Continuing with WebGL, we implemented directional lighting Phong shading–a combination of ambient, diffuse, and specular lighting. Each of these three components are computed as a function of the light and surface material properties.

Diffuse lighting is view independent since it is uniformly distributed. However, the orientation of the light impacts the intensity of its reflection. This is represented by the lambertian term (derived from Lambert’s cosine law). Specular lighting, being non-uniformly distributed, is view dependent.

To test the Phong shading, we can manipulate the viewing angle of the world as well as the orientation of the light. While the ability to manipulate the view matrix was previously completed, we added the ability to rotate the light orientation (a vector) about the X and Y axes using rotation matrices:

As a bonus implementation, we were given the challenge to implement point lighting with Phong shading: