Specular reflection is a reflection of light off a surface.  It produces highlights, which can be observed on any shiny surface.  Below, notice the white light reflecting off the apple.

Specular reflection depends on the viewer position.  When looking at an apple, If you move your head, you’ll notice the specular highlight moves as well.

In computer graphics, shininess is used to control the size of the highlight.  Shinier objects have smaller highlights.

A reflection of s about n produces the refection vector r.  In the Phong model, the specular reflection is determined from the angle between r and v.  This is also conveniently expressed as a dot product with normalised vectors.



A light’s specular component ls is reflected by a surface.  The amount of light reflection at each vertex is based on the reflection vector r, the viewing vector to the camera v,  and the surface specular material, ms.

The colour resulting from the specular reflection is:

where n is the shininess.



Some programmers only compute the specular term for points where s ·Ÿ n > 0.

High