Write GLSL shaders to implement: (a) per-vertex; and (b) per-pixel shading. Incorporate
the shaders into a Processing program that creates a scene with a 3D object and includes
a point light. Modify your shaders so that they use the Phong illumination model; namely,
modelling specular, diffuse and ambient light components. Make these components
adjustable by the user and show how each one of them affects the result. Compare and
contrast the two shading methods and comment on their effect.