HALF_PI

A Number constant that's approximately 1.5708.

HALF_PI is half the value of the mathematical constant π. It's useful for many tasks that involve rotation and oscillation. For example, calling rotate(HALF_PI) rotates the coordinate system HALF_PI radians, which is a quarter turn (90˚).

Note: TWO_PI radians equals 360˚, PI radians equals 180˚, HALF_PI radians equals 90˚, and QUARTER_PI radians equals 45˚.