NodeSystemClassInterface Implementation

Table of Contents

• About
• Methods

About

A node system class defines a set of methods to customize the behaviour of node systems and node templates. Whenever a NodeTemplate is instantiated to a NodeSystem, this process goes through a NodeSystemClass. Also only NodeSystems which use the same class can be used together.

Note

The instance of maxon::nodes::NodeSystemClassInterface must be registered in maxon::nodes::NodeSpaceInterface::Init(). See NodeSpaceInterface Implementation.

Methods

These methods allow to filter nodes that can be used in the node system.

• maxon::nodes::NodeSystemClassInterface::SupportsImpl(): Returns true if this node system class supports the instantiation of the given node template.
• maxon::nodes::NodeSystemClassInterface::InstantiateImpl(): Instantiates the given template.
• maxon::nodes::NodeSystemClassInterface::SupportsVariant(): Returns true if this node system class supports the given variant.
• maxon::nodes::NodeSystemClassInterface::SubstituteVariant(): Substitutes an unsupported variant.

static maxon::Id g_nodeSystemClassExampleID = maxon::Id("net.maxonexample.class.examplenodeclass");
 
class ExampleNodeSystemClassImpl : public maxon::Component<ExampleNodeSystemClassImpl, maxon::nodes::NodeSystemClassInterface>
{
  MAXON_COMPONENT(FINAL, maxon::nodes::BaseCoreNodesNodeSystemClass().GetClass());
 
public:
  MAXON_METHOD maxon::Result<maxon::Bool> SupportsImpl(const maxon::nodes::NodeTemplate& templ) const
  {
    const maxon::Id& id = templ.GetId();
    if (id == maxon::Id("net.maxon.node.arithmetic") || id == maxon::Id("net.maxon.node.scale"))
    {
      return true;
    }
    return super.SupportsImpl(templ);
  }
 
 
  MAXON_METHOD maxon::Result<maxon::Bool> SupportsVariant(const maxon::nodes::NodeTemplate& templ, const maxon::Block<const maxon::Id>& variant) const
  {
    return *variant.GetLast() != maxon::Id("net.maxon.parametrictype.col<4,float>");
  }
 
  MAXON_METHOD maxon::Result<maxon::Id> SubstituteVariant(const maxon::nodes::NodeTemplate& templ, const maxon::Block<const maxon::Id>& variant, const maxon::Block<const maxon::Id>& options) const
  {
    if (*variant.GetLast() == maxon::Id("net.maxon.parametrictype.col<4,float>"))
    {
      return maxon::Id("net.maxon.parametrictype.col<3,float>");
    }
    return { };
  }
};
 
MAXON_COMPONENT_CLASS_REGISTER(ExampleNodeSystemClassImpl, g_nodeSystemClassExampleID);

Further methods are:

• maxon::nodes::NodeSystemClassInterface::GetGraphAttribute(): Returns the GraphAttribute which node systems of this class use for the given ID.
• maxon::nodes::NodeSystemClassInterface::GetGraphAttributeFlags(): Returns the maxon::GraphAttributeInterface::FLAGS to use for the given ID.
• maxon::nodes::NodeSystemClassInterface::GetId(): Returns a unique identifier for this node system class.
• maxon::nodes::NodeSystemClassInterface::CreateNodeSystem(): Creates a new compound node system.
• maxon::nodes::NodeSystemClassInterface::FinalizeModification(): Runs finalization steps at the end of a modification.
• maxon::nodes::NodeSystemClassInterface::NeedsAttribute(): Returns true if the node system class needs the derivation of the given attribute.
• maxon::nodes::NodeSystemClassInterface::Convert(): Converts a value to the given type.

  // This example creates a new NodesGraphModelRef.
  
  maxon::AssetRepositoryRef repository = maxon::AssetInterface::GetBuiltinRepository();
  maxon::nodes::MutableRoot root = maxon::nodes::CoreNodesNodeSystemClass().CreateNodeSystem(repository) iferr_return;
  maxon::nodes::NodeSystem  sys  = root.EndModification(maxon::NO_VALUE, maxon::nodes::NodeSystemInterface::FINALIZE_FLAGS::NONE) iferr_return;
 
  const auto filter = maxon::nodes::NodeSystemManagerInterface::FILTER::INCLUDE_INNER | maxon::nodes::NodeSystemManagerInterface::FILTER::INCLUDE_HIDDEN;
 
  const auto nodesGraphModelClass = maxon::nodes::NodesGraphModelClass();
  maxon::nodes::NodesGraphModelRef nodesGraphModel = nodesGraphModelClass.Create() iferr_return;
 
  nodesGraphModel.Init(sys, repository, filter, true) iferr_return;