disambiguated whether NodeParam::parent() would return a Node* or a QObject*

Old code assumes that a NodeParam's parent will always be a Node. The function
has been separated off and tweaked in the event that this is not the case.

app/render/backend/audiorenderworker.cpp

@@ -15,7 +15,7 @@ void AudioRenderWorker::SetParameters(const AudioRenderingParams &audio_params)
 QVariant AudioRenderWorker::RenderAsSibling(NodeDependency dep)
 {
   NodeOutput* output = dep.node();
-  Node* node = output->parent();
+  Node* node = output->parentNode();
   QList<NodeInput*> connected_inputs;
   QVariant value;
 
@@ -66,7 +66,7 @@ void AudioRenderWorker::CloseInternal()
 
 QVariant AudioRenderWorker::RenderBlock(NodeOutput* output, const TimeRange &range)
 {
-  QList<Block*> active_blocks = ValidateBlockRange(static_cast<Block*>(output->parent()), range);
+  QList<Block*> active_blocks = ValidateBlockRange(static_cast<Block*>(output->parentNode()), range);
 
   // All these blocks will need to output to a buffer so we create one here
   QByteArray block_range_buffer(audio_params_.time_to_bytes(range.length()), 0);

app/render/backend/opengl/openglbackend.cpp

@@ -88,7 +88,7 @@ bool OpenGLBackend::TraverseCompiling(Node *n)
       // Check if we have a shader or not
       if (shader_cache_.GetShader(connected_output) == nullptr)  {
         // Since we don't have a shader, compile one now
-        QString node_code = connected_output->parent()->Code(connected_output);
+        QString node_code = connected_output->parentNode()->Code(connected_output);
 
         // If the node has no code, it mustn't be GPU accelerated
         if (!node_code.isEmpty()) {
@@ -126,7 +126,7 @@ bool OpenGLBackend::TraverseCompiling(Node *n)
         }
       }
 
-      if (!TraverseCompiling(connected_output->parent())) {
+      if (!TraverseCompiling(connected_output->parentNode())) {
         return false;
       }
     }

app/render/backend/opengl/openglshadercache.cpp

@@ -10,7 +10,7 @@ OpenGLShaderCache::OpenGLShaderCache()
 QString OpenGLShaderCache::GenerateShaderID(NodeOutput *output)
 {
   // Creates a unique identifier for this specific node and this specific output
-  return QString("%1:%2").arg(output->parent()->id(), output->id());
+  return QString("%1:%2").arg(output->parentNode()->id(), output->id());
 }
 
 void OpenGLShaderCache::Clear()

app/render/backend/opengl/openglworker.cpp

@@ -86,7 +86,7 @@ void OpenGLWorker::ParametersChangedEvent()
 QVariant OpenGLWorker::RunNodeAccelerated(NodeOutput *out)
 {
   OpenGLShaderPtr shader = shader_cache_->GetShader(out);
-  Node* node = out->parent();
+  Node* node = out->parentNode();
 
   // Create the output texture
   OpenGLTexturePtr output = std::make_shared<OpenGLTexture>();

app/render/backend/renderworker.cpp

@@ -171,7 +171,7 @@ QList<NodeInput*> RenderWorker::ProcessNodeInputsForTime(Node *n, const TimeRang
 QVariant RenderWorker::ProcessNodeNormally(const NodeDependency& dep)
 {
   NodeOutput* output = dep.node();
-  Node* node = dep.node()->parent();
+  Node* node = dep.node()->parentNode();
 
   //qDebug() << "Processing" << node->id();
 

app/render/backend/videorenderworker.cpp

@@ -21,7 +21,7 @@ void VideoRenderWorker::RenderInternal(const NodeDependency& path)
   // Get hash of node graph
   // We use SHA-1 for speed (benchmarks show it's the fastest hash available to us)
   QCryptographicHash hasher(QCryptographicHash::Sha1);
-  HashNodeRecursively(&hasher, path.node()->parent(), path.in());
+  HashNodeRecursively(&hasher, path.node()->parentNode(), path.in());
   QByteArray hash = hasher.result();
 
   if (frame_cache_->HasHash(hash)) {
@@ -123,7 +123,7 @@ void VideoRenderWorker::CloseInternal()
 QVariant VideoRenderWorker::RenderAsSibling(NodeDependency dep)
 {
   NodeOutput* output = dep.node();
-  Node* original_node = output->parent();
+  Node* original_node = output->parentNode();
   Node* node;
   rational time = dep.in();
   QVariant value;