Added a timer module

Author: Björn Ritzl

examples/timer/timer.collection

@@ -0,0 +1,37 @@
+name: "timer"
+scale_along_z: 0
+embedded_instances {
+  id: "go"
+  data: "components {\n"
+  "  id: \"script\"\n"
+  "  component: \"/examples/timer/timer.script\"\n"
+  "  position {\n"
+  "    x: 0.0\n"
+  "    y: 0.0\n"
+  "    z: 0.0\n"
+  "  }\n"
+  "  rotation {\n"
+  "    x: 0.0\n"
+  "    y: 0.0\n"
+  "    z: 0.0\n"
+  "    w: 1.0\n"
+  "  }\n"
+  "}\n"
+  ""
+  position {
+    x: 0.0
+    y: 0.0
+    z: 0.0
+  }
+  rotation {
+    x: 0.0
+    y: 0.0
+    z: 0.0
+    w: 1.0
+  }
+  scale3 {
+    x: 1.0
+    y: 1.0
+    z: 1.0
+  }
+}

examples/timer/timer.script

@@ -0,0 +1,19 @@
+local timer = require "ludobits.m.timer"
+
+function init(self)
+	self.t1 = timer.once(3, function()
+		print("t1 has fired")
+	end)
+	self.t2 = timer.every(1, function()
+		print("t2 has fired")
+	end)
+	self.t3 = timer(5, function()
+		print("t3 has fired")
+	end)
+end
+
+function update(self, dt)
+	self.t1.update(dt)
+	self.t2.update(dt)
+	self.t3.update(dt)
+end

ludobits/m/timer.lua

@@ -0,0 +1,74 @@
+--- Simple timer module to delay a function call or
+-- repeatedly call a function
+--
+-- @usage
+-- function init(self)
+-- 	self.t1 = timer.once(3, function()
+-- 		print("t1 has fired")
+-- 	end)
+-- 	self.t2 = timer.every(1, function()
+-- 		print("t2 has fired")
+-- 	end)
+-- 	self.t3 = timer(5, function()
+-- 		print("t3 has fired")
+-- 	end)
+-- end
+-- 
+-- function update(self, dt)
+-- 	self.t1.update(dt)
+-- 	self.t2.update(dt)
+-- 	self.t3.update(dt)
+-- end
+
+local M = {}
+
+
+--- Create a timer that will call a function after a certain time
+-- has elapsed.
+-- @param seconds The number of seconds before the callback should be invoked
+-- @param callback The function to invoke when the time has elapsed
+-- @return The timer instance
+function M.once(seconds, callback)
+	assert(seconds and type(seconds) == "number" and seconds >= 0, "You must provide a positive number")
+	assert(callback, "You must provide a callback")
+	
+	local timer = {
+		seconds = seconds,
+	}
+	
+	function timer.update(dt)
+		assert(dt and type(dt) == "number", "You must provide a dt")
+		if timer.seconds <= 0 then
+			return
+		end
+		timer.seconds = timer.seconds - dt
+		if timer.seconds <= 0 then
+			callback(timer)
+		end
+	end
+	
+	function timer.reset()
+		timer.seconds = seconds
+	end
+	
+	return timer
+end
+
+--- Create a timer that will call a function with a regular interval
+-- @param seconds The number of seconds between callbacks
+-- @param callback The function to invoke
+-- @return The timer instance
+function M.every(seconds, callback)
+	local timer = M.once(seconds, function(timer)
+		callback(timer)
+		timer.seconds = seconds
+	end)
+	return timer
+end
+
+
+return setmetatable(M, {
+	__call = function(self, ...)
+		return M.once(...)
+	end
+})

test/test.script

@@ -1,12 +1,14 @@
 local test_input = require "test.test_input"
 local test_broadcast = require "test.test_broadcast"
 local test_flow = require "test.test_flow"
+local test_timer = require "test.test_timer"
 
 local deftest = require "deftest.deftest"
 
 function init(self)
 	deftest.add(test_input)
 	deftest.add(test_broadcast)
 	deftest.add(test_flow)
+	deftest.add(test_timer)
 	deftest.run()
 end

test/test_timer.lua

@@ -0,0 +1,58 @@
+local mock = require "deftest.mock"
+
+return function()
+	local timer = require "ludobits.m.timer"
+
+	local o = {
+		cb = function() end
+	}
+	
+	describe("timer", function()
+		before(function()
+			mock.mock(o)
+		end)
+
+		after(function()
+			mock.unmock(o)
+		end)
+
+		it("should call a function after a certain time has elapsed", function()
+			local t = timer.once(3, o.cb)
+			t.update(2)
+			assert(o.cb.calls == 0)
+			t.update(1)
+			assert(o.cb.calls == 1)
+			t.update(3)
+			assert(o.cb.calls == 1)
+		end)
+		
+		it("should be possible to reset a timer", function()
+			local t = timer.once(3, o.cb)
+			t.update(3)
+			assert(o.cb.calls == 1)
+			t.reset()
+			t.update(3)
+			assert(o.cb.calls == 2)
+		end)
+		
+		it("should be possible to directly manipulate timer delay", function()
+			local t = timer.once(3, o.cb)
+			assert(t.seconds)
+			t.seconds = 5
+			t.update(3)
+			assert(o.cb.calls == 0)
+			t.update(2)
+			assert(o.cb.calls == 1)
+		end)
+
+		it("should be possible to repeat a callback with a regular interval", function()
+			local t = timer.every(3, o.cb)
+			t.update(3)
+			assert(o.cb.calls == 1)
+			t.update(3)
+			assert(o.cb.calls == 2)
+			t.update(3)
+			assert(o.cb.calls == 3)
+		end)
+	end)
+end