Observe: I intend to make use of solely the Inspector window to make use of all textures, not Shader Graph or Nodes or any customized scripts. Additionally I’d use some technical phrases incorrectly by mistake, as I am not a lot skilled in it, however I might strive my finest to elucidate points.
I’ve discovered that URP would not have a devoted choice in Inspector to enter a Smoothness map (like base, peak, regular maps and so forth.).
However there’s a resolution for it – utilizing channel-packing. That is the one data I discovered in Unity docs however sadly it is not sufficient the way to do it:
Within the Lit and Complicated Lit shaders within the Common Render Pipeline (URP), you should use a single RGBA texture for the metallic, smoothness, and occlusion properties. This method known as channel packing or texture packing.
Assign the feel to the Metallic and Occlusion properties of the fabric. Unity robotically makes use of the right channels from the feel.
So mainly you want smoothness greyscale picture for alpha channel of RGBA texture.
Now, there’s not a lot clear details about the way to correctly create it and what format to export in. Perhaps it is simpler to do in Photoshop however I solely use Affinity Photograph and GIMP.
I watched many tutorials, and most of them appear to export the channel-packed texture as PNG picture. However on numerous forumns, I came upon that PNG format has subject when "storing" greyscale texture in alpha channel, while you do it with some picture modifying apps like Affinity Photograph or GIMP. It messes up with RGB channels the place there may be pure black in alpha channel. Additionally, clearly, the ultimate PNG appears to some areas of transparency due to alpha.
This reply additionally appear to counsel PNG won’t work when utilizing Photoshop. Additionally, there are two solutions associated to GIMP too, however they did not appear to unravel subject once I exported them in PNG. One among them (compose-decompose associated) had identical drawback of shedding RGB particulars wherever there was full black in alpha channel. Once more, it exported a picture with some transparecy. The opposite reply I could not actually use for my wants. It was not clear to me. They do not specify any particular export format. They doubtless intend to make use of solely PNG.
Which leads me to ask: Is this sort of channel-packing with transparency would work as supposed in URP shader for metallic, smoothness and occlusion?
I additional discovered on a Reddit put up that you just do not truly use PNG format for this sort of channel packing. You utilize TGA format as that "correctly" shops alpha channel.
Seeing this combined data, it made me solely confused. I am unsure the way to proceed.
I could not actually discover any good supply the place alpha channel packing and picture codecs are mentioned for GIMP and Affinity Photograph. Affinity appears worst for this objective.
Given all that, is it truly doable to export it appropriately and use it in PNG format (particularly in GIMP)? Or I need to use one other format like TGA?
