I have a plane rotated by the defined rotator R1. There is a vector V laid in this plane. I want to rotate this vector by, lets say, 30 deg. clockwise, BUT IN THIS PLANE (i.e. rotate about this plane normal). Lets name this second rotator (0, 30, 0) R2.
I know, I can get wanted result by:
Variant 1: rotate V back by inversed R1, then rotate result by R2, and rotate this last result vector by R1.
Variant 2: build quaternion (by normal to the plane & known angle (30 deg.))
But may be there is some faster variant (with easier calculations or just less code) which lets “rotate a rotator”. I.e. to rotate R2 by R1 to get simply 1 result rotator R3, to rotate V by it & get same result as by two other variants?
the vector only exists on your plane and thus it’s actually a 2d problem. (plane == 2 dimensions). what you have to do is projecting the vector in global coordinates to the coordinate system of the plane, rotate it there and unproject it back to the global.