node/ui: limit amount of selectable nodes for performance

app/widget/nodeparamview/nodeparamview.cpp

@@ -697,13 +697,20 @@ void NodeParamView::QueueKeyframePositionUpdate()
 
 void NodeParamView::AddContext(Node *ctx)
 {
+  NodeParamViewContext *item = GetContextItemFromContext(ctx);
+
+  // TEMP: Creating many NPV items is EXTREMELY slow so limit to one item per context for now.
+  //       I have a better solution in the works to use one UI for several nodes, but I haven't
+  //       done it yet, and this can severely affect productivity.
+  if (item->GetContexts().size() == 1) {
+    return;
+  }
+
   // Queued so that if any further work is done in connecting this node to the context, it'll be
   // done before our sorting function is called
   connect(ctx, &Node::NodeAddedToContext, this, &NodeParamView::NodeAddedToContext, Qt::QueuedConnection);
   connect(ctx, &Node::NodeRemovedFromContext, this, &NodeParamView::NodeRemovedFromContext, Qt::QueuedConnection);
 
-  NodeParamViewContext *item = GetContextItemFromContext(ctx);
-
   item->AddContext(ctx);
   item->setVisible(true);
 

app/widget/nodeview/nodeview.cpp

@@ -44,6 +44,7 @@
 namespace olive {
 
 const double NodeView::kMinimumScale = 0.1;
+const int NodeView::kMaximumContexts = 10;
 
 NodeView::NodeView(QWidget *parent) :
   HandMovableView(parent),
@@ -102,6 +103,10 @@ void NodeView::SetContexts(const QVector<Node*> &nodes)
 
   // Add contexts that are now in the list
   foreach (Node *n, nodes) {
+    if (scene_.context_map().size() >= kMaximumContexts) {
+      break;
+    }
+
     if (!contexts_.contains(n)) {
       AddContext(n);
     }

app/widget/nodeview/nodeview.h

@@ -235,6 +235,8 @@ private:
 
   static const double kMinimumScale;
 
+  static const int kMaximumContexts;
+
 private slots:
   /**
    * @brief Receiver for when the scene's selected items change