driving opacity based on another layer’s pixel value?
I was wondering if there was a way to drive the opacity of one layer by a/the value of a pixel or a group of pixels on another layer.
Basically, I’ve got a grayscale image of a light(really just the color white in the center of, but not taking up, the frame) on “layer 1” flashing on and off. I want the intensity value of one of that image’s pixels (or, say, an average of a group of the pixels that make up this flashing “light”) to drive the opacity of another layer (“layer 2”).
Does this make sense? Is it possible?
Julius Caesar and the Roman Empire couldn’t conquer the blue sky.