These are the common light sources. Point light radiates light outwards in all directions from a single point, much like a candle or a bulb; by the way stars in our space are point lights too. A directional light source emits light in one direction ...it could be for instance a large LCD screen. Sun is on Earth surface also considered as directional light source (because we are relatively much near to Sun). Spotlight emits a light beam which usually has highest intensity in its center. A flashlight (torch) is a typical source of spotlight. I painted these pictures for my brother's publication about OpenGL.
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