rotate vector code example

Example 1: unity rotate vector

Vector3 rotated = Quaternion.AngleAxis(-45, Vector3.up) * vector;

Example 2: rotate 2d vector by angle

rotate vector (x1, y1) counterclockwise by the given angle
(angle in radians)

newX = oldX * cos(angle) - oldY * sin(angle)
newY = oldX * sin(angle) + oldY * cos(angle)