Why? I've been trying to teach myself how to use Substance Designer in an effort to start texture modding and more specifically learn the PBR workflow.
List of definitions as I understand them:
- Diffuse maps - RGB map of the color of the texture.
- Specular maps - A map of how shiny a texture is. Can be greyscale or RGBA, but in OpenMW it's greyscale and stored in the diffuse map alpha channel.
- Normal maps - RGB map of angles, suitable only for small scale details because no height information is actually stored.
- Height maps - greyscale map of height information, can be used for large and small details. Same as bump maps and displacement maps (I've read conflicting info on these and they all seem to come down to the same thing).
- Parallax mapping - a shader technique that interprets height maps by faking depth within the mesh.
- Tessellation - a different shader technique that interprets height maps by actually adjusting the surface of the mesh.
I have several questions about all of this, so bear with me. I'd appreciate as much detail as possible and links to reading material is welcome as long as a relative beginner can understand most of it.
- Why do we use parallax mapping over tessellation? It seems like the added realism would be better.
- Is there an actual difference between tessellation height mapped detail and higher detail meshes besides the fact that height maps can be turned off at greater distances via LOD?
- Since height maps are greyscale, how is the range of values normalized in OpenMW? I.e. is there a value that modders should know about that will allow us to accurately view the height while designing the texture?
- Why do we combine height in with the normal maps in our texture rather than having them separate in a 3 channel file and a 1 channel file? Is the mere fact of having multiple maps open more resource intensive, because it seems like the actual size difference would be the same.
- In experimenting with Project Atlas, the batch files require all maps to be of the same type. Would there be a downfall to having a map with just normals also have an empty alpha channel, apart from slightly larger file size? Wouldn't the compression make this negligible for the un-atlased textures as it would all be one color and still be worth it for the atlased versions.
- Do we have any ambient occlusion maps? Or do we just bake that into the diffuse map?
- Do we have glow maps or any other kind of map available to us?
- Are there any .dds compression formats that OpenMW can't read?
- Are there any alternatives to .dds that are similar in performance?
- I know PBR rendering is very much a post-1.0 task, but if it's ever to become a thing, we'll have to figure out some way of transitioning. Remaking every. single. texture. is going to be quite the task, and people may not want to switch over anyway. Is there a way to allow both at the same time?