On Wed, Feb 13, 2019 at 11:51 AM Axel Davy <davyax...@gmail.com> wrote:
> On 13/02/2019 17:42, Marek Olšák wrote: > > On Wed, Feb 13, 2019 at 2:28 AM Axel Davy <davyax...@gmail.com> wrote: > >> On 13/02/2019 06:15, Marek Olšák wrote: >> > I decided to enable this optimization on all Pro graphics cards. >> > The reason is that I haven't had time to benchmark games. >> > This decision may be changed based on community feedback, etc. >> >> >> Could the decision to run the optimization be based on some perf >> counters related to culling ? If enough vertices are culled, you'd >> enable the optimization. >> > > No, that's not possible. When I enable this, all gfx counters and pipeline > statistics report that (almost) no primitives are culled, because the > compute shader culls them before the gfx pipeline. > > You would disable by default the optimization. The perf counters would > then be meaningful. If the perf counter tells you enough primitives are > culled, you'd switch to the optimization and would stop looking at the > counters. No need to enable if only a few things are culled. > > The best of course is that if you detect at some point the optimization is > worth it, it won't stop being worth it in a different game scene, but it > should be already a good filter, as if you never go above the threshold, > you definitely don't need the optimization. > I can actually read back the number of primitives not culled by the compute shader and the driver also knows the total number of input primitives. And when the compute shader is off, I can use pipeline statistics. > > > >> >> There seems to be an AMD patent on the optimization, I failed to see it >> mentioned, maybe it should be pointed out somewhere. >> > > Unlikely. It's based on this: > > https://frostbite-wp-prd.s3.amazonaws.com/wp-content/uploads/2016/03/29204330/GDC_2016_Compute.pdf > > And this is pretty much a simpler version of what I implemented: > https://gpuopen.com/gaming-product/geometryfx/ > > Marek > > > This is what I found: > > https://patents.google.com/patent/US20180033184A1/en > It looks similar (I'm not a lawyer), but I generate neither a transform shader nor a fetch shader. Marek
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