Multiple depth buffer for layer effect

[Dark_Photon]

@Alfonse_Reinheart

Also, if you’re dealing with this, look into multidraw functionality and gl_DrawID.

Yes, certainly to reduce CPU time consumption.

One glMultiDraw* caution though. If your subdraws contain very few vertices, this can lead to inefficiency on the GPU-side (more in the thread below). You literally end up with near-zero CPU time consumption for the dispatch (great!) but more GPU time consumption than you’d expect given the triangle and vertex counts.

So profile your frames. If you’re very CPU limited and far from GPU limited, this isn’t an issue and isn’t likely to be. Moreover, if you go glMultiDraw* as a first step, you can massage it into using glDraw* later if you find that you need it.

GPU vertex dispatch for MultiDrawIndirect and/or Instanced draw calls

Doing some reading, I see indications (but not outright statements) in GPU vendor documentation that GPUs do not pack: vertices across different instances in an instanced draw, nor vertices across different draws in a MultiDrawIndirect draw call into shared thread groups (warps or wavefronts). I also find devs on the net saying that GPUs do not do this, but without a pointer to vendor docs as the source. My question is, does anyone know whether this is (or is not) the case? (If so, I gue…