`)
+	world:set(e, PreviousPosition, p)
 end
 
-world:set(e1, Position, vector.create(999, 999, 1998))
+world:set(e1, Position, "")
 
-for _, archetype in changed:archetypes() do
+for e, new, old in changed:iter() do
 	if new ~= old then
-		print(`{name(e)}'s Position changed from \{{old.x}, {old.y}, {old.z}\} to \{{new.x}, {new.y}, {new.z}\}`)
+		print(`{name(new)}'s Position changed from \{{old.X}, {old.Y}, {old.Z}\} to \{{new.X}, {new.Y}, {new.Z}\}`)
-		world:set(e, pair(Previous, Position), new)
+		world:set(e, PreviousPosition, new)
 	end
 end
 
@@ -51,7 +52,6 @@ world:remove(e2, Position)
 
 for e in removed:iter() do
 	print(`Position was removed from {name(e)}`)
-	world:remove(e, pair(Previous, Position))
 end
 
 -- Output:

jecs.luau

@@ -1144,9 +1144,6 @@ do
 			end
 		end
 
-		local sparse_array = entity_index.sparse_array
-		local dense_array = entity_index.dense_array
-
 		if idr_t then
 			for archetype_id in idr_t.cache do
 				local children = {}
@@ -1177,14 +1174,24 @@ do
 						else
 							local on_remove = id_record.hooks.on_remove
 							local to = archetype_traverse_remove(world, id, idr_t_archetype)
-							local empty = #to.types == 0
+							if on_remove then
-							for i = n, 1, -1 do
+								if to then
-								local child = children[i]
+									for i = n, 1, -1 do
-								if on_remove then
+										local child = children[i]
-									on_remove(child)
+										on_remove(children[i])
+										local r = entity_index_try_get_fast(entity_index, child) :: Record
+										entity_move(entity_index, child, r, to)
+									end
+								else
+									for i = n, 1, -1 do
+										local child = children[i]
+										on_remove(child)
+									end
 								end
-								local r = sparse_array[ECS_ENTITY_T_LO(child)]
+							elseif to then
-								if not empty then
+								for i = n, 1, -1 do
+									local child = children[i]
+									local r = entity_index_try_get_fast(entity_index, child) :: Record
 									entity_move(entity_index, child, r, to)
 								end
 							end
@@ -1196,6 +1203,7 @@ do
 			end
 		end
 
+		local dense_array = entity_index.dense_array
 		local index_of_deleted_entity = record.dense
 		local index_of_last_alive_entity = entity_index.alive_count
 		entity_index.alive_count = index_of_last_alive_entity - 1
@@ -2188,7 +2196,7 @@ function World.new()
 	return self
 end
 
-export type Entity<T = unknown> = {__T: T}
+export type Entity<T = nil> = number & { __T: T }
 
 export type Id<T = nil> =
     | Entity<T>
@@ -2354,8 +2362,6 @@ return {
 	archetype_traverse_add = archetype_traverse_add,
 	archetype_traverse_remove = archetype_traverse_remove,
 
-	entity_move = entity_move,
-
 	entity_index_try_get = entity_index_try_get,
 	entity_index_try_get_any = entity_index_try_get_any,
 	entity_index_try_get_fast = entity_index_try_get_fast,

test/tests.luau

@@ -1045,21 +1045,6 @@ TEST("world:component()", function()
 end)
 
 TEST("world:delete", function()
-	do CASE "delete recycled entity id used as component"
-		local world = world_new()
-		local id = world:entity()
-		world:add(id, jecs.Component)
-
-		local e = world:entity()
-		world:set(e, id, 1)
-		CHECK(world:get(e, id) == 1)
-		world:delete(id)
-		local recycled = world:entity()
-		world:add(recycled, jecs.Component)
-		world:set(e, recycled, 1)
-		CHECK(world:has(recycled, jecs.Component))
-		CHECK(world:get(e, recycled) == 1)
-	end
 	do
 		CASE("bug: Empty entity does not respect cleanup policy")
 		local world = world_new()