Unfortunately, by the nature of the technology, cracked glass likely means your digitizer is out of commission (does touch still register on the cracked screen?). Below that is the LCD, and that might not be broken (if the image is fine, then the LCD is likely fine). The problem is that these components are VERY VERY difficult to separate. This makes the individual replacements a nightmare. I hate to say anything is impossible, but separating these components will feel impossible without expensive tools and extensive knowledge. It will also likely end in a mess of broken components. When there is a will, there is a way. But the separation project will demand a lot of will.