10.1.4 Phong Shading by Adaptive Tessellation

Phong highlights can also be approached with a modeling technique. The surface can be adaptively tessellated until the difference between $(\vec{H} \cdot \vec{N})^n$terms on triangle vertices drops below a predetermined value. The advantage of this technique is that it can be done as a separate pre-processing step. The disadvantage is that it increases the complexity of the modeled object. This can be costly if:

• The model will have to be clipped by a large number of user-defined clipping planes.
• The model will have tiled textures applied to it.
• The performance of the application/system is already triangle limited.