#include C3D_FQuat Quat_RotateY(C3D_FQuat q, float r, bool bRightSide) { float c = cosf(r/2.0f); float s = sinf(r/2.0f); if (bRightSide) return Quat_New(q.i*c + q.k*s, q.r*s + q.j*c, q.k*c - q.i*s, q.r*c - q.j*s); else return Quat_New(q.i*c - q.k*s, q.r*s + q.j*c, q.k*c + q.i*s, q.r*c - q.j*s); }