“I’ll sit and see if that small sailing cloud Will hit or miss the moon.”
Intersection testing is often used in computer graphics. We may wish to determine whether two objects collide, or to find the distance to the ground so we can keep the camera at a constant height. Another important use is finding whether an object should be sent down the pipeline at all. All these operations can be performed with intersection tests. In this chapter, we cover the most common ray/object and object/object intersection tests.
In collision detection algorithms, which are also built upon hierarchies, the system must decide whether or not two primitive objects collide. These objects include triangles, spheres, ...