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ecs overhaul part 2

Various improvements made as they were needed:
* only gives the entity system table as argument in callback as that's the only thing needed most of the time
* to access the entity, a .entity field in now defined in every entity system table
* filter use ecs.any when given a table; allow booleans for always/never filter
* removed .m table from entity
* added ability to define methods on entities system table directly; allows to re-implement previous .m functionality (will provide some example systems in a later commit)
This commit is contained in:
Étienne Fildadut 2021-04-13 01:35:43 +02:00
parent cc0ed18eb3
commit f607058753

View file

@ -36,17 +36,6 @@ let recCallOnRemoveFromWorld = (world, systems)
end
end
--- Recursively get a list of systems with a certain method.
let recGetSystemsWithMethod = (method, systems, l={})
for _, s in ipairs(systems) do
if s[method] then
table.insert(l, s)
end
recGetSystemsWithMethod(method, s.systems, l)
end
return l
end
--- Iterate through the next entity, based on state s: { previousLinkedListItem }
let nextEntity = (s)
if s[1] then
@ -58,7 +47,7 @@ let nextEntity = (s)
end
end
--- Recursively content of a into b if it isn't already present. No cycle detection.
--- Recursively copy content of a into b if it isn't already present. No cycle detection.
let copy = (a, b)
for k, v in pairs(a) do
if type(v) == "table" then
@ -78,31 +67,36 @@ end
-- When they are added to a world, a new, per-world self table is created and used for every method call (which we call "instancied system").
-- Instancied systems can be retrieved in system.s or system.systems.
-- Oh, the "world" is just the top-level system, behaving in exactly the same way as other systems.
-- Every field defined below is optional.
let system_mt = {
--- Read-only after creation system options ---
-- I mean, you can try to change them afterwards. But, heh.
--- Name of the system (optional).
-- Used to create a field with the system's name in world.s.
-- Used to create a field with the system's name in world.s and into each entity (the "entity's system table").
name = nil,
--- List of subsystems.
-- On a instancied system, this is a list of the same subsystems, but instancied for this world.
systems = nil,
--- Modifiable system options ---
--- Returns true if the entity should be added to this system (and therefore its subsystems).
-- If this is a string or a table, it will be converted to a filter function on instanciation using ecs.all.
-- If this is a string or a table, it will be converted to a filter function on instanciation using ecs.any.
-- If this true, will accept every entity; if false, reject every entity.
-- Will only test entities when they are added; changing this after system creation will not affect entities already in the system.
-- By default, rejects everything.
filter = :(e) return false end,
--- Returns true if e1 <= e2.
-- Used to place the entity in the sorted entity list when it is added; changing this after system creation
-- will not change the order of entities already in the system.
compare = :(e1, e2) return true end,
--- Modifiable system options ---
--- Called when adding an entity to the system.
onAdd = :(s, e) end,
onAdd = :(s) end,
--- Called when removing an entity from the system.
onRemove = :(s, e) end,
onRemove = :(s) end,
--- Called when the system is instancied, before any call to :onnAddToWorld (including other systems in the world).
onInstance = :() end,
--- Called when the system is added to a world.
@ -116,9 +110,9 @@ let system_mt = {
--- Called when drawing the system.
onDraw = :() end,
--- Called when updating the system, for every entity the system contains. Called after :onUpdate was called on the system.
process = :(s, e, dt) end,
process = :(s, dt) end,
--- Called when drawing the system, for every entity the system contains. Called after :onDraw was called on the system.
render = :(s, e) end,
render = :(s) end,
--- If not false, the system will only update every interval seconds.
interval = false,
@ -128,7 +122,14 @@ let system_mt = {
visible = true,
--- Defaults value to put into the entities's system table when they are added. Will recursively fill missing values.
-- When an entity is added to a system, a .entity field is created in the system table, referring to the full entity table.
-- Changing this will not affect entities already in the system.
default = nil,
--- Defaults methods to assign to the entities's system table when they are added.
-- When calling the methods with entity.systemName:method(...), the method will actually receive the
-- arguments method(system, entity system table, ...). Methamethods are accepted. New methods can be
-- created anytime.
methods = nil,
--- Read-only system options ---
@ -148,8 +149,10 @@ let system_mt = {
_previous = nil,
--- Amount of time waited since last update (if interval is set).
_waited = 0,
--- Metatable of entities' m method table. Same for every system from the same world.
_entity_m_mt = nil,
--- Metatable of entities' system table.
-- Contains the methods defined in the methods field, wrapped to be called with the correct arguments, as well as a
-- __index field (if not redefined in methods).
_methods_mt = nil,
--- Methods ---
@ -159,11 +162,15 @@ let system_mt = {
-- If this is called on a subsystem instead of the world, be warned that this will bypass all the parent's systems filters.
-- Since :remove will not search for entities in systems where they should have been filtered out, the added entities will not be removed
-- when calling :remove on a parent system or the world. The entity can be removed by calling :remove on the system :add was called on.
-- Complexity: O(1) per unordered system, O(entityCount) per ordered system.
add = :(e, ...)
if e ~= nil and not @_previous[e] and @filter(e) then
-- setup entity
if not e.m then
e.m = setmetatable({ _entity = e }, @_entity_m_mt)
if @name then
if not e[@name] e[@name] = {}
if @default copy(@default, e[@name])
if @methods setmetatable(e[@name], @_methods_mt)
e[@name].entity = e
end
-- add to linked list
if @_first == nil then
@ -193,8 +200,7 @@ let system_mt = {
end
-- notify addition
@entityCount += 1
if (@default and e[@name]) copy(@default, e[@name])
@onAdd(e[@name], e)
@onAdd(e[@name])
-- add to subsystems
for _, s in ipairs(@systems) do
s:add(e)
@ -209,6 +215,7 @@ let system_mt = {
--- Refresh an entity's systems.
-- Behave similarly to :add, but if the entity is already in the system, instead of skipping it, it
-- will check for new and removed components and add and remove from (sub)systems accordingly.
-- Complexity: O(1) per system + add/remove complexity.
refresh = :(e, ...)
if e ~= nil then
if not @_previous[e] then
@ -234,6 +241,7 @@ let system_mt = {
-- Entities are removed from subsystems before they are removed from their parent system.
-- If you intend to call this on a subsystem instead of the world, please read the warning in :add.
-- Returns all removed entities.
-- Complexity: O(1) per system.
remove = :(e, ...)
if e ~= nil and @_previous[e] then
-- remove from subsystems
@ -256,7 +264,7 @@ let system_mt = {
-- notify removal
@_previous[e] = nil
@entityCount -= 1
@onRemove(e[@name], e)
@onRemove(e[@name])
end
if ... then
return e, @remove(...)
@ -265,6 +273,7 @@ let system_mt = {
end
end,
--- Returns true if every entity is in the system.
-- Complexity: O(1).
has = :(e, ...)
let has = e == nil or not not @_previous[e]
if ... then
@ -299,14 +308,14 @@ let system_mt = {
@onUpdate(dt)
if @process ~= system_mt.process then
for e in @iter() do
@process(e[@name], e, dt)
@process(e[@name], dt)
end
end
for _, s in ipairs(@systems) do
s:update(dt)
end
if @interval then
@_waited = 0
@_waited -= @interval
end
end
end,
@ -317,7 +326,7 @@ let system_mt = {
@onDraw()
if @render ~= system_mt.render then
for e in @iter() do
@render(e[@name], e)
@render(e[@name])
end
end
for _, s in ipairs(@systems) do
@ -332,18 +341,42 @@ let system_mt = {
end
}
--- Self descriptive
let alwaysTrue = () return true end
let alwaysFalse = () return true end
--- Recursively instanciate a list of systems for a world:
-- * create their self table with instance fields set
-- * create a field with their name in world.s (if name defined)
let recInstanciateSystems = (world, systems)
let t = {}
for _, s in ipairs(systems) do
table.insert(t, setmetatable({
let system
-- setup method table
let methods_mt = {}
if s.methods then
methods_mt.__index = methods_mt
for k, v in pairs(s.methods) do
methods_mt[k] = :(...)
return v(system, @, ...)
end
end
setmetatable(s.methods, {
__newindex = :(k, v)
rawset(@, k, v)
methods_mt[k] = :(...)
return v(system, @, ...)
end
end
})
end
-- instanciate system
system = setmetatable({
systems = recInstanciateSystems(world, s.systems or {}),
world = world,
s = world.s,
_previous = {},
_entity_m_mt = world._entity_m_mt
_methods_mt = methods_mt
}, {
__index = :(k)
if s[k] ~= nil then
@ -352,13 +385,20 @@ let recInstanciateSystems = (world, systems)
return system_mt[k]
end
end
}))
let system = t[#t]
})
if type(s.filter) == "string" then
system.filter = (_, e) return e[s.filter] ~= nil end
elseif type(s.filter) == "table" then
system.filter = ecs.all(unpack(s.filter))
system.filter = ecs.any(unpack(s.filter))
elseif type(s.filter) == "boolean" then
if s.filter then
system.filter = alwaysTrue
else
system.filter = alwaysFalse
end
end
-- add system
table.insert(t, system)
if s.name then
world.s[s.name] = system
end
@ -374,10 +414,6 @@ let recCallOnAddToWorld = (world, systems)
end
end
--- Self descriptive
let alwaysTrue = () return true end
let alwaysFalse = () return true end
--- ECS module.
ecs = {
--- Create and returns a world system based on a list of systems.
@ -387,30 +423,8 @@ ecs = {
let world = setmetatable({
filter = ecs.all(),
s = {},
_previous = {},
_entity_m_mt = setmetatable({}, {
__index = (_entity_m_mt, k)
let s = recGetSystemsWithMethod(k, {world})
_entity_m_mt[k] = (m, ...)
let e = m._entity
let args = {...}
for _, sys in ipairs(s) do
if sys._previous[e] then
let r = { sys[k](sys, e[sys.name], e, unpack(args)) }
if r[1] == false then
break
elseif r[1] == true then
args = { select(2, unpack(r)) }
end
end
end
return unpack(args)
end
return _entity_m_mt[k]
end
})
_previous = {}
}, { __index = system_mt })
world._entity_m_mt.__index = world._entity_m_mt
world.world = world
world.systems = recInstanciateSystems(world, {...})
recCallOnAddToWorld(world, world.systems)