Phong BSDF¶
Description¶
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¶
The spectral diffuse reflectance, or albedo, of the BSDF |
|
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 |
|
The surface flatness, between 0 (very rough) and infinity (very smooth) |
Parameters¶
name |
type |
description |
---|---|---|
ior |
real |
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
</spectrum>
</filtershader>
<filtershader name="specular" type="uniform">
<spectrum name="spectrum" type="rgb" rgb="1.0 1.0 1.0"/>
</filtershader>
<scalarshader name="exponent" type="uniform" value="3500"/>
</bsdf>