When it comes to creating frosted glass effects, many people think of the spiral blur node first, but in my opinion it is very outdated.
What I made now is a new blue noise blur function, Which uses significantly lower samples but provides much higher quality.
When it comes to low samples or high blur, the advantage of blue noise is more prominent.
It works by adding flicker noise to the scene color tex coord, so our trade-off is requiring a denoiser to work correctly.
I UNROLLed the loop in its custom code for profiling. I forgot that before uploading. You can remove that macro.
Get it here: