Don't force joints to use the bodies world center as anchors

Signed-off-by: Roger Zanoni <roger.zanoni@openbossa.org>

Author: Roger Zanoni

src/box2ddistancejointitem.cpp

@@ -54,8 +54,8 @@ void Box2DDistanceJointItem::initialize()
 
     jointDef.Initialize(m_entityA->body(),
                         m_entityB->body(),
-                        m_entityA->body()->GetWorldCenter(),
-                        m_entityB->body()->GetWorldCenter());
+                        m_anchorA.isNull() ? m_entityA->body()->GetWorldCenter() : b2Util::b2Vec(m_anchorA, m_scaleRatio),
+                        m_anchorB.isNull() ? m_entityB->body()->GetWorldCenter() : b2Util::b2Vec(m_anchorB, m_scaleRatio));
 
 
     m_joint = static_cast<b2DistanceJoint *>(m_worldPtr->CreateJoint(&jointDef));

src/box2djointitem.cpp

@@ -71,3 +71,23 @@ void Box2DJointItem::setCollideConnected(const bool &collideConnected)
         emit collideConnectedChanged();
     }
 }
+
+void Box2DJointItem::setAnchorA(const QPointF &anchorA)
+{
+    if (m_anchorA == anchorA)
+        return;
+
+    m_anchorA = anchorA;
+
+    emit anchorAChanged();
+}
+
+void Box2DJointItem::setAnchorB(const QPointF &anchorB)
+{
+    if (m_anchorB == anchorB)
+        return;
+
+    m_anchorB = anchorB;
+
+    emit anchorBChanged();
+}

src/box2djointitem.h

@@ -35,6 +35,8 @@ class Box2DJointItem : public Box2DBaseItem
     Q_PROPERTY(Entity *entityA READ entityA WRITE setEntityA NOTIFY entityAChanged)
     Q_PROPERTY(Entity *entityB READ entityB WRITE setEntityB NOTIFY entityBChanged)
     Q_PROPERTY(bool collideConnected READ collideConnected WRITE setCollideConnected NOTIFY collideConnectedChanged)
+    Q_PROPERTY(QPointF anchorA READ anchorA WRITE setAnchorA NOTIFY anchorAChanged)
+    Q_PROPERTY(QPointF anchorB READ anchorB WRITE setAnchorB NOTIFY anchorBChanged)
 
 public:
     Box2DJointItem(Scene *parent = 0);
@@ -49,16 +51,26 @@ class Box2DJointItem : public Box2DBaseItem
     bool collideConnected() const;
     void setCollideConnected(const bool &collideConnected);
 
+    QPointF anchorA() const { return m_anchorA; }
+    void setAnchorA(const QPointF &anchorA);
+
+    QPointF anchorB() const { return m_anchorB; }
+    void setAnchorB(const QPointF &anchorB);
+
 signals:
     void entityAChanged();
     void entityBChanged();
     void collideConnectedChanged();
+    void anchorAChanged();
+    void anchorBChanged();
 
 protected:
     Entity *m_entityA;
     Entity *m_entityB;
     bool m_collideConnected;
     b2Joint *m_joint;
+    QPointF m_anchorA;
+    QPointF m_anchorB;
 };
 
 #endif /* _BOX2DJOINTITEM_H_ */