When supplied with a normal map this can be used to create cracked glass, frost, scratches, water drops etc.
Several example maps are included in the samples package
- Clear ice
- Cracked glass
- Water drops
If you’d like to use your own refraction map, you can convert a normal map to a DUDV map, which is similar to a normal map, but doesn’t have a blue channel. More information can be found here: http://wiki.polycount.com/wiki/DuDv_map. Alternatively, you can use a normal map and check the
Using normal map checkbox to perform the conversion in the shader.