Graphics Reference
In-Depth Information
Chapter 3 introduces the mathematical and geometrical concepts necessary to
understand the material explored in the remaining chapters.
1.1.3
Chapter 4: Bounding Volumes
To accelerate collision queries, simple geometrical objects such as spheres and boxes
are initially used to represent objects of more complex nature. Only if the “simple”
bounding volumes (which are large enough to encapsulate complex objects) collide
are tests performed on the complex geometry. Chapter 4 describes several bounding
volume types, how to perform intersection tests on them, and how to fit a bounding
volume to a complex object.
1.1.4
Chapter 5: Basic Primitive Tests
Having introduced some intersection tests in the previous chapter, Chapter 5
describes, in detail, a large number of tests for determining intersection status and
distance between pairs of objects of varying types, including lines, rays, segments,
planes, triangles, polygons, spheres, boxes, cylinders, and polyhedra. Both static and
moving objects are considered in these tests.
1.1.5
Chapter 6: Bounding Volume Hierarchies
For large objects and for collections of objects, performance benefits can be had by
constructing hierarchies of bounding volumes over the object(s). Such hierarchies
provide quick identification of objects or parts of an object that cannot possibly par-
ticipate in a collision, allowing queries to restrict testing to a small number of objects
or object parts. Chapter 6 talks about desired characteristics of bounding volume hier-
archies and ways in which to construct and perform queries over them. The chapter
also explores efficient ways of representing these hierarchies.
1.1.6
Chapter 7: Spatial Partitioning
When a large number of objects are considered for collision, the objects must be
partitioned into small disjoint subgroups to facilitate fast tests (by avoiding the worst-
case quadratic behavior of testing all objects against all other objects). The bounding
volume hierarchies discussed in Chapter 6 represent one way of performing such
partitioning. Chapter 7 examines other partitioning approaches, based on grids, trees,
and object sorting.
