The Interface

The Interface Abstraction

The Nodal Scene Interface is built around the concept of nodes. Each node has a unique handle to identify it and a type which describes its intended function in the scene. Nodes are abstract containers for data. The interpretation depends on the node type. Nodes can also be connected to each other to express relationships.

Data is stored on nodes as attributes. Each attribute has a name which is unique on the node and a type which describes the kind of data it holds (strings, integer numbers, floating point numbers, etc).

Relationships and data flow between nodes are represented as connections. Connections have a source and a destination. Both can be either a node or a specific attribute of a node. There are no type restrictions for connections in the interface itself. It is acceptable to connect attributes of different types or even attributes to nodes. The validity of such connections depends on the types of the nodes involved.

What we refer to as the ɴsɪ has two major components:

• Methods to create nodes, attributes and their connections.

• Node types understood by the renderer.

Much of the complexity and expressiveness of the interface comes from the supported nodes. The first part was kept deliberately simple to make it easy to support multiple ways of creating nodes. We will list a few of those in the following sections but this list is not meant to be final. New languages and file formats will undoubtedly be supported in the future.

APIs

• The C API
  • Context Handling
  • Arguments vs. Attributes
  • Passing Optional Arguments
  • Node Creation
  • Setting Attributes
  • Making Connections
  • Severing Connections
  • Evaluating Procedurals
  • Error Reporting
  • Rendering
• The C++ API
  • Creating a Context
  • Argument Passing
• The Rust API
  • Creating a Context
• The Lua API
  • API calls
  • Optional function arguments format
  • Evaluating a Lua script
  • Passing arguments to a Lua script
  • Reporting errors from a Lua script
• The Python API
• The Interface Stream
• Dynamic Library Procedurals
  • Entry Point
  • Procedural Description
  • Error Reporting
  • Preprocessor Macros