use strings to connect nodes

This makes the node system somewhat more high-level with the intent of making
working with them far more flexible and stable. By making the architecture more
abstracted, it becomes far less rigid which should allow us to do even more
with it and make it much less crash prone.

app/node/block/transition/transition.h

@@ -33,9 +33,6 @@ public:
 
   virtual Type type() const override;
 
-  NodeInput* out_block_input() const;
-  NodeInput* in_block_input() const;
-
   virtual void Retranslate() override;
 
   rational in_offset() const;
@@ -50,7 +47,11 @@ public:
 
   virtual void Hash(QCryptographicHash& hash, const rational &time) const override;
 
-  virtual NodeValueTable Value(NodeValueDatabase &value) const override;
+  virtual NodeValueTable Value(const QString& output, NodeValueDatabase &value) const override;
+
+  static const QString kOutBlockInput;
+  static const QString kInBlockInput;
+  static const QString kCurveInput;
 
 protected:
   virtual void ShaderJobEvent(NodeValueDatabase &value, ShaderJob& job) const;
@@ -59,6 +60,10 @@ protected:
 
   double TransformCurve(double linear) const;
 
+  virtual void InputConnectedEvent(const QString& input, int element, const NodeOutput& output) override;
+
+  virtual void InputDisconnectedEvent(const QString& input, int element, const NodeOutput& output) override;
+
 private:
   enum CurveType {
     kLinear,
@@ -70,25 +75,10 @@ private:
 
   void InsertTransitionTimes(AcceleratedJob* job, const double& time) const;
 
-  NodeInput* out_block_input_;
-
-  NodeInput* in_block_input_;
-
-  NodeInput* curve_input_;
-
   Block* connected_out_block_;
 
   Block* connected_in_block_;
 
-private slots:
-  void OutBlockConnected(Node* node);
-
-  void OutBlockDisconnected();
-
-  void InBlockConnected(Node* node);
-
-  void InBlockDisconnected();
-
 };
 
 }