Create alpha from RGB texture

I’m working on a tesselated texture, and realized that I need to use the alpha channel of a texture to create the world displacement.

Is there any way to create an alpha channel from the RGB data of a texture? Like, could I use a grayscale image and somehow convert the brightness value of the pixels (0,255) to alpha (0,1)?


I think I’m on the right track here… I can use R,G or B channel with Linear Interpolate node. The results are a little unexpected, but I’m still experimenting and will post my results.