Initializes this to represent a rotation of x_angle degrees around the x axis, then
y_angle degrees around the y_axis and z_angle degrees around the z axis.
| this |
The Euler angle to initialize |
| heading |
Angle to rotate around an object's y axis |
| pitch |
Angle to rotate around an object's x axis |
| roll |
Angle to rotate around an object's z axis |