Overlay scene question.

I’ve done “bars” (HP, MP, EXP, ext…) with overlay scenes before, but they were all one blank color, and to have them go up and down, I just made an animation and set the frame to a variable.
But this time, I’m using a texture on the bar, and I don’t want it to ‘squish’. (see image)
“So what”, one may say, “just make a black bar that goes the opposite direction, and covers it up”! Well for various reasons in relation with what I want to achieve, I can’t use this method.

So my question is - ‘Is there some way of making part of an object see-through, during run-time?’ Like, a ‘mask’ or something?

Use global coordinates for the textures, this way texture is not affected by the object changes?

Alternatively, alter the UV values of the texture as you adjust the scale manually.

In similar case I used “generated” coordinates with a shape key animation and it worked fine

I’ll try some of these tomorrow morning. (it’s 11:08 where I am).