Steps to Reproduce
Hi there!
After upgrading our UE4.27 project to 5.3, it was found that the draw-call ordering for some of our meshes in the Opaque pass had changed!
Unfortunately now the Sky-material+mesh now renders before the fore-ground floor material+mesh.
Because of that the expensive sky pixel shaders are now working alot harder since more pixels now pass the depth test with this new draw call ordering seen. In UE5 that results in rendering the sky before the floor.
What determines the Draw call ordering In UE5? Specifically for the opaque pass in this situation, but also interested about the transparent pass.
I would like to dig into more why this ordering has changed for the worse for us here.
FMeshDrawCommandSortKey sounds like it might have something to do with it?
If some-one could point me to the area of the engine code in the forward desktop and mobile forward renderer in UE5.3 that would be a great help.
Additionally, any suggestions of how to affect the sorting order?
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Many thanks