I only found an option to "add normal roughness to alpha channel" from another normal texture. But that's not really what I need.
I am putting together some landscape textures and (since samplers are limited in number) I want to use the alpha channels of diffuse and normal map for roughness and specularity. Since these are both grayscale, it seems like the best solution. But can I "compose" textures like this inUE4 or do I have to do it externally?
asked Jul 31 '16 at 09:48 PM in Rendering
Most likely you will have to do it externally.
Be advised, however, that storing alpha channel virtually doubles memory usage of your texture, and using additional channels in normal maps provides a bunch of complications. There are some discussions on the forum about that:
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