added red alien ships as pod in not running status

main/timer.lua

@@ -0,0 +1,89 @@
+--- Module that can be used to get a callback when a certain amount of time has elapsed
+--
+-- @usage
+-- local timer = require "timer"
+-- function init(self)
+-- 		self.t1 = timer.seconds(2, function()
+--			print("2 seconds have elapsed")
+--		end)
+-- 		self.t2 = timer.seconds(5, function()
+--			print("5 seconds have elapsed")
+--		end)
+-- end
+--
+-- function update(self, dt)
+--		timer.update(dt)
+--		print("Time left on timer 1:", timer.time_left(self.t1))
+--		print("Time left on timer 2:", timer.time_left(self.t2))
+-- end
+
+local M = {}
+
+local timers = {}
+
+local instance_count = 0
+
+--- Get a callback when a certain number of seconds has elapsed
+-- @param seconds The number of seconds to wait before invoking the callback
+-- @param callback The function to call when the specified number of seconds has elapsed
+-- @return Id of the created timer. Can be used to query the time left
+function M.seconds(seconds, callback)
+	instance_count = instance_count + 1
+	timers[instance_count] = { seconds = seconds, callback = callback }
+	return instance_count
+end
+
+--- Get a callback when a certain number of frames have elapsed
+-- @param frames The number of frames to wait before invoking the callback
+-- @param callback The function to call when the specified number of frames has elapsed
+-- @return Id of the created timer. Can be used to query the time left
+function M.frames(frames, callback)
+	instance_count = instance_count + 1
+	if frames == 0 then
+		callback()
+	else
+		timers[instance_count] = { frames = frames, callback = callback }
+	end
+	return instance_count
+end
+
+--- Get time left for a timer
+-- @param id Id of the timer
+-- @return The time left (seconds or frames)
+function M.time_left(id)
+	return timers[id] and (timers[id].seconds or timers[id].frames) or nil
+end
+
+--- Cancel all timers. Callbacks will NOT be invoked.
+function M.cancel_all()
+	timers = {}
+end
+
+--- Cancel a single timer. The callback will NOT be invoked
+-- @param id Id of the timer to cancel
+function M.cancel(id)
+	timers[id] = nil
+end
+
+--- Call this function once per frame to continuously check for completed timers
+-- @param dt Time in seconds that has elapsed since the last call
+function M.update(dt)
+	for id,timer in pairs(timers) do
+		if timer.frames then
+			timer.frames = timer.frames - 1
+			if timer.frames == 0 then
+				timers[id] = nil
+				timer.callback()
+			end
+		elseif timer.seconds then
+			timer.seconds = timer.seconds - dt
+			if timer.seconds <= 0 then
+				timers[id] = nil
+				timer.callback()
+			end
+		end
+	end
+end
+
+
+return M