Lighting refers to the handling of interactions between the light sources and the objects in the 3D scene. Lighting is one of the most important factor in producing a realistic scene.
The are two classes of lighting models:
1. Local illumination: consider only the direct lightings. The color of the surface depends on the reflectance properties of the surface and the direct lightings.
2. Global illumination: in real world, objects received indirect lighting reflected from other objects and the environment. The global illumination model consider indirect lightings reflected from other objects in the scene. Global illumination model is complex and compute intensive.