'''Originally Posted By: artbtjr''' Art Tucay Jr., Jason Hungerford<br><br>Directional light source: A directional light source is defined by a vector instead of a position. An example of this is the sun, where any distance within the scene is insignificant compared to the distance to the light source - so there is no need to compute a vector to the light source at each point. Instead, use a uniform vector.<br><br><br>Ambient lighting: Real life light bounces off every surface, lighting all objects in the vicinity. To substitute (approximate) this effect, the entire scene is added with an ambient color. Ambient lighting is constant color value added to the intensity of a scene.<br><br><br>Anisotropic material: Anisotropic materials will reflect different lights and shows different values depending on its rotation along a normal. It is passed a preferred tangent vector t.<br><br>Example: Brushed metal