Why don't nvidia cards support HDR+AA?

[imported_goku]

I don't understand why nvidia cards aren't able to support HDR+AA and how come they won't be able to ever allow this feature on their cards? Is this equivalent to the PS2 no supporting AA where it really could but there are no practical scenarios where you COULD enable it?

 

[TheRyuu]

Supposedly, the G80 can do HDR+AA (more specifically FP32 HDR+AA)

It's really more specifically FP16 and FP32 HDR+AA.
You can't really (technically) just say HDR+AA since this is incorrect. Valves Source engine uses HDR (glorified bloom using pixel shaders to do it) and nvidia cards can do AA on it.

But their current G70 and G71 (and older NV40) chips cannot physically do FP16/32HDR+AA. It's just the way that the architecture is built I guess (maybe the way the chip handles the processing of the data?)

 

[Lord Banshee]

The hardware is not possible to do this... There are tricks like i think the Source Engine has a HDR and AA that works and AOE3 has it too but AOE3's method is very very slow.

 

[Nelsieus]

Yea, but luckily it will all be possible with Geforce 8800

Nelsieus

 

[imported_goku]

So then why is the ATI X1000 series able to do it?

 

[ShadowOfMyself]

Because Ati owns *puts on flamesuit*

 

[Nelsieus]

Originally posted by: goku
So then why is the ATI X1000 series able to do it?

Because R520 was a new architecture, and G70 was built on NV4*

Nelsieus

 

[schneiderguy]

Originally posted by: goku
Is this equivalent to the PS2 no supporting AA where it really could but there are no practical scenarios where you COULD enable it?

pretty much. NV40/G70 support SSAA + HDR --- NOT MSAA + HDR. SSAA is slow, and especially with the combination of HDR, will drag your framerate down to a crawl, if used. The only game that does SSAA + HDR on nvidia cards is AOE3

 

[Kromis]

Originally posted by: ShadowOfMyself
Because Ati owns *puts on flamesuit*

Have a Molotov cocktail!

I'm not an ATI or NVIDIA fanboy but I'd like you to die! j/k

 

[BFG10K]

So then why is the ATI X1000 series able to do it?

Because it has the hardware to allow MSAA to be applied to a floating point framebuffer. The G7x does not.

NV40/G70 support SSAA + HDR

No. AOE3 supports it because it's a software hack but you can't just enable X x Y AA modes on the G7x and expect to get AA in other HDR games.

 

[schneiderguy]

Originally posted by: BFG10K

NV40/G70 support SSAA + HDR

No. AOE3 supports it because it's a software hack but you can't just enable X x Y AA modes on the G7x and expect to get AA in other HDR games.

Originally posted by: schneiderguy
The only game that does SSAA + HDR on nvidia cards is AOE3

 

[Munky]

Originally posted by: schneiderguy

Originally posted by: BFG10K

NV40/G70 support SSAA + HDR

No. AOE3 supports it because it's a software hack but you can't just enable X x Y AA modes on the G7x and expect to get AA in other HDR games.

Originally posted by: schneiderguy
The only game that does SSAA + HDR on nvidia cards is AOE3

The point is that the game itself manually performs SSAA with HDR by rendering everything internally at a much higher resolution that the screen resolution. You can't just force SSAA in any HDR game because the card by itself can't do it.

 

[schneiderguy]

Originally posted by: munky

Originally posted by: schneiderguy

Originally posted by: BFG10K

NV40/G70 support SSAA + HDR

No. AOE3 supports it because it's a software hack but you can't just enable X x Y AA modes on the G7x and expect to get AA in other HDR games.

Originally posted by: schneiderguy
The only game that does SSAA + HDR on nvidia cards is AOE3

The point is that the game itself manually performs SSAA with HDR by rendering everything internally at a much higher resolution that the screen resolution. You can't just force SSAA in any HDR game because the card by itself can't do it.

ah okay I understand

 

[BFG10K]

Yeah, your original comment "NV40/G70 support SSAA + HDR" is not accurate.

 

[GundamSonicZeroX]

I heard somewhere that the same 'part' that does the HDR is the same 'part' that does the AA. Is that true?

 

[BFG10K]

No, it's because nVidia lacks the hardware to perform AA on a floating point framebuffer.

ATi has that hardware.

 

[Cookie Monster]

Hardware limitation.

As simple as this.

G80, nVIDIAs new architecture can achieve FP16 and FP32 HDR.

The X1 series/7 series cannot do FP32 HDR. (unless im wrong)

Once again, hardware limitation.

 

[Munky]

Originally posted by: Cookie Monster
The X1 series/7 series cannot do FP32 HDR. (unless im wrong)

Once again, hardware limitation.

Actually, the x1k cards can do FP32 HDR, but they can't do AA in that mode, at least accoding to the hardware caps reported by the driver. I wonder what the visual difference would be like between FP16 and FP32.

 

[Cookie Monster]

Originally posted by: munky

Originally posted by: Cookie Monster
The X1 series/7 series cannot do FP32 HDR. (unless im wrong)

Once again, hardware limitation.

Actually, the x1k cards can do FP32 HDR, but they can't do AA in that mode, at least accoding to the hardware caps reported by the driver. I wonder what the visual difference would be like between FP16 and FP32.

Thanks. I cant wait for an indepth review from beyond3d.