Rendering regions in Unicon
This section describes a control structure called rendering regions, which was added to Unicon while writing this book. Since this feature is new, we will look at it in some detail. The rendering region control structure has been on Unicon’s to-do list for a long time but adding a control structure can be a bit difficult, especially if the semantics are non-trivial, so it took writing this chapter to get around to it. First, though, we need to set the scene.
Rendering 3D graphics from a display list
Unicon’s 3D graphics facilities specify what is to be drawn via a series of calls to a set of built-in functions, and an underlying runtime system renders code written in C and OpenGL that draws the scene as many times per second as possible. The Unicon functions and C render code communicate using a display list. Mainly, the Unicon functions place primitives on the end of the display list, and the rendering code traverses the display list...
