Changing the colour of something only when it overlaps with something

[AggrevatedCassawary]

I'm not sure how much sense the title makes, so I'll explain further:
I've got some black text that, at one point, goes over a black shape. Obviously, this means you can't read the part of the text that goes over that shape. I was wondering if there was a way to have only the part of the text that passes over the black part to change colour. So when my black text is overlapping with the black background, it turns white? I get the feeling you can do this with blending somehow, but any help would be appreciated!

 

[MrToM]

Can you just clarify....

Is this to work 'live' as in when either the text or shape move or...
Do you just want to fill a layer where the text and the shape overlap?

The latter is pretty simple, you can just make an exclusive selection.
The former is a little more tricky.

Regards.
MrTom.

 

[AggrevatedCassawary]

Can you just clarify....

Is this to work 'live' as in when either the text or shape move or...
Do you just want to fill a layer where the text and the shape overlap?

The latter is pretty simple, you can just make an exclusive selection.
The former is a little more tricky.

Regards.
MrTom.

Well I was thinking live, but that seems pretty unnecessary now that you mention it! In any case, thanks for (inadvertently) solving my problem.

 

[MrToM]

I'm sure somebody will have the right combination of blend modes and layer adjustments but black on black is tricky to blend.

Anyway, glad its sorted temporarily.

Regards.
MrTom.

 

[Zain Khan]

If its a text? You can select that portion of the text and simply colour it white, its that simple