Thanks for all the replies…
So then I simply cannot see the impact in stats because a) stats only show the raw tris, without adjusting for double sided (which makes sense), and b) the render time does not budge because the additional load will probably not show up until a bottleneck is reached with an increasing instance count of the same character being visible, which might happen sooner thanks to the double sided material, correct?
I am trying to save on render cost here as I might want to have many characters onscreen, and therefore I wanted to make sure the material is as cheap as possible. Also, the characters will not be seen up close, so I thought about simply not caring about hair and skin shader, and use a simpler subsurface material, which, with well created maps, has usually been good enough when seen from a certain distance. I thought that fitting everything into a single material would be best for DX9 and DX11 performance, don’t know how relevant draw calls still are under DX12 / Vulkan (haven’t had time to really look into this).
But then I have been using Unity for a long time, where saving on draw calls is extremly important because the engine has almost no “automagic” to do that for you (save for static meshes)…
So given you don’t need specialized shading models for different parts, and COULD fit everything into one material. Do you reckon its a good idea to try to go with the least amount of materials you can go away with? Is reducing the amount of materials from 2 to 1 worth about 3-4000 additional tris being double sided, even if they don’t have to be?
Or is it not really that much overhead for the GPU if the character is split into 2 materials, compared to the additional tris being rendered double sided?
Looking at the shader cost view mode, that looks identical to the shader without double sided… green-ish (yeah, the accuray of that is probably not too great given you need to eyeball it). I guess this only takes the 4 additional base pass instructions into account, but not what they are spent on? Only the cutout parts (which thankfully are small) appear red, due to overdraw I guess.
This view mode makes me believe that the double sided tris are cheaper than the area that is affected by the opacity mask… is that true? Or just the view mode not taking everything into account?