It is always exciting to create and view a large area, for example, the earth, in our OSG-based applications. A detailed terrain which can be paged dynamically and rendered smoothly is necessary for geographic information system (GIS). And that is what we are going to discuss in this chapter.
Early OSG developers may have heard of a simple utility named osgdem
in the core OSG releases at that time. It can build terrain data from original elevation and texture files and makes the results easy to merge into the scene graph. There is even a BlueMarbleViewer project showing how to build earth models with NASA's BlueMarble imagery using OpenSceneGraph 1.2 at http://www.andesengineering.com/BlueMarbleViewer/.
The osgdem
utility has grown to a complete terrain generation tool set named VirtualPlanetBuilder, which is also managed by Robert Osfield, the OSG team leader. And there are some other very good terrain builders and renderers. We will introduce one of them in this chapter—the...