Game Development Reference
In-Depth Information
Directional light is the most widely used light source in games because it is one of
the easiest to calculate. It is also a light that you are comfortable with because you
see it every day in real life. Directional light can be general, as in Figure 1.15, or it
can be limited, like a spotlight. Limited directional lights are called spotlights or
conical lights .
Ambient Light
An ambient light is a general light source that lights all surfaces in all directions. It
is usually combined with a point or directional light to give a scene a more natural
appearance. Ambient light is the result of light bouncing off one surface and then
another. Most light in a home that comes through the windows is ambient light
even when the sun is shining directly through the window. Because the nature of
light is to bounce from one surface to another, shadows are not completely black.
You might have noticed that the shadows in Figures 1.14 and 1.15 are almost com-
pletely black, which gives them a very unnatural look. In real life, light bounces off
everything so almost all shadows have some light. Look at Figure 1.16, and notice
that the shadows are much softer and the ball looks three-dimensional. The ambi-
ent light simulates the reflected light normally seen in real life.
Almost every scene needs to have some ambient light to make it look realistic. The
only exception is a game set in deep space, where there is little or no reflected light.
Figure 1.16 An ambient light is used to light the shadow areas.
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