public Vec3 RotateAround(Vec3 axis, float angle)
{
// rotate into world space
var quaternion = Quat.FromRotationAxis(axis, 0);
quaternion = quaternion.Conjugate();
var worldSpaceVector = this.Transform(quaternion);
// rotate back to vector space
quaternion = Quat.FromRotationAxis(axis, angle);
worldSpaceVector = worldSpaceVector.Transform(quaternion);
return(worldSpaceVector);
}
public Mat3 RotateAround(Vec3 axis, float angle)
{
// rotate into world space
var quaternion = Quat.FromRotationAxis(axis, 0).Conjugate();
var worldSpaceMatrix = this.Multiply(FromQuaternion(quaternion));
// rotate back to matrix space
quaternion = Quat.FromRotationAxis(axis, angle);
var qMat = Mat3.FromQuaternion(quaternion);
worldSpaceMatrix = worldSpaceMatrix.Multiply(qMat);
return(worldSpaceMatrix);
}
public Mat4 FromRotationAxis(Vec3 axis, float angle)
{
Quat quaternion = Quat.FromRotationAxis(axis, angle);
return(Mat4.FromQuaternion(quaternion));
}