2D fullscreen blur based on gradient? Is it possible?

I have a project in 3d and I’m looking to add a post effect that blurs the edges of the screen in the same way the vignette darkens the edges of the screen. I don’t want it to have anything to do with depth so simple DoF isn’t working to accomplish my goals. Is there any way to blur a texture so I can do it with a material post effect? Or is there another way to force portions of the screen to be blurred on top of the DoF blur?

Hate to be the bearer of bad news, and after so long, but I’m afraid it’s impossible. This engine has a ton of limitations, you have to either work around them or accept them.

An example of working around them would be to make a render target out of the final result (with mip settings being blur5), then sample the mip higher towards the edge. It’s not perfect, but it looks convincing as long as you don’t look at the edges too much (as there might be clear signs of lower resolution).