Modifying Nodes with Interfaces

Table of Contents

• Import Adapter Interface
  • UI Conversion Interface
  • Material Exchange Interface

Describes how to modify nodes with the help of purpose-bound interfaces.

Import Adapter Interface

Despite its name, the ImportAdapterInterface allows both for modifying nodes on serialization and deserialization processes. It provides two methods to be overridden: the method BeforeWrite(), which is being called before a node is written to a file, and the method AfterRead(), which is being called after a node has been read from file. With this interface it's possible define version translation interfaces between node graphs that have been created with different revisions of a plugin.

 
MAXON_INTERNED_ID_LOCAL("net.maxonexample.handbook.adapter.version", MyAdapterVersion);
 
class MyAdapterImpl : public maxon::Component<MyAdapterImpl, maxon::nodes::ImportAdapterInterface>
{
  MAXON_COMPONENT(FINAL);
 
public:
  static constexpr maxon::Int VERSION = 1;
 
  static MAXON_METHOD maxon::Result<maxon::Bool> BeforeWrite(maxon::nodes::SerializationNodeData& node)
  {
    iferr_scope;
 
    if (node.GetBaseTemplate().first == maxon::Id("net.maxonexample.handbook.noderenderer.usernode"))
    {
      // We have found a Value node. Add a version tag.
      node.GetAttributes().Insert(MyAdapterVersion, maxon::Data(VERSION)) iferr_return;
    }
    else if (node.GetPath().GetKind() == maxon::NODE_KIND::NODE)
    {
      // Recurse into nested nodes.
      node.GetChildren(BeforeWrite) iferr_return;
    }
    return true;
  }
 
  static MAXON_METHOD maxon::Result<maxon::Bool> AfterRead(maxon::nodes::SerializationNodeData& node)
  {
    iferr_scope;
 
    if (node.GetBaseTemplate().first == maxon::Id("net.maxonexample.handbook.noderenderer.usernode"))
    {
      // We have found a Value node. See if the version tag matches the current version.
      const maxon::Data* d = node.GetAttributes().FindValue(MyAdapterVersion);
      if (!d || maxon::ConstDataPtr(*d) != maxon::ConstDataPtr(VERSION))
      {
        // Version does not match. Do something about it
      }
    }
    else if (node.GetPath().GetKind() == maxon::NODE_KIND::NODE)
    {
      // Recurse into nested nodes.
      node.GetChildren(AfterRead) iferr_return;
    }
    return true;
  }
};

The adapter implementation has to be registered with the following macro:

MAXON_COMPONENT_OBJECT_REGISTER(MyAdapterImpl, maxon::nodes::ImportAdapters, "net.maxonexample.handbook.node.myadapter");

UI Conversion Interface

This interface allows for providing a custom classic UI for a given port type. This classic UI is then displayed in the Node Editor window. The interface is registered using the specific node identifier of the port that is being targeted. This identifier can be found in the description of a parameter under "Group Type Id"; for example when inspecting the type in the the Resource Editor.

Material Exchange Interface

See ExchangeMapper Material Export Manual