Phong reflection/shading

[doofus]

I know I'm probably being very thick but can someone tell me the difference between implementing the phong reflection and phong shading models??

Cheers,

[dorbie]

I wish you'd asked the difference between phong lighting and phong shading (or something similar).

Phong lighting is a lighting equation where you have diffuse as L.N and specular as V.R (raised to the power of the specular exponent value) where L is the light vector, R is the reflected light vector, N is the normal and V is the view vector (all normalized).

Phong shading is basically per pixel lighting where the normal is interpolated from per vertex normals before the per pixel lighting calculation.

These days most people use Blinn's "Half" angle instead of the reflected light vector in the specular equation, the half angle being half way between the view vector and the light vector.

So exactly what phong reflection means in your context is unclear. Someone may be drawing a distinction about the use of the reflection vector vs the half vector for the specular equation.

[ce110ut]

offtopic: great response - it took me a while to get the hang of it but with your "breakdown" of phong lighting, i understand now.

thanks.

-=[ regards ]=-