Drawing a surface in the wireframe is a good way to check the structure of the triangle mesh forming the surface. In the context of video synthesis, it can be seen as a kind of special effect. But normally we are interested in drawing a 3D object as solid surfaces, which means that all its triangles are drawn as solid polygons.

To draw a solid sphere, just replace the sphere.drawWireframe() command in draw3d() with the following command:

sphere.draw();

On running the project, you will see the sphere as a white circle, as shown in the following screenshot:

This is a solid sphere without shading.

The reason for the sphere to look like a flat figure is that each triangle in the sphere is drawn as a solid white polygon without using information of its orientation for shading.

To obtain a sphere that looks more natural, let's implement the shading of its surface.