Information about UE4 GBuffer

Development Rendering
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1

I’m pretty desperatly searching for information about the GBuffer, but just can’t find any.

Things that interesst me:

  • How big is the GBuffer? How many bits does it uses per pixel?
  • How does the layout of the GBuffer look like?
  • Is it possible to make the GBuffer “slimmer” ?
  • What is r.GBuffer and r.GBufferFormat for?

I would very appreciate any kinds of info!

P.S.: Sorry if this isn’t the right place to question.

2

I found in the ConsoleManager.cpp some clues:

  • r.GBuffer: 0=Do not use GBuffer (fast minimal rendering path), 1=Use GBuffer [default]. (However it caused artifacts which rendered the game unplayable.)
  • r.SceneColorFormat: (Interessting options which affects some of the GBuffer I think) Defines the memory layout (RGBA) used for the scene color. Affects performance, mostly through bandwidth, quality especially with translucency.
3

You would like to check out FSceneRenderTargets class and EncodeGBuffer function in DeferredShadingCommon.usf. You would get a better understanding on GBuffer layout. As said, you could slim GBuffer size according to your specific requirement. You must find a balance among performance, vram size and quality.

4

Hello ,

Here is an in depth look at g-buffers and how they work. First paragraph discusses how to choose the size of the G-Buffer.

Thanks,