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Techniques for Working with Rendering Contexts

A rendering context is a container for state information. When you designate a rendering context as the current rendering context, subsequent OpenGL commands modify the drawable object associated with that context. The actual drawing surfaces are never really owned by the rendering context but are created, as needed, only when the rendering context is actually attached to a drawable object. You can attach multiple rendering contexts to a set of drawing surfaces. Each context draws with its own unique “pen” represented by its current state.

“Drawing to a Window or View,” “Drawing to the Full Screen,” and “Drawing Offscreen” show how to create a rendering context and attach it to a drawable object. As you'll recall, each of the Apple-specific OpenGL APIs provides a routine that's fairly easy to use for creating a rendering context. This chapter goes beyond creating rendering contexts; it shows how to set context parameters, update rendering contexts, and set up a shared context.

Contents:

Context Parameters
Updating a Rendering Context
Sharing Rendering Contexts
See Also

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