Real-Time 3D Graphics with WebGL 2 - Second Edition

The Lambertian Reflection Model

Lambertian reflections are commonly used in computer graphics as a model for diffuse reflections, which are the kinds of reflections where an incident light ray is reflected in many angles instead of just one angle, as is the case for specular reflections:

This lighting model is based on the cosine emission law, or Lambert's emission law. It is named after Johann Heinrich Lambert, from his Photometria, published in 1760.

The Lambertian reflection is usually calculated as the dot product between the surface normal (vertex or fragment normal, depending on the interpolation method used) and the negative of the ...