Cook-Torrance BRDFs are the foundation of current physically based shading systems. I wrote my own version of a Cook-Torrance based off Siggraph papers published by Disney and Epic. Physically based shading takes into account microsurface roughness and obeys basic laws of reciprocity. This makes the shading algorithm look more ‘real’ compared to Blinn or Phong shading. Cook-Torrance shaders are however several magnitudes more complex than Blinn/Phong.