Initial commit

fluid/instance.lua

@@ -0,0 +1,86 @@
+local PATH = (...):gsub('%.[^%.]+$', '')
+
+local Pool         = require(PATH..".pool")
+local EventManager = require(PATH..".eventManager")
+
+local Instance = {}
+Instance.__index = Instance
+
+function Instance.new()
+   local instance = setmetatable({
+      entities     = Pool(),
+      eventManager = EventManager(),
+
+      systems      = {},
+      namedSystems = {},
+   }, Instance)
+
+   return instance
+end
+
+function Instance:addEntity(e)
+   e.instance = self
+   self.entities:add(e)
+   self:checkEntity(e)
+end
+
+function Instance:checkEntity(e)
+   for _, system in ipairs(self.systems) do
+      if system:entityUpdated(e) then
+         e.systems[#e.systems + 1] = system
+      end
+   end
+end
+
+function Instance:destroyEntity(e)
+   self.entities:remove(e)
+
+   for _, system in ipairs(e.systems) do
+      system:remove(e)
+   end
+end
+
+function Instance:addSystem(system, eventName)
+   if not self.namedSystems[system] then
+      self.systems[#self.systems + 1] = system
+      self.namedSystems[system]       = system
+   end
+
+   self.eventManager:register(eventName, system)
+
+   return self
+end
+
+function Instance:removeSystem(system)
+   for index, other in ipairs(self.systems) do
+      if system == other then
+         table.remove(self.systems, index)
+      end
+   end
+
+   self.namedSystems[system] = nil
+
+   return self
+end
+
+function Instance:emit(...)
+   self.eventManager:emit(...)
+
+   return self
+end
+
+function Instance:update(dt)
+   self:emit("update", dt)
+
+   return self
+end
+
+function Instance:draw()
+   self:emit("draw")
+
+   return self
+end
+
+return setmetatable(Instance, {
+   __call = function(_, ...) return Instance.new(...) end,
+})