Merge pull request #1672 from vlidholt/master

Makes sprite physics bodies scalable

examples/game/test_physics.dart

@@ -55,6 +55,7 @@ class TestBed extends NodeWithSize {
     _obstacle = new Sprite(_spriteSheet["ship.png"]);
     _obstacle.position = new Point(512.0, 800.0);
     _obstacle.size = new Size(64.0, 64.0);
+    _obstacle.scale = 2.0;
     _obstacle.physicsBody = new PhysicsBody(
       new PhysicsShapeCircle(Point.origin, 32.0),
       type: PhysicsBodyType.static,
@@ -71,6 +72,12 @@ class TestBed extends NodeWithSize {
     ]);
     _obstacle.actions.run(new ActionRepeatForever(seq));
 
+    seq = new ActionSequence([
+      new ActionTween((a) => _obstacle.scale = a, 1.0, 2.0, 2.0, easeInOut),
+      new ActionTween((a) => _obstacle.scale = a, 2.0, 1.0, 2.0, easeInOut)
+    ]);
+    _obstacle.actions.run(new ActionRepeatForever(seq));
+
     addChild(_physicsNode);
 
     userInteractionEnabled = true;

packages/flutter_sprites/lib/src/node.dart

@@ -251,6 +251,12 @@ class Node {
 
   void set scale(double scale) {
     assert(scale != null);
+
+    if (_physicsBody != null && parent is PhysicsNode) {
+      PhysicsNode physicsNode = parent;
+      physicsNode._updateScale(this.physicsBody, scale);
+    }
+
     _scaleX = _scaleY = scale;
     invalidateTransformMatrix();
   }
@@ -262,6 +268,8 @@ class Node {
 
   void set scaleX(double scaleX) {
     assert(scaleX != null);
+    assert(physicsBody == null);
+
     _scaleX = scaleX;
     invalidateTransformMatrix();
   }
@@ -273,6 +281,8 @@ class Node {
 
   void set scaleY(double scaleY) {
     assert(scaleY != null);
+    assert(physicsBody == null);
+
     _scaleY = scaleY;
     invalidateTransformMatrix();
   }

packages/flutter_sprites/lib/src/physics_body.dart

@@ -45,6 +45,8 @@ class PhysicsBody {
   Vector2 _targetPosition;
   double _targetAngle;
 
+  double _scale;
+
   Object tag;
 
   final PhysicsShape shape;
@@ -294,6 +296,9 @@ class PhysicsBody {
   void _attach(PhysicsNode physicsNode, Node node) {
     assert(_attached == false);
 
+    // Update scale
+    _scale = node.scale;
+
     // Create BodyDef
     box2d.BodyDef bodyDef = new box2d.BodyDef();
     bodyDef.linearVelocity = new Vector2(linearVelocity.dx, linearVelocity.dy);
@@ -318,6 +323,24 @@ class PhysicsBody {
     // Create Body
     _body = physicsNode.b2World.createBody(bodyDef);
 
+    _createFixtures(physicsNode);
+
+    _body.userData = this;
+
+    _physicsNode = physicsNode;
+    _node = node;
+
+    _attached = true;
+
+    // Attach any joints
+    for (PhysicsJoint joint in _joints) {
+      if (joint.bodyA._attached && joint.bodyB._attached) {
+        joint._attach(physicsNode);
+      }
+    }
+  }
+
+  void _createFixtures(PhysicsNode physicsNode) {
     // Create FixtureDef
     box2d.FixtureDef fixtureDef = new box2d.FixtureDef();
     fixtureDef.friction = friction;
@@ -339,19 +362,6 @@ class PhysicsBody {
       box2d.Fixture fixture = _body.createFixtureFromFixtureDef(fixtureDef);
       fixture.userData = physicsShape;
     }
-    _body.userData = this;
-
-    _physicsNode = physicsNode;
-    _node = node;
-
-    _attached = true;
-
-    // Attach any joints
-    for (PhysicsJoint joint in _joints) {
-      if (joint.bodyA._attached && joint.bodyB._attached) {
-        joint._attach(physicsNode);
-      }
-    }
   }
 
   void _detach() {
@@ -361,13 +371,26 @@ class PhysicsBody {
     }
   }
 
+  void _updateScale(PhysicsNode physicsNode) {
+    // Destroy old fixtures
+    for (box2d.Fixture fixture = _body.getFixtureList(); fixture != null; fixture = fixture.getNext()) {
+      _body.destroyFixture(fixture);
+    }
+
+    // Make sure we create new b2Shapes
+    shape._invalidate();
+
+    // Create new fixtures
+    _createFixtures(physicsNode);
+  }
+
   void _addB2Shapes(PhysicsNode physicsNode, PhysicsShape shape, List<box2d.Shape> b2Shapes, List<PhysicsShape> physicsShapes) {
     if (shape is PhysicsShapeGroup) {
       for (PhysicsShape child in shape.shapes) {
         _addB2Shapes(physicsNode, child, b2Shapes, physicsShapes);
       }
     } else {
-      b2Shapes.add(shape.getB2Shape(physicsNode));
+      b2Shapes.add(shape.getB2Shape(physicsNode, _scale));
       physicsShapes.add(shape);
     }
   }

packages/flutter_sprites/lib/src/physics_node.dart

@@ -181,6 +181,14 @@ class PhysicsNode extends Node {
     body._body.setAwake(true);
   }
 
+  void _updateScale(PhysicsBody body, double scale) {
+    body._scale = scale;
+
+    if (body._attached) {
+      body._updateScale(this);
+    }
+  }
+
   void addChild(Node node) {
     super.addChild(node);
     if (node.physicsBody != null) {

packages/flutter_sprites/lib/src/physics_shape.dart

@@ -6,14 +6,18 @@ abstract class PhysicsShape {
 
   Object userObject;
 
-  box2d.Shape getB2Shape(PhysicsNode node) {
+  box2d.Shape getB2Shape(PhysicsNode node, double scale) {
     if (_b2Shape == null) {
-      _b2Shape = _createB2Shape(node);
+      _b2Shape = _createB2Shape(node, scale);
     }
     return _b2Shape;
   }
 
-  box2d.Shape _createB2Shape(PhysicsNode node);
+  box2d.Shape _createB2Shape(PhysicsNode node, double scale);
+
+  void _invalidate() {
+    _b2Shape = null;
+  }
 }
 
 class PhysicsShapeCircle extends PhysicsShape {
@@ -22,11 +26,11 @@ class PhysicsShapeCircle extends PhysicsShape {
   final Point point;
   final double radius;
 
-  box2d.Shape _createB2Shape(PhysicsNode node) {
+  box2d.Shape _createB2Shape(PhysicsNode node, double scale) {
     box2d.CircleShape shape = new box2d.CircleShape();
-    shape.p.x = point.x / node.b2WorldToNodeConversionFactor;
-    shape.p.y = point.y / node.b2WorldToNodeConversionFactor;
-    shape.radius = radius / node.b2WorldToNodeConversionFactor;
+    shape.p.x = scale * point.x / node.b2WorldToNodeConversionFactor;
+    shape.p.y = scale * point.y / node.b2WorldToNodeConversionFactor;
+    shape.radius = scale * radius / node.b2WorldToNodeConversionFactor;
     return shape;
   }
 }
@@ -36,12 +40,12 @@ class PhysicsShapePolygon extends PhysicsShape {
 
   final List<Point> points;
 
-  box2d.Shape _createB2Shape(PhysicsNode node) {
+  box2d.Shape _createB2Shape(PhysicsNode node, double scale) {
     List<Vector2> vectors = [];
     for (Point point in points) {
       Vector2 vec = new Vector2(
-        point.x / node.b2WorldToNodeConversionFactor,
-        point.y / node.b2WorldToNodeConversionFactor
+        scale * point.x / node.b2WorldToNodeConversionFactor,
+        scale * point.y / node.b2WorldToNodeConversionFactor
       );
       vectors.add(vec);
     }
@@ -65,14 +69,14 @@ class PhysicsShapeBox extends PhysicsShape {
   final Point center;
   final double rotation;
 
-  box2d.Shape _createB2Shape(PhysicsNode node) {
+  box2d.Shape _createB2Shape(PhysicsNode node, double scale) {
     box2d.PolygonShape shape = new box2d.PolygonShape();
     shape.setAsBox(
-      width / node.b2WorldToNodeConversionFactor,
-      height / node.b2WorldToNodeConversionFactor,
+      scale * width / node.b2WorldToNodeConversionFactor,
+      scale * height / node.b2WorldToNodeConversionFactor,
       new Vector2(
-        center.x / node.b2WorldToNodeConversionFactor,
-        center.y / node.b2WorldToNodeConversionFactor
+        scale * center.x / node.b2WorldToNodeConversionFactor,
+        scale * center.y / node.b2WorldToNodeConversionFactor
       ),
       radians(rotation)
     );
@@ -86,12 +90,12 @@ class PhysicsShapeChain extends PhysicsShape {
   final List<Point> points;
   final bool loop;
 
-  box2d.Shape _createB2Shape(PhysicsNode node) {
+  box2d.Shape _createB2Shape(PhysicsNode node, double scale) {
     List<Vector2> vectors = [];
     for (Point point in points) {
       Vector2 vec = new Vector2(
-        point.x / node.b2WorldToNodeConversionFactor,
-        point.y / node.b2WorldToNodeConversionFactor
+        scale * point.x / node.b2WorldToNodeConversionFactor,
+        scale * point.y / node.b2WorldToNodeConversionFactor
       );
       vectors.add(vec);
     }
@@ -111,16 +115,16 @@ class PhysicsShapeEdge extends PhysicsShape {
   final Point pointA;
   final Point pointB;
 
-  box2d.Shape _createB2Shape(PhysicsNode node) {
+  box2d.Shape _createB2Shape(PhysicsNode node, double scale) {
     box2d.EdgeShape shape = new box2d.EdgeShape();
     shape.set(
       new Vector2(
-        pointA.x / node.b2WorldToNodeConversionFactor,
-        pointA.y / node.b2WorldToNodeConversionFactor
+        scale * pointA.x / node.b2WorldToNodeConversionFactor,
+        scale * pointA.y / node.b2WorldToNodeConversionFactor
       ),
       new Vector2(
-        pointB.x / node.b2WorldToNodeConversionFactor,
-        pointB.y / node.b2WorldToNodeConversionFactor
+        scale * pointB.x / node.b2WorldToNodeConversionFactor,
+        scale * pointB.y / node.b2WorldToNodeConversionFactor
       )
     );
     return shape;
@@ -133,7 +137,13 @@ class PhysicsShapeGroup extends PhysicsShape {
 
   final List<PhysicsShape> shapes;
 
-  box2d.Shape _createB2Shape(PhysicsNode node) {
+  box2d.Shape _createB2Shape(PhysicsNode node, double scale) {
     return null;
   }
+
+  void _invalidate() {
+    for (PhysicsShape shape in shapes) {
+      shape._invalidate();
+    }
+  }
 }