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[elijah]

Hi EveryOne,

I'm facing  a problem. I have an object ( gun ) in 3d space. When the user select another object , the gun must move to the direction of the object. I have look at some example  the PointAndClick test. It works when it does with the view. Can somebody give some code snippets. 

God Bless
Eng Huat

[Marvin Fröhlich]

It should be quite the same for a TransformGroup? What exactly is the problem?

Marvin

[elijah]

I got this code from the internet

Code:

// O is your object's position
// P is the position of the object to face
// U is the nominal "up" vector (typically Vector3.Y)
// Note: this does not work when O is straight below or straight above P
Matrix RotateToFace(Vector3 O, Vector3 P, Vector3 U)
{
  Vector3 D = (O - P);
  Vector3 Right = Vector3.Cross(U, D);
  Vector3.Normalize(ref Right, out Right);
  Vector3 Backwards = Vector3.Cross(Right, U);
  Vector3.Normalize(ref Backwards, out Backwards);
  Vector3 Up = Vector3.Cross(Backwards, Right);
  Matrix rot = new Matrix(Right.X, Right.Y, Right.Z, 0, Up.X, Up.Y, Up.Z, 0, Backwards.X, Backwards.Y, Backwards.Z, 0, 0, 0, 0, 1);
}

It does not work when O is straight below or straight above P. I must wondering is there any other better code around. I hear that
quaternion4f can do the job in a much simpler way and does not suffer from any short falls. But I'm lost in quaternion.

The example I follows from xith-tk, when I set the lookup(), the translation is being altered. I need the translation to be the same.

I hope this explains my problem in clear detail.

God Bless
Eng Huat

[Marvin Fröhlich]

Read the translation beforehand and apply it back after.

Marvin