in. The odd situation that we have here is that code was proprietary to nVidia is identical to the standard advice both companies used ever since DirectX 10.1 came out and sorted out Anti-Aliasing calls. As we all know, DirectX 10.1 removes excessive passes and kills the overhead that happened in development of the original DirectX 10.0. Even if you have DirectX 10.0 hardware, in most cases that DX10.0 overhead is run over by DX10.1 if developers had adjusted their approach to MSAA.
By late August, Rocksteady got back to AMD and stated "that they [Rocksteady] will look back and try to sort that one out for Day One patch, but that it was too late to hit the Golden Master. We were expecting that Day One patch would contain that MSAA-enabler. They made a clear statement it is Rocksteady's intention to enable MSAA on our hardware. When the Day One patch arrived, we were disappointed that it didn't contain that support."
Rocksteady gave a clear intention to enable in-game AA code on AMD cards with a statement that found its way to Beyond3D Forum: "The form of anti-aliasing implemented in Batman: Arkham Asylum uses features specific to NVIDIA cards. However, we are aware some users have managed to hack AA into the demo on ATI cards. We are speaking with ATI/AMD now to make sure it’s easier to enable some form of AA in the final game."
Things turn out even more interesting when the game was released. On Batman: Arkham Asylum Forums, people experimented with nVidia code and got it to run on ATI hardware in a very trivial way - by changing vendorID from ATI to nVidia. On September 11, AMD's Ian McNaughton posted a very interesting post claiming that by changing the VendorID from ATI to nVidia; you would not only get AA selection inside the game, but also higher performance. There was a thread on Eidos' forums that explained how to enable in-game AA on ATI hardware, but it went the way of dodo birds:
"We don't know what happened there, we don't know did nVidia went back and stated "Hey, we wrote this code and pushed through our own QA and it is not O.K. for you to loosen it up and let it run on anyone's hardware but ours."
"We don't know if EIDOS or Rocksteady went back and think up some sort of excuse - I don't know, but proprietary claim I suspect, comes from some kind of track record from nVidia that the code was made by them and that they didn't wanted to allow it to run on our hardware.
I am not sure why Eidos came to such a conclusion that there was a rendering problem. People have been able to experiment to run that nVidia code on AMD hardware and as far as I am aware, never met a problem making it run. If you were to go to EIDOS discussion forum about this for the moment, they have posted how to turn the Anti-Aliasing on through the Catalyst Control Center, you can notice that one forum poster posted immediately after how to make in-game control work on AMD hardware. As far as I know, there is no issue about it. So, I suspect that EIDOS must have got confused, they probably had reports of corruption because of some other problem we had on that particular build of the game. They also might have pressure; it is my guess from nVidia - not to allow this MSAA code to run on our hardware."