Jump to content
  • Advertisement


This topic is now archived and is closed to further replies.


Rotate around point ala Cinema4D problem!

This topic is 5397 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

Hi! I have a small problem! I am building a camera control that should work like the one in Cinema4D. It should be able to rotate around the selected object in the scene. The rotation around the selected object works just fine. But when I am selecting a different object the camera "jumps" to a another position. I want the camera to stand still just change the circle the the camera should rotate around. Here is some code
private Quaternion m_qX;
private Quaternion m_qY
private matrix m_rotation;
private matrix m_view;
private Vector3 m_rotationPoint;
private Vector3 m_camPosition;

public void RotateAxisWithAngle(Vector3 axis, float angle)
  float cosA = (float)Math.Cos(angle/2.0f);
  float sinA = (float)Math.Sin(-angle/2.0f);
  m_qX *= new Quaternion(axis.X*sinA, 0, cosA)
  m_qY *= new Quaternion(0, axis.Y*sinA, cosA)
  Quaternion q = m_qY * m_qX;
  m_rotation = matrix.RotationQuaternion(q)
public void RecalculateViewMatrix()
  m_view = Matrix.Translate(-m_rotationPoint.X, -m_rotationPoint.Y, -m_rotationPoint.Z);
  m_view *= m_rotation;
  m_view *= Matrix.Translate(m_rotationPoint);
  m_view *= Matrix.Translate(-m_camPosition.X, -m_camPosition.Y, -m_camPosition.Z);
ok its in the RecalculateViewMatrix() code where the problem lies. It make the camera "jump" when i change the rotationPoint. Is there any simple solution to this? I have tried all kinds of matrix multiplications. ((P)^-1*R*P*T, ....) but nothing worked! Thanks! Magnus Stålberg

Share this post

Link to post
Share on other sites

  • Advertisement

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

Participate in the game development conversation and more when you create an account on GameDev.net!

Sign me up!