ATI's 'Chuck' on HDR with AA in Ghost Recon: Advanced Warfighter
When the demo of Ghost Recon: Advanced Warfighter for the PC became available last week, one of the first and loudest complaints to come out of our forums was that the game didn't allow for the use of anti-aliasing in any shape or form, leaving users with jaggies galore wherever they cared to look in the game.
As the game utilises High Dynamic Range rendering, it was already clear that there was no chance of NVIDIA boards supporting anti-aliasing in this title, but what of ATI? Thoughts immediately turned to recent developments with Elder Scrolls IV: Oblivion, and ATI's special driver that allowed for High Dynamic Range and anti-aliasing to be used in this title. The question on everybodies lips was - Could ATI pull off the same trick in Ghost Recon: Advanced Warfighter?
Of course, there is only one man at ATI to whom this question can be posed - The mysterious driver developer known only as 'Chuck'. So, over the past few days we set out to communicate with this international man of mystery - 'X's were taped to windows, cryptic messages were left in the classified sections of newspapers, boxes of chocolate were squirreled into Terry Makedon's bedroom late at night while he showered. And finally, we had it - An official response from ATI's 'Chuck' regarding the possibility of anti-aliasing being enabled in Ghost Recon: Advanced Warfighter.
What did he have to say? Here's the quote, directly from the man himself, in full:
The rendering path in G.R.A.W is very different from most games in that it appears to make extensive use of multiple render targets (MRTs). (This is where one draw operation can write different values to different surfaces.)
The DX9 spec doesn't allow multi-sample AA when using MRTs and our hardware requires that all of the destination surfaces either have AA or not. This means that in order to get AA in G.R.A.W. we'd need to have lots of AA surfaces and perform a ton of AA resolves. The end result would be slow and require much more texture memory. It's not 100% impossible, and I'm not giving up on the possibility, but there is no playable solution right now.
So, there you have it - There is still a chance of being able to use anti-aliasing in Ghost Recon: Advanced Warfighter on ATI hardware, but seemingly only a very slim one. Our assumption was that the use of deferred shading for the game's lighting technique was the prime suspect, but it seems from ATI's own analysis is that it's the use of multiple render targets that cause the issue here.
I'd like to thank 'Chuck' for his time and thoughts on this issue - But I can't, because he's returned to his secret underground lair in a parallel dimension. So, instead, I'd like to thank Terry Makedon for his time and efforts, and hopefully he can pass our gratitude on to 'Chuck' via Morse Code. Or something.