[vtkusers] Disable lighting for an actor

[Thomas Demachy]

Hello !

Using OpenGL rendering, I wish to disable lighting / shading on my actors,
so the color information used is exact and not modified by the shading. In
OpenGL, the used keyphrase is : glDisable (GL_LIGHTING).

The book says "If enabled, use the current lighting parameters to compute
the vertex color or index. If disabled, associate the current color or index
with each vertex."

It is indeed used several times in the class vtkOpenGLPolyDataMapper, for
intance when rendering vertex without normals. But there seems to be no
property member nor rendering method to disable lighting.

The best solution would be to add a "Lighting" property to vtkProperty, just
like "BackfaceCulling", so we can fine-tune this parameter for each actor.
The Mapper will then adjust itself to this parameter.

Does anybody have the same needs ? Or is there a better solution ?

Thomas