In a continuation from yesterday's coverage of the Blinn-Phong lighting model I suppose I best add the next one [smile]

Cook-Torrance

This is a more advanced model that takes surface roughness into account. Consequently if we map roughness as a texture then we can have different areas of a surface appearing as smooth/rough. A classic example seems to be rusty metal - you have some shiny bits and then you have the rough/matt rusty parts.

The equation is somewhat less pleasant than before:



Inputs:

Diffuse Texture

Specular Texture

Normals Texture

Roughness Texture

Ambient Constant

Refractive Index Constant

Light Position Constant

Light Range Constant

Light Falloff Constant

World Matrix

World*View*Proj Matrix

Vertex Data:

Position

Normal

Tangent

TexCoord

With regards to creating a generic base for these lighting models it's worth noting:

We require an additional texture (Roughness)

We require a new constant (Refractive Index)

We no longer have the 'specular power' constant

All of the above fitting into yet another lovely Visio diagram (Visio rocks!):