Basics of Scene Construction - 3D Game Development Practical Introduction - page 20

The main difference between Scene and Game views is that the latter does not allow you to
surf freely in the scene and limits you to the view of the main camera, from which the player
observes the game world. If you select the Main Camera game object from the hierarchy, you
will see a number of properties including:

1. Background : the color that fills the horizon of the scene. Empty areas that are
not covered by any visible game objects are going to appear in this color.
2. Projection : determines whether the distance between an object and the camera af-
fects the size of that object when rendering it. In the default Perspective projection, far
objects are rendered smaller than near ones. This behavior is similar to human vision
system. In the Orthographic projection, all objects are rendered with their original
size, regardless of how near or far they are from the camera. Orthographic projection
is useful in some cases, like 2D games.
3. Field of View

4. Clipping Planes (Far and Near)

Field of view option is only available in the perspective projection. In this projection, the fi ld
of view takes a shape of a frustum. If you complete this frustum to a pyramid, the head of the
pyramid is at the position of the camera, and the base of the pyramid is the far clipping plane.
The near clipping plane is what turns the pyramid into a frustum, while the fi ld of view is the
angle between left and right sides of the frustum. Illustration 11 shows how does the camera
use the view frustum to determine the visible objects in the scene. Illustration 12 shows the
same scene from the perspective of the camera, and the player as well.