Bounding Box in frustum

To test if an Oriented Bounding Box (OBB) or an Axis Aligned Bounding Box (AABB) intersects a frustum, follow the same steps. First we have to be able to classify the box against a plane. A box and a plane can have one of three intersection states:

• The box is in front of the plane

• The box is behind the plane

• The box intersects the plane

Once we are able to classify a box to a plane, we need to loop through every plane of the frustum and classify the box against each plane. If the box is fully behind any of the six planes, there is no intersection. If the box is in front of every plane, it is contained within the frustum. Otherwise, the box intersects the frustum:

Getting ready

In this section, we are going to implement two Classify functions. One to classify an OBB against a plane, and one to classify an AABB against a plane. The Classify functions will have the following return values:

• If the box is behind the plane, the negative distance is returned

• If the box is in front...