Task: Text Categorization
Input (English): One type of this can be approximated with a model that incorporates hardness and which is similar to the Oren-Nayer model, the Blinn model. The Cook-Torrance model involves terms for surface roughness and geometric attenuation and implements a four dimensional model for it, the BRDF. Another model of this process employs a namesake interpolation and combines the constants ks, kd, and ka and is known as the Phong model. The Lambertian model for this does not change based on the position of the viewer and is used in modeling the diffuse form of this, the opposite of the specular type of it. The angle of this is equal to the angle of incidence, while at angles larger than the critical angle, the total internal type of this occurs. FTP, identify this phenomenon commonly produced by lakes and mirrors.
Output (English): Science