Drawing Models with Meshes
A model is an object drawn by the graphics engine. It contains a list of vertices that define its structure in terms of polygons. The collection of these connected polygons is known as a mesh. Each polygon inhabits a plane—this means that it is flat. A basic model with elementary shading appears faceted, such as that shown in Figure 4.4. This flat nature is hidden using differing materials, as we will discuss shortly:
Figure 4.4: A basic polygon mesh showing the flatness of each polygon
A polygon mesh is stored internally as a list of vertices and triangles. Triangles are chosen to represent each polygon over that of a square, as triangles require less storage and are faster to manipulate as they have one less vertex.
A typical data structure to hold a mesh is illustrated in the following diagram:
Figure 4.5: A vertex and triangle array used to define the triangles of a square
The example given stores...
