New vtkCamera class

[David Gobbi]

Hi all,

I've made some changes to vtkCamera that will impact
backwards-compatibility.  The changes will be added to CVS
tonight, and will appear in the nightly builds on Thursday.


Item 1:  SetViewPlaneNormal(),  ComputeViewPlaneNormal()

Both of these methods are deprecated, and will print a warning
if you use them.  The ViewPlaneNormal is always automatically
calculated now, and GetViewPlaneNormal() works as before.


Item 2:  SetDirectionOfProjection(), GetDirectionOfProjection()

These are new methods.  The DirectionOfProjection is the vector
from the camera to the focal point, normalized to a length of 1.
Unlike the old SetViewPlaneNormal method, the SetDirectionOfProjection
will move the focal point to match the new direction of projection.
If you want to determine whether a surface normal is pointing
towards or away from the screen, you should still use
GetViewPlaneNormal() as before.


Item 3:  SetObliqueAngles(alpha,phi)

Most people will never use this... this new method allows you to
specify the orientation of the ViewPlaneNormal relative to the 
DirectionOfProjection.  It results in a shear distortion of the
projection matrix.


Item 4:  GetViewTransform()

Get the view transform for the camera.  This transform is always
up-to-date with respect to the camera Ivars.  There is no
SetViewTransform() method, but one could be added in the future.


Item 5:  GetOrientation()

This method used to return double *, now it returns float *.
The reason for this change was code simplification. 


Rationale:

The primary reason for these changes are that I was tired
of getting weird, distorted camera views when I set the 
ViewPlaneNormal incorrectly.  The rest of the changes reflect
a clean-up of the source code.

 - David


--
  David Gobbi, MSc                    dgobbi at irus.rri.on.ca
  Advanced Imaging Research Group
  Robarts Research Institute, University of Western Ontario

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