Merge pull request #302 from erf/simplify-gameloop

Simplify GameLoop using a Ticker

CHANGELOG.md

@@ -6,7 +6,7 @@
 
 ## 0.20.0
 - Refactor game.dart classes into separate files
-- Split up gameloop into separate GameLoop class
+- Adding a GameLoop class which uses a Ticker for updating game
 - Adding sprites example
 - Made BaseGame non-abstract and removed SimpleGame
 - Adding SpriteButton Widget

lib/game/game_loop.dart

@@ -2,29 +2,14 @@ import 'package:flutter/scheduler.dart';
 
 class GameLoop {
  Function callback;
- int _frameCallbackId;
- bool _running = false;
  Duration previous = Duration.zero;
+ Ticker _ticker;
 
- GameLoop(this.callback);
-
- void scheduleTick() {
- _running = true;
- _frameCallbackId = SchedulerBinding.instance.scheduleFrameCallback(_tick);
- }
-
- void unscheduleTick() {
- _running = false;
- if (_frameCallbackId != null) {
- SchedulerBinding.instance.cancelFrameCallbackWithId(_frameCallbackId);
- }
+ GameLoop(this.callback) {
+ _ticker = Ticker(_tick);
  }
 
  void _tick(Duration timestamp) {
- if (!_running) {
- return;
- }
- scheduleTick();
  final double dt = _computeDeltaT(timestamp);
  callback(dt);
  }
@@ -38,16 +23,20 @@ class GameLoop {
  return delta.inMicroseconds / Duration.microsecondsPerSecond;
  }
 
+ void start() {
+ _ticker.start();
+ }
+
+ void stop() {
+ _ticker.stop();
+ }
+
  void pause() {
- if (_running) {
- previous = Duration.zero;
- unscheduleTick();
- }
+ _ticker.muted = true;
+ previous = Duration.zero;
  }
 
  void resume() {
- if (!_running) {
- scheduleTick();
- }
+ _ticker.muted = false;
  }
 }

lib/game/game_render_box.dart

@@ -35,7 +35,7 @@ class GameRenderBox extends RenderBox with WidgetsBindingObserver {
  game.resumeEngineFn = gameLoop.resume;
 
  if (game.runOnCreation) {
- gameLoop.scheduleTick();
+ gameLoop.start();
  }
 
  _bindLifecycleListener();
@@ -45,7 +45,7 @@ class GameRenderBox extends RenderBox with WidgetsBindingObserver {
  void detach() {
  super.detach();
  game.onDetach();
- gameLoop.unscheduleTick();
+ gameLoop.stop();
  _unbindLifecycleListener();
  }