A few days ago it was confirmed that none of AMD’s current GPUs are capable of supporting the new rendering features in DirectX 12 level 12_1, namely Conservative Rasterization and Rasterizer Ordered Views.
I already mentioned that back when Maxwell v2 and DX11.3 were introduced.
Back then a guy named ‘Tom’ tried to push the idea that these features are supported by Mantle/GCN already. When I asked for some specifics, it became somewhat clear that it would simply be some kind of software implementation rather than direct hardware support.
When I asked for some actual code to see how complex it would actually be to do this in Mantle, there was no reply.
Software approaches in general are no surprise. AMD demonstrated a software version of order-independent-transparency at the introduction of the Radeon 5xxx series.
And a software implementation for conservative rasterization was published in GPU Gems 2 back in 2005.
So it’s no surprise that you can implement these techniques in software on modern GPUs. But the key to DX12_1 is efficient hardware support.
That should have already confirmed that AMD was missing out on these features, at least on the current hardware.
Rumours have it that a large part of the new 3xx series will actually be rebranded 2xx GPUs, so nothing changes there, feature-wise.
So the only unknown is what the new Fiji chip is going to be capable of, for the Radeon Fury series.
The most info I’ve found on the Fiji chip so far is a set of leaked slides posted at Beyond3D.
But it still isn’t clear whether it supports conservative rasterization and rasterizer ordered views. The slides do not mention it, which is not a good sign. They do mention “Full DX12 support”, but only in combination with resource binding tier 3 (a feature that Maxwell v2 does not support).
I think it is safe to assume that if they supported conservative rasterization and ROV’s, that we would have heard of it by now, and it would definitely be mentioned on the slides, since it is a far more interesting feature than resource binding tier 2 vs tier 3.
So I contacted Richard Huddy about this. His reply pretty much confirmed that conservative rasterization and ROV’s are missing.
Some of the responses of AMD’s Robert Hallock on Twitter also point to downplaying the new DX12_1 features, and just pretending that supporting DX12 is supporting DX12, regardless of featurelevel.
Clearly that is not the case, 12_1 includes some rasterizing features that 12_0 does not. But if AMD needs to spread that message, with a new chip being launched in just a few days, I think we know enough.
Oh wow, there goes the hate campaign again:
Does this mean that Nvidia didn’t support DX 11 because they couldn’t do DX 11.1 or feature level 11_1? Does the fact that Nvidia downplayed the benefits of 11.1/11_1 mean that they didn’t support DX 11? That guy just sounds like an idiot/fanboy when he says that even if it may not have been his intention.
Of course if he said the same things about Nvidia back then, well, then he’s just an idiot. 🙂
Is it just me, or is this logic broken beyond repair? I don’t know what to make of this…. “nVidia didn’t support DX11 because they couldn’t do DX11.1?”
How is that an analogy to this? Nobody said AMD doesn’t support DX12. I’m just saying that the statement AMD is making is “DX12 is DX12, regardless of whether you support level 12_0 or 12_1”.
I’m just pointing out the obvious flaw in AMD’s statement: there are different levels in DX12 because they are different.
Not to mention that the situation with DX10/DX10.1 or DX11/DX11.1 are very different to the current situation. Namely, those were updates to the API that were done after the API had been on the market for years already. Back when DX10 and DX11 were launched, there was no concept of DX10.1 and DX11.1 respectively. And neither nVidia nor AMD had DX10.1/DX11.1 hardware at the launch of DX10/11.
In this case, there are different feature levels for DX12 introduced right at the launch of the API. So that does not compare at all to the situation with earlier versions of DX.
So who is sounding like an idiot/fanboy here?