Handling Events and Selection

• Overview
• General Programming Model for Event Handling
• Inventor Event Handling
• How Nodes Handle Events: SoHandleEventAction
• Using Event Callback Nodes (Advanced)
• Sending Events Directly to the Application (Advanced)
• Selection
• Extended Selection

Chapter Objectives. After reading this chapter, you'll be able to do the following:

• Explain how Open Inventor handles input events
• Select objects in the scene using one of Inventor's built-in selection policies
• Implement your own selection policy by creating an event callback node
• Highlight selected objects in the scene
• Write selection callback functions to allow the application to perform certain operations when the selection list changes This chapter describes the Open Inventor event model, which provides a simple mechanism for passing events such as a key press or mouse movement to objects in the database for processing. In much the same way a window system passes events to its client windows, Inventor passes events to database objects that can handle them. Important concepts introduced in this chapter include the Inventor programming model for event handling and the use of the SoXtRenderArea, a widget that performs rendering and event handling on the Inventor database. The SoHandleEventAction is discussed in detail, as well as the concepts of event callback functions, the selection node, and highlighting.