Quick follow up question if anyone here has the time to answer: Is it true that, at least on the GPU side, a “Context Switch” caused by a Drawcall is actually cheaper when little changes, for example the same material with different texture inputs is used (for example a material instance), versus a “Context Switch” to a completly different material using a different shading model, blend mode, and whatnot?
This would mean modern GPUs are already optimized to recognize when the same input is used and circumvent loading the same data again, correct?
Now that Drawcalls shouldn’t be the huge bottleneck to the CPU anymore with DX12 and Vulkan, this might become more important… would mean that you can split your models into multiple materials fine with little overhead (unless there is a batchsize limit to drawcall batching in DX12 or Vulkan), as long as the materials are as similar as possible.
Reason for the question is that all this discussion of splitting the mesh into more UV maps to use multiple materials has gotten me thinking that I might want to split the “main part” of the mesh into 2 UV maps, because that part at the moment would be best to use a 1024x2048 Texture, yet I read that using nonsquare maps in Unreal engine 4 would be a bad idea. 1kx1k has to low resolution, 2kx2k has too high, and having two 1kx1k ones would give me enough resolution without needing more VRAM than really needed.
Thus if I can use 2 material instances without a big hit under modern rendering pipelines, that is probably what I will end up doing. At least for the highest LOD…