Real-Time Rendering, Third Edition, 3rd Edition

i

i

i

i

i

i

i

i

790 16. Intersection Test Methods

Figure 16.31. In the left figure, a sphere moves towards a polygon. In the right figure,

a ray shoots at an “inflated” version of the polygon. The two intersection tests are

equivalent.

ray against this volume’s parts: First, the polygon facing the ray is tested,

then the edge cylinders are tested against the ray, and finally, the vertex

spheres are tested.

Thinking about this puffy object gives insight as to why a polygon is

most efficiently tested by using the order of area, then edges, then vertices.

The polygon in this puffy object that faces the sphere is not covered by the

object’s cylinders and spheres, so testing ...