Texturing from a scene

I want to make a moving texture. I know that I could do it by rendering a movie, and then using the movie as the texture. I just wonder whether it would be possible to use output from a camera in a different scene (within the same .blend file) directly, rather than having to first render it to a movie? I plan to make frequent changes to the moving part, and it would be convenient if I didn’t have to re-render the whole movie with each change.

Perhaps Environment Maps would be useful: http://mediawiki.blender.org/index.php/Manual/PartIV/Environment_Maps

Thanks. That might do the trick. The thing is, I want the object to respond to changes in a layer/scene which is not visible to the camera. So if I can create an environment map for an unseen object, in an unseen environment, then apply that environment map to the relevant object in my scene, then I’m sorted. I’ll see if it can be done…