[vtk-developers] renderer-based camera light tracking checked in

[Lorensen, William E (CRD)]

A followup to the previous message:

Here's what I think has happened. cut.tcl is a representative example of a script that is "failing"
with the new camera/light logic.

In the past, the first render creates a light and camera if they are not specified. Then, a
subsequent change to the camera followed by a render, leaves the generated light where it was on the
first render. This is probably not good behaviour, because the light is not "following" the camera.

Now, I believe, the light correctly follows the camera. I think we should look at each failing
script, validate the results we see as possibly correct and either:

1) Change the baseline image
2) Modify the script to use a different kind of light.

Bill
 
-----Original Message-----
From: Michael Halle [mailto:halazar at media.mit.edu]
Sent: Wednesday, August 23, 2000 12:15 PM
To: vtk-developers at public.kitware.com
Subject: [vtk-developers] renderer-based camera light tracking checked
in



Hey,

I checked in the changes to add improved light/camera tracking to
vtkRenderer.  

I believe the changes to be backward compatible, since I didn't change
any of the code in the interactors.  So, to use the improved tracking,
new code should turn OFF the interactor's LightFollowCamera flag and
let the renderer handle the tracking.  The Tk interactors in
examplesTcl don't have a way to turn off tracking, so the first light
instanced will always be a headlight (but will be rendered incorrectly
only if the user specified it as a CameraLight, which won't happen in
legacy code).

I also haven't hacked any rendering code outside of vtk*Renderer to
use vtkLight::GetTransformedPosition() and FocalPoint(), so code
that used GetPosition() and GetFocalPoint() won't work correctly
with lights that are CameraLights (Headlights and SceneLights work).
Since a change in lighting behavior could possibly botch all the
regession tests, I don't want to wack too much at once :)

I also added a new test, CameraLights.tcl / CameraLights.py, that 
demonstrates the new functionality.


							--Mike


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