Game Development Reference
In-Depth Information
Figure 12.7
Radians allow you to readily measure angles.
radians. You start to the east. This direction corresponds to the positive direction
of the
x
axis.
East is usually considered the initial side of angles, so this is at degree 0. The
radian value of east is also 0. To now set the compass values for north, west, and
south, consider that if a complete revolution of a circle involves 2
radians, then
8
half a revolution (180
—west) involves
radians. If half a revolution involves
—north) involves
2
radians, then a quarter of a revolution (90
8
radians. When
you add
2
radians to
radians, you arrive at 3
2
radians. This is three-quarters of a
revolution or an angle of 270
8
—or south.
Table 12.1 provides you with radian and degree measurements for the angles that
represent the cardinal directions of the compass.
