Allow Setting Color Change Speed for Variable Timestep

lib/game/Game.dart

@@ -21,8 +21,7 @@ class Game {
   }
 
   // In-World Logic Updates
-  void update([num speed]) {
-    print(speed);
+  void update([int speed]) {
     Point next = isRandom ? nextPosRandom() : nextPosOrdered(_curPos);
     if (_curPos.x < 0) _curPos = Point(0, _curPos.y);
     Color newColor = isRandom ? randomColor() : nextColor(

lib/src/03-VariableTimestep.dart

@@ -1,4 +1,5 @@
 import 'dart:html';
+
 import 'package:browserloop/game/Game.dart';
 import 'package:browserloop/game/LoopExample.dart';
 
@@ -7,7 +8,8 @@ import 'package:browserloop/game/LoopExample.dart';
 /// Perhaps one of the most widely used loops
 /// in games for many years. Many game frameworks
 /// make use of a loop similar to this.
-class VariableTimestep implements LoopExample {
+class VariableTimestep implements LoopExample, VariableUpdates {
+  double _COLORSWITCHSPEED = 1.0;
   Game game;
   num id;
   Stopwatch elapsed = new Stopwatch();
@@ -16,14 +18,21 @@ class VariableTimestep implements LoopExample {
 
   void eventloop(num time) {
     int dt = elapsed.elapsedMilliseconds;
-    game.update(dt);
+    
+    // Multiply by dt, so that the color switching speed is the same,
+    // regardless of the time it took to compute this update
+    int colorSwitchspeed = (_COLORSWITCHSPEED / 10 * dt).toInt();
+
+    game.update(colorSwitchspeed);
     game.draw();
     elapsed.reset();
 
     id = window.requestAnimationFrame(eventloop);
   }
 
-  // Starting and stopping the loop for the example page
+
+  // CONTROLS ON THE EXAMPLE PAGE
+  // NOT NECESSARY FOR LOOP ITSELF
   void stop() {
     elapsed.stop();
     window.cancelAnimationFrame(id);
@@ -34,4 +43,9 @@ class VariableTimestep implements LoopExample {
     elapsed.reset();
     window.requestAnimationFrame(eventloop);
   }
+
+  @override
+  void setUpdates(double updateRate) {
+    _COLORSWITCHSPEED = 1000 / updateRate;
+  }
 }