[vtkusers] Problems with vtkCamera::SetUserTransform()...

[Jannis Linxweiler]

Dear All,

I'm trying to change the perspective of a vtkCamera object using the
SetUserTransform method. I used the code from vtkCamera::Yaw() as an
example. 


CODE:
void MyYaw(double angle)
{
	//modify camera position
	vtkCamera *cam = this->ren1->GetActiveCamera();
	vtkTransform* transform = vtkTransform::New();
	vtkPerspectiveTransform* pTransform =
vtkPerspectiveTransform::New();
	double pos[3]; cam->GetPosition(pos);
	double newFocalPoint[3];
	double viewup[3]; cam->GetViewUp(viewup);

	//transform->Identity();
	// translate the camera to the origin,
	// rotate about axis,
	// translate back again
	transform->Translate(+pos[0],+pos[1],+pos[2]);   
	transform->RotateWXYZ(angle,viewup);
	transform->Translate(-pos[0],-pos[1],-pos[2]);
	
	cam->SetUserTransform(transform);
	transform->TransformPoint(cam->GetFocalPoint,newFocalPoint);
	cam->SetFocalPoint(newFocalPoint);
}

Unfortunately I'm not getting the same results as using the Yaw(angle)
method. Can anyone tell me what I'm doing wrong in this place?

If I change the code and use the line...

vtkTransform* transform = = cam->GetViewTransformObject();

instead of..

vtkTransform* transform = vtkTransform::New(); and
cam->SetUserTransform(transform);

...than everything works as expected.

Nevertheless this is not an solution for my Problem as it woks the same way
as Yaw() does. 

Thanks, Jannis