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Étienne Reuh Fildadut
9d2e886609
The component methods system was awkward and didn't give much benefit compared to just using methods on Systems. Plus now we really only have data in entities. Since we don't have component methods, the callback system had to be replaced; I integrated it with the default System methods since it's a relatively common behavior.
850 lines
27 KiB
Text
850 lines
27 KiB
Text
--[[-- ECS ([entity compenent system](https://en.wikipedia.org/wiki/Entity_component_system)) library for Lua.
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Entity Component System library, inspired by the excellent [tiny-ecs](https://github.com/bakpakin/tiny-ecs/tree/master) by bakpakin.
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Main differences include:
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* ability to nest systems (more organisation potential);
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* instanciation of systems for each world (no shared state) (several worlds can coexist at the same time easily);
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* adding and removing entities is done instantaneously (no going isane over tiny-ecs cache issues);
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* ability to add and remove components from entities after they were added to the world (more dynamic entities).
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And a fair amount of other quality-of-life features.
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The goals of this library are similar in spirit to tiny-ecs: simple to use, flexible, and useful.
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The more advanced features it provides relative to tiny-ecs are made so that you can completely ignore them
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if you don't use them.
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The module returns a table that contains several functions, `world` or `scene` are starting points
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to create your world.
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No mandatory dependency.
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Optional dependency: `ubiquitousse.scene`, to allow quick creation of ECS-based scenes (`ecs.scene`).
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@module ecs
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@usage
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-- Same example as tiny-ecs', for comparaison purposes
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local ecs = require("ubiquitousse.ecs")
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local talkingSystem = {
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filter = { "name", "mass", "phrase" },
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process = function(self, c, e, dt)
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e.mass = e.mass + dt * 3
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print(("%s who weighs %d pounds, says %q."):format(e.name, e.mass, e.phrase))
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end
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}
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local joe = {
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name = "Joe",
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phrase = "I'm a plumber.",
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mass = 150,
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hairColor = "brown"
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}
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local world = ecs.world(talkingSystem)
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world:add(joe)
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for i = 1, 20 do
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world:update(1)
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end
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--]]
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local loaded, scene
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if ... then loaded, scene = pcall(require, (...):match("^(.-)ecs").."scene") end
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if not loaded then scene = nil end
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let ecs
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-- TODO: Implement a skip list for faster search.
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-- better control over system order: process, draw, methods? (for lag reasons and dependencies)
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--- Entities are regular tables that get processed by `System`s.
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--
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-- The idea is that entities _should_ only contain data and no code; it's the systems that are responsible for the actual processing
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-- (but it's your game, do as you want).
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--
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-- This data is referred to, and organized in, "components".
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-- @type Entity
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--[[-- Components.
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Entities are Lua tables, and thus contain key-values pairs: each one of these pairs is called a "component". The data can be
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whatever you want, and ideally each component _should_ store the data for one singular aspect of the entity, for example its position, name, etc.
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This library does not do any kind of special processing by itself on the entity tables and take them as is (no metatable, no methamethods, etc.),
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so you are free to handle them as you want in your systems or elsewhere.
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Since it's relatively common for systems to only operate on a single component, as a shortcut the library often consider what it calls the "system component":
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that is, the component in the entity that has the same name as the system (if it exists).
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@doc Component
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@usage
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-- example entity
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local entity = {
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position = { x = 0, y = 52 }, -- a "position" component
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sprite = newSprite("awesomeguy.png") -- a "sprite" component
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}
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-- example "sprite" system
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local sprite = {
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name = "sprite",
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filter = "sprite", -- process entities that have a "sprite" component
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-- systems callbacks that are called per-entity often give you the system component as an argument
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-- the system component is the component with the same name as the system, thus here the sprite component
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render = function(self, component, entity)
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-- component == entity.sprite
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component:draw()
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end
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}
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]]--
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--- Recursively remove subsystems from a system.
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let recDestroySystems = (system)
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for i=#system.systems, 1, -1 do
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let s = system.systems[i]
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recDestroySystems(s)
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s:onDestroy()
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system.systems[i] = nil
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if s.name then
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system.world.s[s.name] = nil
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end
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end
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end
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--- Recursively call :clear and :onRemoveFromWorld to a list of systems in a world.
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let recCallOnRemoveFromWorld = (world, systems)
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for _, s in ipairs(systems) do
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s:clear()
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recCallOnRemoveFromWorld(world, s.systems)
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s:onRemoveFromWorld(world)
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end
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end
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--- Iterate through the next entity, based on state s: { previousLinkedListItem }
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let nextEntity = (s)
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if s[1] then
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let var = s[1][1]
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s[1] = s[1][2]
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return var
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else
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return nil
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end
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end
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--- Recursively copy content of a into b if it isn't already present.
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-- Don't copy keys, will preserve metatable but not copy them.
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let copy = (a, b, cache={})
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for k, v in pairs(a) do
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if type(v) == "table" then
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if b[k] == nil then
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if cache[v] then
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b[k] = cache[v]
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else
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cache[v] = {}
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b[k] = cache[v]
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copy(v, b[k], cache)
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setmetatable(b[k], getmetatable(v))
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end
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elseif type(b[k]) == "table" then
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copy(v, b[k], cache)
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end
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elseif b[k] == nil then
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b[k] = v
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end
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end
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end
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--[[-- Systems and Worlds.
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Systems are what do the processing on your entities. A system contains a list of entities; the entities in this list are selected
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using a `filter`, and the system will only operate on those filtered entities.
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A system can also be created that do not accept any entity (`filter = false`, this is the default): such a system can still be
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used to do processing that don't need to be done per-entity but still behave like other systems (e.g. to do some static calculation each update).
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The system also contains `callbacks`, these define the actual processing done on the system and its entities and you will want to redefine
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at least one of them to make your system actually do something.
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Then you can call `System:update`, `System:draw`, `System:emit` or `System:callback` at appropriate times and the system will call the
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associated callbacks on itself and its entities, and then pass it to its subsystems. In practise you would likely only call these on
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the world system, so the callbacks are correctly propagated to every single system in the world.
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Systems are defined as regular tables with all the fields and methods you need in it. However, when a system is added to
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a world, the table you defined is not used directly, but we use what we call an "instancied system": think of it of an instance of your system
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like if it were a class.
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The instancied system will have a metatable set that gives it some methods and fields defined by the library on top of what you defined.
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Modifying the instancied system will only modify this instance and not the original system you defined, so several instances of your system
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can exist in different worlds (note that the original system is not copied on instancing; if you reference a table in the original system it will use the
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original table directly).
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Systems can have subsystems; that is a system that behave as an extension of their parent system. They only operates on the entities already
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present in their parent subsystem, only update when their parent system updates, etc. You can thus organize your systems in a hierarchy to
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avoid repeating your filters or allow controlling several system from a single parent system.
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The top-level system is called the "world"; it behaves in exactly the same way as other systems, and accept every entity by default.
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@type System
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@usage
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local sprite = {
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filter = { "sprite", "position" }, -- only operate on entities with "sprite" and "position" components
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systems = { animated }, -- subsystems: they only operate on entities already filtered by this system (on top of their own filtering)
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-- Called when an entity is added to this system.
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onAdd = function(self, component, entity)
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print("Added an entity, entity count in the system:", self.entityCount) -- self refer to the instancied system
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end,
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-- Called when the system is updated, for every entity the system
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process = function(self, component, entity, dt)
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-- processing...
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end
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}
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local world = ecs.world(system) -- instanciate a world with the sprite system (and all its subsystems)
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-- Add an entity: doesn't pass the filtering, so nothing happens
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world:add {
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name = "John"
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}
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-- Added to the sprite system! Call sprite:onAdd, and also try to add it to its subsystems
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world:add {
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sprite = newSprite("example.png"),
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position = { x=5, y=0 }
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}
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-- Trigger sprite:onUpdate and sprite:process callbacks
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world:update(dt)
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--]]
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let system_mt = {
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--- Modifiable fields.
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--
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-- Every field defined below is optional and can be accessed or redefined at any time, unless written otherwise. Though you would typically set them
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-- before instanciating your systems.
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-- @doc modifiable
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--- Name of the system.
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-- Used to create a field with the system's name in `world.s` and determine the associated system component.
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-- If not set, the system will not appear in `world.s` and gives `nil` instead of the system component in callbacks.
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--
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-- Do not change after system instanciation.
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-- @ftype string
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-- @ftype nil if no name
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name = nil,
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--- List of subsystems.
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-- On a instancied system, this is a list of the same subsystems, but instancied for this world.
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--
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-- Do not change after system instanciation.
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-- @ftype table
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-- @ftype nil if no subsystem
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systems = nil,
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--- If not `false`, the system will only update every interval seconds.
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-- `false` by default.
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-- @ftype number interval of time between each update
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-- @ftype false to disable
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interval = false,
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--- The system and its susbsystems will only update if this is `true`.
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-- `true` by default.
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-- @ftype boolean
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active = true,
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--- The system and its subsystems will only draw if this is `true`.
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-- `true` by default.
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-- @ftype boolean
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visible = true,
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--- Defaults value to put into the entities's system component when they are added.
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--
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-- If this is table, will recursively fill missing values.
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-- Metatables will be preserved during the copy but not copied themselves.
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--
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-- Changing this will not affect entities already in the system.
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-- Doesn't have any effect if the system doesn't have a name.
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-- @ftype any
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-- @ftype nil if no default
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default = nil,
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--- Callbacks.
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--
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-- Functions that are called when something happens in the system.
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-- Redefine them to change system behaviour.
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-- @doc callbacks
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--- Called when checking if an entity should be added to this system.
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-- Returns `true` if the entity should be added to this system (and therefore its subsystems).
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--
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-- If this is a string or a table, it will be converted to a filter function on instanciation using ecs.any.
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--
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-- If this `true`, will accept every entity; if `false`, reject every entity.
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--
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-- Will only test entities when they are added; changing this after system creation will not affect entities already in the system.
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--
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-- By default, rejects everything.
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-- @callback
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-- @tparam table e entity table to check
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-- @treturn boolean `true` if entity should be added
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filter = :(e) return false end,
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--- Called when adding an entity to this system determining its order.
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-- Returns `true` if `e1 <=` e2 (i.e., if `e1` should be processed before `e2` in this system). e1 and e2 are two entities.
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--
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-- Used to place the entity in the sorted entity list when it is added; changing this after system creation
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-- will not change the order of entities already in the system.
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--
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-- By default, new entities are added at the start of the list.
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-- @callback
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-- @tparam Entity e1 entity table to check for inferiority
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-- @tparam Entity e2 entity table to check for superiority
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-- @treturn boolean `true` if e1 <= e2
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compare = :(e1, e2) return true end,
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--- Called when adding an entity to the system.
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-- @callback
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-- @tparam Component c the entity's system component
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-- @tparam Entity e the entity table
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onAdd = :(c, e) end,
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--- Called when removing an entity from the system.
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-- @callback
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-- @tparam Component c the entity's system component
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-- @tparam Entity e the entity table
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onRemove = :(c, e) end,
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--- Called when the system is instancied, before any call to `System:onAddToWorld` (including other systems in the world).
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-- @callback
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onInstance = :() end,
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--- Called when the system is added to a world.
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-- @callback
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-- @tparam System world world system
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onAddToWorld = :(world) end,
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--- Called when the system is removed from a world (i.e., the world is destroyed).
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-- @callback
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-- @tparam System world world system
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onRemoveFromWorld = :(world) end,
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--- Called when the world is destroyed, after every call to `System:onRemoveFromWorld` (including other systems in the world).
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-- @callback
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onDestroy = :() end,
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--- Called when updating the system.
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-- @callback
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-- @number dt delta-time since last update
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onUpdate = :(dt) end,
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--- Called when drawing the system.
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-- @callback
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onDraw = :() end,
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--- Called when updating the system, for every entity the system contains. Called after `System:onUpdate` was called on the system.
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-- @callback
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-- @tparam Component c the entity's system component
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-- @tparam Entity e the entity table
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-- @number dt delta-time since last update
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process = :(c, e, dt) end,
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--- Called when drawing the system, for every entity the system contains. Called after `System:onDraw` was called on the system.
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-- @callback
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-- @tparam Component c the entity's system component
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-- @tparam Entity e the entity table
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render = :(c, e) end,
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--- Read-only fields.
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--
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-- Fields available on instancied systems. Don't modify them unless you like broken things.
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-- @doc ro
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--- The world the system belongs to.
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-- @ftype System world
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-- @ro
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world = nil,
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--- Shortcut to `System.world`.
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-- @ftype System world
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-- @ro
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w = nil,
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--- Number of entities in the system.
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-- @ftype integer
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-- @ro
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entityCount = 0,
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--- Map of all named systems in the world (not only subsystems). Same for every system from the same world.
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-- @ftype table {[system.name]=instanciedSystem, ...}
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-- @ro
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s = nil,
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--- Private fields ---
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--- First element of the linked list of entities: { entity, next_element }.
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-- @local
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_first = nil,
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--- Associative map of entities in the system and their previous linked list element (or `true` if first element).
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-- This make the list effectively a doubly linked list, but with easy access to the previous element using this map (and therefore O(1) deletion).
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-- @local
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_previous = nil,
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--- Amount of time waited since last update (if interval is set).
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-- @local
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_waited = 0,
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--- Methods.
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--
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-- Methods available on instancied systems.
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-- @doc smethods
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--- Add entities to the system and its subsystems.
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--
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-- Will skip entities that are already in the system.
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--
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-- Entities are added to subsystems after they were succesfully added to their parent system.
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--
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-- If this is called on a subsystem instead of the world, be warned that this will bypass all the parent's systems filters.
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-- If you do that, since `System:remove` will not search for entities in systems where they should have been filtered out, the added entities will not be removed
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-- when calling `System:remove` on a parent system or the world. The entity can be removed by calling `System:remove` on the system `System:add` was called on.
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--
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-- Complexity: O(1) per unordered system, O(entityCount) per ordered system.
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-- @tparam Entity e entity to add
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-- @tparam Entity... ... other entities to add
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-- @treturn Entity,... `e,...` the function arguments
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add = :(e, ...)
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if e ~= nil and not @_previous[e] and @filter(e) then
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-- copy default system component
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if @name and @default then
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copy({ [@name] = @default }, e)
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end
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-- add to linked list
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if @_first == nil then
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@_first = { e, nil }
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@_previous[e] = true
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elseif @compare(e, @_first[1]) then
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let nxt = @_first
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@_first = { e, nxt }
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@_previous[e] = true
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@_previous[nxt[1]] = @_first
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else
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let entity = @_first
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while entity[2] ~= nil do
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if @compare(e, entity[2][1]) then
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let nxt = entity[2]
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entity[2] = { e, nxt }
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@_previous[e] = entity
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@_previous[nxt[1]] = entity[2]
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break
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end
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entity = entity[2]
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end
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if entity[2] == nil then
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entity[2] = { e, nil }
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@_previous[e] = entity
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end
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end
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-- notify addition
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@entityCount += 1
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@onAdd(e[@name], e)
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-- add to subsystems (if it wasn't immediately removed in onAdd)
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if @_previous[e] then
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for _, s in ipairs(@systems) do
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s:add(e)
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end
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end
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end
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if ... then
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return e, @add(...)
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else
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return e
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end
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end,
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--- Remove entities from the system and its subsystems.
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--
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-- Will skip entities that are not in the system.
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--
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-- Entities are removed from subsystems before they are removed from their parent system.
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--
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-- If you intend to call this on a subsystem instead of the world, please read the warning in `System:add`.
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--
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-- Complexity: O(1) per system.
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-- @tparam Entity e entity to remove
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-- @tparam Entity... ... other entities to remove
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-- @treturn Entity,... `e,...` the function arguments
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remove = :(e, ...)
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if e ~= nil then
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if @_previous[e] then
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-- remove from subsystems
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for _, s in ipairs(@systems) do
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s:remove(e)
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end
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end
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if @_previous[e] then -- recheck in case it was removed already from a subsystem onRemove callback
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-- remove from linked list
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let prev = @_previous[e]
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if prev == true then
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@_first = @_first[2]
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if @_first then
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@_previous[@_first[1]] = true
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end
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else
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prev[2] = prev[2][2]
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if prev[2] then
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@_previous[prev[2][1]] = prev
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end
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end
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-- notify removal
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@_previous[e] = nil
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@entityCount -= 1
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@onRemove(e[@name], e)
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end
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end
|
|
if ... then
|
|
return e, @remove(...)
|
|
else
|
|
return e
|
|
end
|
|
end,
|
|
--- Refresh an entity's systems.
|
|
--
|
|
-- Behave similarly to `System: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.
|
|
-- @tparam Entity e entity to refresh
|
|
-- @tparam Entity... ... other entities to refresh
|
|
-- @treturn Entity,... `e,...` the function arguments
|
|
refresh = :(e, ...)
|
|
if e ~= nil then
|
|
if not @_previous[e] then
|
|
@add(e)
|
|
elseif @_previous[e] then
|
|
if not @filter(e) then
|
|
@remove(e)
|
|
else
|
|
for _, s in ipairs(@systems) do
|
|
s:refresh(e)
|
|
end
|
|
end
|
|
end
|
|
end
|
|
if ... then
|
|
return e, @refresh(...)
|
|
else
|
|
return e
|
|
end
|
|
end,
|
|
--- Reorder an entity.
|
|
--
|
|
-- Will recalculate the entity position in the entity list for this system and its subsystems.
|
|
-- Will skip entities that are not in the system.
|
|
--
|
|
-- Complexity: O(entityCount) per system.
|
|
-- @tparam Entity e entity to reorder
|
|
-- @tparam Entity... ... other entities to reorder
|
|
-- @treturn Entity,... `e,...` the function arguments
|
|
reorder = :(e, ...)
|
|
if e ~= nil then
|
|
if @_previous[e] then
|
|
let prev = @_previous[e] -- { prev, { e, next } }
|
|
let next = prev == true and @_first[2] or prev[2][2]
|
|
-- remove e from linked list
|
|
if prev == true then
|
|
@_first = @_first[2]
|
|
else
|
|
prev[2] = next
|
|
end
|
|
if next then
|
|
@_previous[next[1]] = prev
|
|
end
|
|
-- find position so that prev < e <= next
|
|
while prev ~= true and @compare(e, prev[1]) do -- ensure prev < e
|
|
next = prev
|
|
prev = @_previous[prev[1]]
|
|
end
|
|
while next ~= nil and not @compare(e, next[1]) do -- ensure e <= next
|
|
prev = next
|
|
next = next[2]
|
|
end
|
|
-- reinsert e in linked list
|
|
let new = { e, next }
|
|
@_previous[e] = prev
|
|
if next then
|
|
@_previous[next[1]] = new
|
|
end
|
|
if prev == true then
|
|
@_first = new
|
|
else
|
|
prev[2] = new
|
|
end
|
|
-- Reorder in subsystems
|
|
for _, s in ipairs(@systems) do
|
|
s:reorder(e)
|
|
end
|
|
end
|
|
end
|
|
if ... then
|
|
return e, @reorder(...)
|
|
else
|
|
return e
|
|
end
|
|
end,
|
|
--- Returns `true` if all these entities are in the system.
|
|
--
|
|
-- Complexity: O(1).
|
|
-- @tparam Entity e entity that may be in the system
|
|
-- @tparam Entity... ... other entities that may be in the system
|
|
-- @treturn boolean `true` if every entity is in the system
|
|
has = :(e, ...)
|
|
let has = e == nil or not not @_previous[e]
|
|
if ... then
|
|
return has and @has(...)
|
|
else
|
|
return has
|
|
end
|
|
end,
|
|
--- Returns an iterator that iterate through the entties in this system, in order.
|
|
-- @treturn iterator iterator over the entities in this system
|
|
iter = :()
|
|
return nextEntity, { @_first }
|
|
end,
|
|
--- Remove every entity from the system and its subsystems.
|
|
clear = :()
|
|
for e in @iter() do
|
|
@remove(e)
|
|
end
|
|
for _, s in ipairs(@systems) do
|
|
s:clear()
|
|
end
|
|
end,
|
|
--- Try to update the system and its subsystems. Should be called on every game update.
|
|
--
|
|
-- Subsystems are updated after their parent system.
|
|
-- @number dt delta-time since last update
|
|
update = :(dt)
|
|
if @active then
|
|
if @interval then
|
|
@_waited += dt
|
|
if @_waited < @interval then
|
|
return
|
|
end
|
|
end
|
|
@onUpdate(dt)
|
|
if @process ~= system_mt.process then
|
|
for e in @iter() do
|
|
@process(e[@name], e, dt)
|
|
end
|
|
end
|
|
for _, s in ipairs(@systems) do
|
|
s:update(dt)
|
|
end
|
|
if @interval then
|
|
@_waited -= @interval
|
|
end
|
|
end
|
|
end,
|
|
--- Try to draw the system and its subsystems. Should be called on every game draw.
|
|
--
|
|
-- Subsystems are drawn after their parent system.
|
|
draw = :()
|
|
if @visible then
|
|
@onDraw()
|
|
if @render ~= system_mt.render then
|
|
for e in @iter() do
|
|
@render(e[@name], e)
|
|
end
|
|
end
|
|
for _, s in ipairs(@systems) do
|
|
s:draw()
|
|
end
|
|
end
|
|
end,
|
|
--- Trigger a custom callback on a single entity.
|
|
--
|
|
-- This will call the `System:name(c, e, ...)` method in this system and its subsystems,
|
|
-- if the method exists and the entity is in the system. `c` is the system [component](#Entity.Component)
|
|
-- associated with the current system, and `e` is the `Entity`.
|
|
--
|
|
-- Think of it as a way to perform custom callbacks issued from an entity event, similar to `System:onAdd`.
|
|
-- @tparam string name name of the callback
|
|
-- @tparam Entity e the entity to perform the callback on
|
|
-- @param ... other arguments to pass to the callback
|
|
callback = :(name, e, ...)
|
|
-- call callback
|
|
if @_previous[e] and @[name] then
|
|
@[name](@, e[@name], e, ...)
|
|
end
|
|
-- callback on subsystems (if it wasn't removed during the callback)
|
|
if @_previous[e] then
|
|
for _, ss in ipairs(@systems) do
|
|
ss:callback(name, e, ...)
|
|
end
|
|
end
|
|
end,
|
|
--- Emit an event on the system.
|
|
--
|
|
-- This will call the `System:name(...)` method in this system and its subsystems,
|
|
-- if the method exists.
|
|
--
|
|
-- Think of it as a way to perform custom callbacks issued from a general event, similar to `System:onUpdate`.
|
|
--
|
|
-- The called methods may return a string value to affect the event propagation behaviour:
|
|
--
|
|
-- * if a callback returns `"stop"`, the event will not be propagated to the subsystems.
|
|
-- * if a callback returns `"capture"`, the event will not be propagated to the subsystems _and_
|
|
-- its sibling systems (i.e. completely stop the propagation of the event).
|
|
--
|
|
-- `"stop"` would be for example used to disable some behaviour in the system and its subsystems (like `active = false` can
|
|
-- disable `System:onUpdate` behaviour on the system and its subsystems).
|
|
--
|
|
-- `"capture"` would be for example used to prevent other systems from handling the event (for example to make sure an
|
|
-- input event is handled only once by a single system).
|
|
--
|
|
-- @tparam string name name of the callback
|
|
-- @param ... other arguments to pass to the callback
|
|
emit = :(name, ...)
|
|
-- call event
|
|
let status
|
|
if @[name] then
|
|
status = @[name](@, ...)
|
|
end
|
|
-- call event on subsystems (if it wasn't stopped or captured)
|
|
if status ~= "stop" and status ~= "capture" then
|
|
for _, s in ipairs(@systems) do
|
|
status = s:emit(name, ...)
|
|
if status == "capture" then break end
|
|
end
|
|
end
|
|
return status
|
|
end,
|
|
--- Remove all the entities and subsystems in this system.
|
|
destroy = :()
|
|
recCallOnRemoveFromWorld(@world, { @ })
|
|
recDestroySystems({ systems = { @ } })
|
|
end,
|
|
}
|
|
|
|
--- Self descriptive
|
|
let alwaysTrue = () return true end
|
|
let alwaysFalse = () return false 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
|
|
let system
|
|
-- instanciate system
|
|
system = setmetatable({
|
|
systems = recInstanciateSystems(world, s.systems or {}),
|
|
world = world,
|
|
w = world,
|
|
s = world.s,
|
|
_previous = {},
|
|
}, {
|
|
__index = :(k)
|
|
if s[k] ~= nil then
|
|
return s[k]
|
|
else
|
|
return system_mt[k]
|
|
end
|
|
end
|
|
})
|
|
if type(s.filter) == "string" then
|
|
system.filter = (_, e) return e[s.filter] ~= nil end
|
|
elseif type(s.filter) == "table" then
|
|
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
|
|
system:onInstance()
|
|
end
|
|
return t
|
|
end
|
|
--- Recursively call :onAddToWorld to a list of systems in a world.
|
|
let recCallOnAddToWorld = (world, systems)
|
|
for _, s in ipairs(systems) do
|
|
recCallOnAddToWorld(world, s.systems)
|
|
s:onAddToWorld(world)
|
|
end
|
|
end
|
|
|
|
--- ECS module.
|
|
-- @section end
|
|
ecs = {
|
|
--- Create and returns a world system based on a list of systems.
|
|
-- The systems will be instancied for this world.
|
|
-- @tparam table,... ... list of (uninstancied) systems
|
|
-- @treturn System the world system
|
|
world = (...)
|
|
let world = setmetatable({
|
|
filter = ecs.all(),
|
|
s = {},
|
|
_previous = {}
|
|
}, { __index = system_mt })
|
|
world.world = world
|
|
world.w = world
|
|
world.systems = recInstanciateSystems(world, {...})
|
|
recCallOnAddToWorld(world, world.systems)
|
|
return world
|
|
end,
|
|
|
|
--- Returns a filter that returns `true` if, for every argument, a field with the same name exists in the entity.
|
|
-- @tparam string,... ... list of field names that must be in entity
|
|
-- @treturn function(e) that returns `true` if e has all the fields
|
|
all = (...)
|
|
if ... then
|
|
let l = {...}
|
|
return function(s, e)
|
|
for _, k in ipairs(l) do
|
|
if e[k] == nil then
|
|
return false
|
|
end
|
|
end
|
|
return true
|
|
end
|
|
else
|
|
return alwaysTrue
|
|
end
|
|
end,
|
|
|
|
--- Returns a filter that returns `true` if one of the arguments if the name of a field in the entity.
|
|
-- @tparam string,... ... list of field names that may be in entity
|
|
-- @treturn function(e) that returns `true` if e has at leats one of the fields
|
|
any = (...)
|
|
if ... then
|
|
let l = {...}
|
|
return function(s, e)
|
|
for _, k in ipairs(l) do
|
|
if e[k] ~= nil then
|
|
return true
|
|
end
|
|
end
|
|
return false
|
|
end
|
|
else
|
|
return alwaysFalse
|
|
end
|
|
end,
|
|
|
|
--- If `uqt.scene` is available, returns a new scene that will consist of a ECS world with the specified systems and entities.
|
|
-- @require ubiquitousse.scene
|
|
-- @string name the name of the new scene
|
|
-- @tparam[opt={}] table systems list of systems to add to the world
|
|
-- @tparam[opt={}] table entities list of entities to add to the world
|
|
-- @treturn scene the new scene
|
|
scene = (name, systems={}, entities={})
|
|
assert(scene, "ubiquitousse.scene unavailable")
|
|
let s = scene.new(name)
|
|
let w
|
|
|
|
function s:enter()
|
|
w = ecs.world(unpack(systems))
|
|
w:add(unpack(entities))
|
|
end
|
|
function s:exit()
|
|
w:destroy()
|
|
end
|
|
function s:update(dt)
|
|
w:update(dt)
|
|
end
|
|
function s:draw()
|
|
w:draw()
|
|
end
|
|
|
|
return s
|
|
end
|
|
}
|
|
|
|
return ecs
|