Integration of point-based rendering into a common scene graph system

Current scene graph systems support a large amount of useful features and algorithms to enhance the quality and rendering speed of 3D applications. But they lack the integration of point-based objects that can be handled in the same way as triangle-based polygon objects. In this paper we present an extension to a common scene graph system which allows the rendering of point-based surfaces. The point objects can be inserted at arbitrary positions in the scene graph and are rendered together with common polygon objects in the same pass. The rendering of these objects is done by using only point primitives that are generally faster to render than ordinary (textured) triangles because only one vertex per primitive is necessary. To avoid aliasing effects, a filtering method similar to surface splatting is used. To reduce the rendering time for very complex objects, a continuous LOD mechanism combined with hierarchical backface culling by visibility cones is provided by the underlying data structure. Finally, our extension consists of a new OpenSG specific NodeCore class, a utility class for an easier creation of the data structure, and the shader programs.