#Static Batching vs Mesh.CombineMesh
thin atlas
Static batching combines the meshes into the same vertex and index buffers, and when it submits the draw calls to the GPU, it can do:
SetMaterial(material)
SetVertexBuffer(combinedVertices)
SetIndexBuffer(combinedIndices)
DrawIndexed(mesh1_offset, mesh1_count)
DrawIndexed(mesh2_offset, mesh2_count)
etc...
Instead of if the meshes aren't combined:
SetMaterial(material)
SetVertexBuffer(mesh1_vertices)
SetIndexBuffer(mesh1_indices)
DrawIndexed(0, mesh1_indices.count)
SetVertexBuffer(mesh2_vertices)
SetIndexBuffer(mesh2_indices)
DrawIndexed(0, mesh2_indices.count)
etc...
So it minimizes the render state changes by reducing how often it's switching between meshes, like the documentation says:
Static batching doesn’t reduce the number of draw calls, but instead reduces the number of render state changes between them.
Static Batching vs Mesh.CombineMesh
But it's effectively the same as combining it into the same draw call, because the draw calls themselves aren't the most expensive part, but preparing the state before them.
SRP Batcher works on the same principle. It doesn't reduce draw calls, but makes them cheaper
https://docs.unity3d.com/Manual/SRPBatcher.html
The traditional way to optimize draw calls is to reduce the number of them. Instead, the SRP Batcher reduces render-state changes between draw calls.
vital fable
I though you could make 1 single draw call by batching every index in one array. Maybe it is only specific to some GPU API.
It might be the same at the end too.
lethal parcel
Ehh the game is definitely mostly cpu bound just because the stock code is pretty awful. Also fwiw I’m measuring draw calls with renderdoc, so maybe there’s some details there that you don’t see in the unity frame capture
vital fable
lethal parcel
Gpu instancing would definitely be ideal but the original shaders weren’t compiled with it supported
vital fable
Ehh the game is definitely mostly cpu bound just because the stock code is prett...
If your game is CPU bound with 6000 Draw Calls I do not know what to say.
lethal parcel
It’s KSP not my game :p. Just working on a mod and trying to squeeze performance because I’m also working on a vr mod
Also I have a 3080 ti, so it may well be gpu bound for someone with a weaker card
In any case I will experiment with manually combining the meshes instead of using the batching utility. I think the potential downside is that it may not pick up all the relevant lights but that seems unlikely because there usually aren’t that many lights in the scene, maybe 10
And lack of culling support but again the meshes are pretty simple
thin atlas
I though you could make 1 single draw call by batching every index in one array....
You can, but by keeping it separate, Unity can still cull individual renderers. I don't think there's a big performance difference between one combined draw call vs multiple consecutive draw calls if there's no state change between them. (If there was, SRP Batcher wouldn't work as well as it does)