rotate_x_to

vector2  rotate_x_to(vector2 direction, vector2 v)

vector  rotate_x_to(vector direction, vector v)

vector4  rotate_x_to(vector4 direction, vector4 v)

direction

Direction to which a vector along the positive x-axis, e.g. (1,0,0), would be rotated. This does not need to be normalized.

v

Vector to which to apply the rotation.

Applies to v, the rotation that would move (1,0), (1,0,0), or (1,0,0,0) to direction most directly.

In the case of direction being (-1,0,0), there are multiple distinct rotations that would move (1,0,0) to (-1,0,0) with a half turn rotation, so one is chosen arbitrarily, negating v.x and v.z. In 2D, there is only one distinct rotation that moves (1,0) to (-1,0), equivalent to negating v. In 4D, the rotation where v is negated is also chosen.

This is used by functions like sample_direction_cone and sample_sphere_cone to rotate the cone centre from (1,0,0) to a given direction vector.