Game Development Reference
In-Depth Information
Point Light
A point light is a light placed at a specific point that emanates in all directions.
Because they emit from a specific point, point lights also will illuminate only one
side of an object. In most cases we don't want the point light to travel infinitely
in all directions. For example, think of a light bulb in a dark room, as shown in
Figure 4.13(a) . There is visible light in the area immediately around the light, but
it slowly falls off until there is no longer any more light. It doesn't simply go on
forever. In order to simulate this, we can add a falloff radius that determines how
much the light decreases as the distance from the light increases.
Figure 4.13 A light bulb in a dark room is an example of a point light (a). A
spotlight on stage is an example of a spotlight (b).
Spotlight
A spotlight is much like a point light, except instead of travelling in all directions,
it is focused in a cone. To facilitate the cone, it is necessary to have an angle as
a parameter of spotlights. As with point lights, spotlights will also illuminate one
sideofanobject. Aclassic example ofaspotlight isatheater spotlight, butanother
example would be a flashlight in the dark. This is shown in Figure 4.13(b) .
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