Phong BSDF



Example of phong BSDF

BSDF This BSDF type follows the Blinn-Phong reflection model.

It corresponds to densely diffuse materials, with a surface smooth enough to allow specular reflection, such as smooth paints, laquered or varnished surfaces.

This is a more refined model than Lambertian BSDF for describing diffuse surfaces. As opposed to Oren-Nayar BSDF, the Blinn-Phong model was derived more empirically than by using a real physical model, and describes more a shading algorithm for real-time graphic than a physical phenomenon. The actual equations used in Ocean were adapted to fit a physical approach.

Children Nodes

Filter shader diffuse

The spectral diffuse reflectance, or albedo, of the BSDF

Filter shader specular

The spectral reflectance of the specular component of the BSDF. This is modulated by the fresnel coefficient, which depends on ior parameter. The default value is 1

Scalar shader exponent

The surface flatness, between 0 (very rough) and infinity (very smooth)







The refractive index of the surface

Ocean XML 4.0 example

<bsdf name="bsdf" type="phong">
   <prm ior="1.5"/>
   <filtershader name="diffuse" type="uniform">
      <spectrum name="spectrum" type="tabulated" start="380E-9" end="780E-9" num="8">
         0.2 0.25 0.3 0.35 0.5 0.6 0.7 0.7
   <filtershader name="specular" type="uniform">
      <spectrum name="spectrum" type="rgb" rgb="1.0 1.0 1.0"/>
   <scalarshader name="exponent" type="uniform" value="3500"/>