These functions will let you convert rotations into a vector (axis) and the angle the vector is rotated by (the rotation is perpendicular to the vector). The final function lets you convert back.
vector getVecFromRot(rotation r)
{//llRot2Axis
vector v = <r.x, r.y, r.z>;
if(v)//Is the vector a zero vector?
return llVecNorm(v);//not a zero vector, so normalize it
return v;//vector was zero.
}
float getAngleFromRot(rotation r)
{//llRot2Angle
return 2 * llAcos(r.s / llSqrt(r.x * r.x + r.y * r.y + r.z * r.z + r.s * r.s));
}
rotation getRotFromVecAngle(vector v, float a)
{//llAxisAngle2Rot, not normalized
return <v.x, v.y, v.z, 1 / llTan(a / 2)>;
}