Liquids, skies and fullbright pixels should have emissive materials

[andyp123]

Some textures should be entirely emissive, and others need an emission mask generating and shader setting up. There is some code to create the mask, but it creates an upside down mask, and the mask needs to be assigned in a shader so the emissive material works properly in the viewport.

[andyp123]

This works properly now