Adds a SpriteWidget and simplifies sample game setup

R=abarth@chromium.org

Review URL: https://codereview.chromium.org/1197493002.

examples/game/lib/game_demo.dart

@@ -5,7 +5,5 @@ import 'dart:math' as Math;
 import 'package:vector_math/vector_math_64.dart';
 import 'sprites.dart';
 import 'package:box2d/box2d.dart';
-import 'package:sky/rendering/box.dart';
 
 part 'game_demo_world.dart';
-part 'game_demo_box.dart';

examples/game/lib/game_demo_box.dart

-part of game;
-
-const double _steeringThreshold = 0.0;
-const double _steeringMax = 150.0;
-
-class GameDemoBox extends SpriteBox {
-
-  GameDemoBox(GameDemoWorld game) : super(game, SpriteBoxTransformMode.letterbox);
-
-  GameDemoWorld get _gameWorld => this.rootNode;
-
-  // Handle pointers
-  int _firstPointer = -1;
-  int _secondPointer = -1;
-  Point _firstPointerDownPos;
-
-//  void handleEvent(Event event, BoxHitTestEntry entry) {
-//    if (event is PointerEvent) {
-//      Point pointerPos = new Point(event.x, event.y);
-//      int pointer = event.pointer;
-//
-//      switch (event.type) {
-//        case 'pointerdown':
-//          if (_firstPointer == -1) {
-//            // Assign the first pointer
-//            _firstPointer = pointer;
-//            _firstPointerDownPos = pointerPos;
-//          }
-//          else if (_secondPointer == -1) {
-//            // Assign second pointer
-//            _secondPointer = pointer;
-//            _gameWorld.controlFire();
-//          }
-//          else {
-//            // There is a pointer used for steering, let's fire instead
-//            _gameWorld.controlFire();
-//          }
-//          break;
-//        case 'pointermove':
-//          if (pointer == _firstPointer) {
-//            // Handle turning control
-//            double joystickX = 0.0;
-//            double deltaX = pointerPos.x - _firstPointerDownPos.x;
-//            if (deltaX > _steeringThreshold || deltaX < -_steeringThreshold) {
-//              joystickX = (deltaX - _steeringThreshold)/(_steeringMax - _steeringThreshold);
-//              if (joystickX > 1.0) joystickX = 1.0;
-//              if (joystickX < -1.0) joystickX = -1.0;
-//            }
-//
-//            double joystickY = 0.0;
-//            double deltaY = pointerPos.y - _firstPointerDownPos.y;
-//            if (deltaY > _steeringThreshold || deltaY < -_steeringThreshold) {
-//              joystickY = (deltaY - _steeringThreshold)/(_steeringMax - _steeringThreshold);
-//              if (joystickY > 1.0) joystickY = 1.0;
-//              if (joystickY < -1.0) joystickY = -1.0;
-//            }
-//
-//            _gameWorld.controlSteering(joystickX, joystickY);
-//          }
-//          break;
-//        case 'pointerup':
-//        case 'pointercancel':
-//          if (pointer == _firstPointer) {
-//            // Un-assign the first pointer
-//            _firstPointer = -1;
-//            _firstPointerDownPos = null;
-//            _gameWorld.controlSteering(0.0, 0.0);
-//          }
-//          else if (pointer == _secondPointer) {
-//            _secondPointer = -1;
-//          }
-//          break;
-//        default:
-//          break;
-//      }
-//    }
-//  }
-
-}

examples/game/lib/game_demo_world.dart

 part of game;
 
+const double _steeringThreshold = 0.0;
+const double _steeringMax = 150.0;
+
 // Random generator
 Math.Random _rand = new Math.Random();
 
@@ -357,7 +360,7 @@ class Laser extends Sprite {
     _movementVector = new Point(_movementVector.x + ship._movementVector[0], _movementVector.y + ship._movementVector[1]);
   }
 
-  bool move() {
+  void move() {
     position = pointAdd(position, _movementVector);
     _frameCount++;
   }

examples/game/lib/sprite_box.dart

@@ -14,7 +14,7 @@ class SpriteBox extends RenderBox {
   // Member variables
 
   // Root node for drawing
-  Node _rootNode;
+  NodeWithSize _rootNode;
 
   // Tracking of frame rate and updates
   double _lastTimeStamp;
@@ -23,8 +23,8 @@ class SpriteBox extends RenderBox {
 
   // Transformation mode
   SpriteBoxTransformMode transformMode;
-  double _systemWidth;
-  double _systemHeight;
+//  double _systemWidth;
+//  double _systemHeight;
 
   // Cached transformation matrix
   Matrix4 _transformMatrix;
@@ -33,7 +33,7 @@ class SpriteBox extends RenderBox {
 
   // Setup
 
-  SpriteBox(Node rootNode, [SpriteBoxTransformMode mode = SpriteBoxTransformMode.nativePoints, double width=1024.0, double height=1024.0]) {
+  SpriteBox(NodeWithSize rootNode, [SpriteBoxTransformMode mode = SpriteBoxTransformMode.nativePoints]) {
     assert(rootNode != null);
     assert(rootNode._spriteBox == null);
 
@@ -45,8 +45,8 @@ class SpriteBox extends RenderBox {
 
     // Setup transform mode
     transformMode = mode;
-    _systemWidth = width;
-    _systemHeight = height;
+//    _systemWidth = rootNode.size.width;
+//    _systemHeight = rootNode.size.height;
 
     _scheduleTick();
   }
@@ -60,10 +60,10 @@ class SpriteBox extends RenderBox {
 
   // Properties
 
-  double get systemWidth => _systemWidth;
-  double get systemHeight => _systemHeight;
+  double get systemWidth => rootNode.size.width;
+  double get systemHeight => rootNode.size.height;
 
-  Node get rootNode => _rootNode;
+  NodeWithSize get rootNode => _rootNode;
 
   void performLayout() {
     size = constraints.constrain(Size.infinite);
@@ -152,44 +152,49 @@ class SpriteBox extends RenderBox {
     double offsetX = 0.0;
     double offsetY = 0.0;
 
+    double systemWidth = rootNode.size.width;
+    double systemHeight = rootNode.size.height;
+
     switch(transformMode) {
       case SpriteBoxTransformMode.stretch:
-        scaleX = size.width/_systemWidth;
-        scaleY = size.height/_systemHeight;
+        scaleX = size.width/systemWidth;
+        scaleY = size.height/systemHeight;
         break;
       case SpriteBoxTransformMode.letterbox:
-        scaleX = size.width/_systemWidth;
-        scaleY = size.height/_systemHeight;
+        scaleX = size.width/systemWidth;
+        scaleY = size.height/systemHeight;
         if (scaleX > scaleY) {
           scaleY = scaleX;
-          offsetY = (size.height - scaleY * _systemHeight)/2.0;
+          offsetY = (size.height - scaleY * systemHeight)/2.0;
         }
         else {
           scaleX = scaleY;
-          offsetX = (size.width - scaleX * _systemWidth)/2.0;
+          offsetX = (size.width - scaleX * systemWidth)/2.0;
         }
         break;
       case SpriteBoxTransformMode.scaleToFit:
-        scaleX = size.width/_systemWidth;
-        scaleY = size.height/_systemHeight;
+        scaleX = size.width/systemWidth;
+        scaleY = size.height/systemHeight;
         if (scaleX < scaleY) {
           scaleY = scaleX;
-          offsetY = (size.height - scaleY * _systemHeight)/2.0;
+          offsetY = (size.height - scaleY * systemHeight)/2.0;
         }
         else {
           scaleX = scaleY;
-          offsetX = (size.width - scaleX * _systemWidth)/2.0;
+          offsetX = (size.width - scaleX * systemWidth)/2.0;
         }
         break;
       case SpriteBoxTransformMode.fixedWidth:
-        scaleX = size.width/_systemWidth;
+        scaleX = size.width/systemWidth;
         scaleY = scaleX;
-        _systemHeight = size.height/scaleX;
+        systemHeight = size.height/scaleX;
+        rootNode.size = new Size(systemWidth, systemHeight);
         break;
       case SpriteBoxTransformMode.fixedHeight:
-        scaleY = size.height/_systemHeight;
+        scaleY = size.height/systemHeight;
         scaleX = scaleY;
-        _systemWidth = size.width/scaleY;
+        systemWidth = size.width/scaleY;
+        rootNode.size = new Size(systemWidth, systemHeight);
         break;
       case SpriteBoxTransformMode.nativePoints:
         break;

examples/game/lib/sprite_widget.dart

+part of sprites;
+
+class SpriteWidget extends OneChildRenderObjectWrapper {
+
+  final NodeWithSize rootNode;
+  final SpriteBoxTransformMode transformMode;
+
+  SpriteWidget(this.rootNode, [this.transformMode = SpriteBoxTransformMode.letterbox]);
+
+  SpriteBox get root => super.root;
+
+  SpriteBox createNode() => new SpriteBox(rootNode, transformMode);
+
+  void syncRenderObject(SpriteWidget old) {
+    super.syncRenderObject(old);
+
+    // SpriteBox doesn't allow mutation of these properties
+    assert(rootNode == root.rootNode);
+    assert(transformMode == root.transformMode);
+  }
+}
\ No newline at end of file

examples/game/lib/sprites.dart

@@ -8,9 +8,11 @@ import 'package:sky/base/scheduler.dart' as scheduler;
 import 'package:sky/mojo/net/image_cache.dart' as image_cache;
 import 'package:sky/rendering/box.dart';
 import 'package:sky/rendering/object.dart';
+import 'package:sky/widgets/widget.dart';
 import 'package:vector_math/vector_math.dart';
 
 part 'sprite_box.dart';
+part 'sprite_widget.dart';
 part 'node.dart';
 part 'node_with_size.dart';
 part 'sprite.dart';

examples/game/main.dart

@@ -29,7 +29,7 @@ class GameDemoApp extends App {
 
   Widget build() {
     return new Stack([
-      new GameDemo(),
+      new SpriteWidget(new GameDemoWorld(_loader)),
 //      new StackPositionedChild(
 //        new Flex([
 //          new FlexExpandingChild(
@@ -49,12 +49,3 @@ class GameDemoApp extends App {
 }
 
 ImageMap _loader;
-
-class GameDemo extends OneChildRenderObjectWrapper {
-
-  GameDemo({ Widget child, Object key })
-  : super(child: child, key: key);
-
-  GameDemoBox get root { return super.root; }
-  GameDemoBox createNode() => new GameDemoBox(new GameDemoWorld(_loader));
-}