Add serialization and deserialization functions to component, entity, world

concord/component.lua

@@ -18,6 +18,7 @@ function Component.new(populate)
    local componentClass = setmetatable({
       __populate = populate,
 
+      __name             = nil,
       __isComponentClass = true,
    }, Component.__mt)
 
@@ -32,22 +33,44 @@ end
 function Component:__populate() -- luacheck: ignore
 end
 
---- Internal: Creates and populates a new Component.
--- @param ... Varargs passed to the populate function
--- @return A new populated Component
-function Component:__initialize(...)
+function Component:serialize() -- luacheck: ignore
+end
+
+function Component:deserialize(data) -- luacheck: ignore
+end
+
+--- Internal: Creates a new Component.
+-- @return A new Component
+function Component:__new()
    local component = setmetatable({
       __componentClass = self,
 
       __isComponent      = true,
       __isComponentClass = false,
-   }, self)
+   }, self.__mt)
+
+   return component
+end
+
+--- Internal: Creates and populates a new Component.
+-- @param ... Varargs passed to the populate function
+-- @return A new populated Component
+function Component:__initialize(...)
+   local component = self:__new()
 
    self.__populate(component, ...)
 
    return component
 end
 
+function Component:hasName()
+   return self.__name and true or false
+end
+
+function Component:getName()
+   return self.__name
+end
+
 return setmetatable(Component, {
    __call = function(_, ...)
       return Component.new(...)

concord/components.lua

@@ -20,12 +20,22 @@ function Components.register(name, componentClass)
     end
 
     if (rawget(Components, name)) then
-        error("bad argument #2 to 'Components.register' (ComponentClass with name '"..name.."' was already registerd)", 3)
+        error("bad argument #2 to 'Components.register' (ComponentClass with name '"..name.."' was already registerd)", 3) -- luacheck: ignore
     end
 
     Components[name] = componentClass
+    componentClass.__name = name
 end
 
+function Components.has(name)
+    return Components[name] and true or false
+end
+
+function Components.get(name)
+    return Components[name]
+end
+
+
 return setmetatable(Components, {
     __index = function(_, name)
         error("Attempt to index ComponentClass '"..tostring(name).."' that does not exist / was not registered", 2)

concord/entity.lua

@@ -5,6 +5,7 @@
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
+local Components = require(PATH..".components")
 local Type       = require(PATH..".type")
 
 local Entity = {}
@@ -173,6 +174,41 @@ function Entity:getWorld()
    return self.__world
 end
 
+function Entity:serialize()
+   local data = {}
+
+   for _, component in pairs(self.__components) do
+      if component.__name then
+         local componentData = component:serialize()
+         componentData.__name = component.__name
+
+         data[#data + 1] = componentData
+      end
+   end
+
+   return data
+end
+
+function Entity:deserialize(data)
+   for i = 1, #data do
+      local componentData = data[i]
+
+      if (not Components[componentData.__name]) then
+         error("bad argument #1 to 'Entity:deserialize' (ComponentClass "..type(componentData.__name).." wasn't yet loaded)") -- luacheck: ignore
+      end
+
+      local componentClass = Components[componentData.__name]
+
+      local component = componentClass:__new()
+      component:deserialize(componentData)
+
+      self[componentClass] = component
+      self.__components[componentClass] = component
+
+      self:__dirty()
+   end
+end
+
 return setmetatable(Entity, {
    __call = function(_, ...)
       return Entity.new(...)

concord/world.lua

@@ -6,6 +6,7 @@
 
 local PATH = (...):gsub('%.[^%.]+$', '')
 
+local Entity = require(PATH..".entity")
 local Type   = require(PATH..".type")
 local List   = require(PATH..".list")
 local Utils  = require(PATH..".utils")
@@ -21,10 +22,10 @@ World.__mt = {
 -- @return The new World
 function World.new()
    local world = setmetatable({
-      entities = List(),
-      systems  = List(),
+      __entities = List(),
+      __systems  = List(),
 
-      events = {},
+      __events = {},
 
       __added   = List(), __backAdded   = List(),
       __removed = List(), __backRemoved = List(),
@@ -104,10 +105,10 @@ function World:__flush()
    for i = 1, self.__backAdded.size do
       e = self.__backAdded[i]
 
-      self.entities:__add(e)
+      self.__entities:__add(e)
 
-      for j = 1, self.systems.size do
-         self.systems[j]:__evaluate(e)
+      for j = 1, self.__systems.size do
+         self.__systems[j]:__evaluate(e)
       end
 
       self:onEntityAdded(e)
@@ -119,10 +120,10 @@ function World:__flush()
       e = self.__backRemoved[i]
 
       e.__world = nil
-      self.entities:__remove(e)
+      self.__entities:__remove(e)
 
-      for j = 1, self.systems.size do
-         self.systems[j]:__remove(e)
+      for j = 1, self.__systems.size do
+         self.__systems[j]:__remove(e)
       end
 
       self:onEntityRemoved(e)
@@ -133,8 +134,8 @@ function World:__flush()
    for i = 1, self.__backDirty.size do
       e = self.__backDirty[i]
 
-      for j = 1, self.systems.size do
-         self.systems[j]:__evaluate(e)
+      for j = 1, self.__systems.size do
+         self.__systems[j]:__evaluate(e)
       end
    end
    self.__backDirty:__clear()
@@ -168,18 +169,18 @@ function World:addSystem(systemClass)
    local system = systemClass(self)
 
    self.__systemLookup[systemClass] = system
-   self.systems:__add(system)
+   self.__systems:__add(system)
 
    for callbackName, callback in pairs(systemClass) do
       -- Skip callback if its blacklisted
       if (not blacklistedSystemFunctions[callbackName]) then
          -- Make container for all listeners of the callback if it does not exist yet
-         if (not self.events[callbackName]) then
-            self.events[callbackName] = {}
+         if (not self.__events[callbackName]) then
+            self.__events[callbackName] = {}
          end
 
          -- Add callback to listeners
-         local listeners = self.events[callbackName]
+         local listeners = self.__events[callbackName]
          listeners[#listeners + 1] = {
             system   = system,
             callback = callback,
@@ -188,8 +189,8 @@ function World:addSystem(systemClass)
    end
 
    -- Evaluate all existing entities
-   for j = 1, self.entities.size do
-      system:__evaluate(self.entities[j])
+   for j = 1, self.__entities.size do
+      system:__evaluate(self.__entities[j])
    end
 
    return self
@@ -243,7 +244,7 @@ function World:emit(functionName, ...)
       error("bad argument #1 to 'World:emit' (String expected, got "..type(functionName)..")")
    end
 
-	local listeners = self.events[functionName]
+	local listeners = self.__events[functionName]
 
    if listeners then
       for i = 1, #listeners do
@@ -263,17 +264,58 @@ end
 --- Removes all entities from the World
 -- @return self
 function World:clear()
-   for i = 1, self.entities.size do
-      self:removeEntity(self.entities[i])
+   for i = 1, self.__entities.size do
+      self:removeEntity(self.__entities[i])
    end
 
-   for i = 1, self.systems.size do
-      self.systems[i]:__clear()
+   for i = 1, self.__systems.size do
+      self.__systems[i]:__clear()
    end
 
    return self
 end
 
+function World:getEntities()
+   return self.__entities
+end
+
+function World:getSystems()
+   return self.__systems
+end
+
+function World:serialize()
+   self:__flush()
+
+   local data = {}
+
+   for i = 1, self.__entities.size do
+      local entity = self.__entities[i]
+
+      local entityData = entity:serialize()
+
+      data[i] = entityData
+   end
+
+   return data
+end
+
+function World:deserialize(data, append)
+   if (not append) then
+      self:clear()
+   end
+
+   for i = 1, #data do
+      local entityData = data[i]
+
+      local entity = Entity()
+      entity:deserialize(entityData)
+
+      self:addEntity(entity)
+   end
+
+   self:__flush()
+end
+
 --- Callback for when an Entity is added to the World.
 -- @param e The Entity that was added
 function World:onEntityAdded(e) -- luacheck: ignore

examples/serialization/init.lua

@@ -0,0 +1,69 @@
+local Concord = require("concord")
+
+local function display(t)
+    print("Table: " ..tostring(t))
+    for key, value in pairs(t) do
+        if type(value) == "table" then
+            display(value)
+        else
+            print(key, value)
+        end
+    end
+end
+
+local test_component_1 = Concord.component(function(e, x, y)
+    e.x = x or 0
+    e.y = y or 0
+end)
+Concord.components.register("test_component_1", test_component_1)
+
+function test_component_1:serialize()
+    return {
+        x = self.x,
+        y = self.y,
+    }
+end
+
+function test_component_1:deserialize(data)
+    self.x = data.x or 0
+    self.y = data.y or 0
+end
+
+local test_component_2 = Concord.component(function(e, foo)
+    e.foo = foo
+end)
+Concord.components.register("test_component_2", test_component_2)
+
+function test_component_2:serialize()
+    return {
+        foo = self.foo
+    }
+end
+
+function test_component_2:deserialize(data)
+    self.foo = data.foo
+end
+
+-- Test worlds
+local world_1 = Concord.world()
+local world_2 = Concord.world()
+
+-- Test Entity
+Concord.entity(world_1)
+:give(test_component_1, 100, 50)
+:give(test_component_2, "Hello World!")
+
+-- Serialize world
+local data = world_1:serialize()
+
+-- Deserialize world
+world_2:deserialize(data)
+
+-- Check result
+local test_entity_copy = world_2:getEntities()[1]
+
+local test_comp_1 = test_entity_copy[test_component_1]
+local test_comp_2 = test_entity_copy[test_component_2]
+
+print(test_comp_1.x, test_comp_1.y)
+print(test_comp_2.foo)

main.lua

@@ -0,0 +1 @@
+require("examples.serialization")