Computer graphics lighting  Computer graphics lighting is the collection of techniques used to simulate light in computer graphics scenes. While lighting techniques offer flexibility in the level of detail and functionality available, they also operate at different levels of computational demand and complexity. Graphics artists can choose from a variety of light sources, models, shading techniques, and effects to suit the needs of each application. Light sources allow for different ways to introduce light into graphics scenes. Point sources emit light from a single point in all directions, with the intensity of the light decreasing with distance. An example of a point source is a standalone light bulb. A directional source (or distant source) uniformly lights a scene from one direction. Unlike a point source, the intensity of light produced by a directional source does not change with distance, as the directional source is treated as though it is extremely far away from the scene. An example of a directional source is sunlight. A spotlight produces a directed cone of light. The light becomes more intense closer to the spotlight source and to the center of the light cone. An example of a spotlight is a flashlight. Ambient light sources illuminate objects even when no other light source is present. The intensity of ambient light is independent of direction, distance, and other objects, meaning the effect is completely uniform throughout the scene. This source ensures that objects are visible even in complete darkness. In computer graphics, light usually consists of multiple components. The overall effect of a light source on an object is determined by the combination of the object's interactions with these components. The three primary lighting components (and subsequent interaction types) are diffuse, ambient, and specular. Diffuse lighting (or diffuse reflection) is the direct illumination of an object by an even amount of light interacting with a light-scattering surface. After light strikes an object, it is reflected as a function of the surface properties of the object as well as the angle of incoming light. This interaction is the primary contributor to the object's brightness and forms the basis for its color. As ambient light is directionless, it interacts uniformly across all surfaces, with its intensity determined by the strength of the ambient light sources and the properties of objects' surface materials, namely their ambient reflection coefficients. The specular lighting component gives objects shine and highlights. This is distinct from mirror effects because other objects in the environment are not visible in these reflections. Instead, specular lighting creates bright spots on objects based on the intensity of the specular lighting component and the specular reflection coefficient of the surface. Lighting models are used to replicate lighting effects in rendered environments where light is approximated based on the physics of light.