Frosted glass texture?

For a shower door in a map I’m creating, I’d like to recreate the effect of frosted glass (as per usual for most
shower doors). I know how to create my own textures - the problem is, I have no idea how to start with this.
I assume it would need a shader, because frosted glass refracts what’s behind it, but I have no idea how to
implement a shader into a texture. I’m not too worried about the blurriness of color created by the glass, I’m
just looking for a way to apply the “frosted glass” look to a texture, be it by normal mapping or a shader.

This is what I’m going for, disregarding the blurriness of color beyond.

http://www.showerdoorcanada.com/photos/HG12.jpg

Refracting Textures

Ooh, that’s helpful. I’ll follow the instructions and provide a screenshot if I get it to work.