[Bug] prevent unexpected error in renderPassAll if polyData mapper does not exist

[sedghi]

Bug description

This is not a bug, but rather an unexpected error.

When there is no polyDataMapper, the renderPassAll goes through polyDataMapper. Since it doesn't have any input, it will throw an error. I'm not sure why it should through an error. Can I create a PR to fix this issue?

Steps to reproduce

I have not tried vtk.js examples, but this is happening in Cornerstone3D.

Detailed Behavior

No response

Expected Behavior

To not through, and only return

Environment

• vtk.js version: 29.3.0
• Browsers: Chrome
• OS: macOS

[finetjul]

I think the error is here to give a clue to the developer why the rendering is pitch black.
It is questionable why you have a polydatamapper without polydata. Alternatively you could turn off the visibility of the actor to prevent the error.
It could be a warning and not an error though.