Right, it's been almost 2 weeks since I last posted a lighting model. It's almost criminal how busy I've been lately [headshake]

On the plus-side for you guys I've greatly improved the HDR Demo sample that I wrote. Look out for that in a future SDK. [wink].

In an addendum to the Oren-Nayar entry... courtesy of a PM from rollo I've realised that there the Sin()Tan() map is actually going to be essential for a ps_2_0 version. From preliminary research, the pure mathematical expansion of that term will vastly exceed the limits of a ps_2_0 profile [lol]

Ward Reflection Model

The Ward reflection model (published in the SIGGRAPH 1992 proceedings) is one of the better models for simulating metalic surfaces. It varies the specular component based on the "direction" of the surface... thus being able to mimmick brushed metallic surfaces (amongst other things)...



Inputs:

Diffuse Texture

Normal-map Texture

Specular-map Texture

?X?Y Coefficients Texture

Ambient Constant

Light Position

Light Range

Light Falloff

World Matrix

World * View * Proj Matrix

Vertex Data:

Position

Normal

Tangent

TexCoord

And, as usual, a pretty Visio diagram: