[MW Forums]

With so much attention paid in recent weeks to the Mac conversion of Doom 3's performance, it's timely that Apple has posted "Optimizing OpenGL Data Throughput on Mac OS X," a new feature on the Apple Developer Connection Web site. The information isn't specific to game developers -- it's practical information suitable to any Mac OS X developer working on projects that can benefit from faster OpenGL performance. more

[irolley]

The thing is they might have come up with this document WHILE working with Aspyr. Which means that those hints might already be implemented in Doom3.

[Steve_S]

In reply to:

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The thing is they might have come up with this document WHILE working with Aspyr. Which means that those hints might already be implemented in Doom3.

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I'm just guessing of course, but Doom3 was designed for OpenGL. I'd be surprised if Aspyr did much in the way of further OpenGL optimization above and beyond what id has already done. I believe this document was to help developers who are creating new titles or perhaps those that are converting games from Direct 3D, etc.
Steve

[Peter Cohen]

The point is not that Doom 3 doesn't haven't such optimizations; the point is that with so much public scrutiny on its performance, it's incumbent upon OpenGL developers to make sure they're getting every bit of performance they can out of their own applications.

[rlavere]

By all accounts, Aspyr DID work closely with Apple. From arstechnica.com:

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Glenda Adams of Aspyr Media, the company that ported the game to the Mac, has offered us her take on the situation.
"The truth to Doom 3 OS X performance is that there isn't one magic low hanging fruit optimization that will fix it. Engineers at Aspyr/id/Apple/ATI/nvidia haven't 'overlooked' something, or just blown off an easy fix for some reason. We held the game for over 4 months purely for optimization, its not like it was rushed out for a certain date," she wrote.
Adams also noted that the game is currently "as optimized as it was going to get with the current Mac OS, compilers, and hardware," and noted that additional delays in releasing the game wouldn't really suit anyone. One might ask, then, why it is that the top of the line G5, which performs admirably in other circumstances, seems to trail the PC so clearly in this instance. Adams added:
"The biggest remaining optimization is below the surface of OpenGL, between the framework/drivers and hardware. This is where the PC gains the most advantage. But even that may not be all of the difference. Everything else I've mentioned in different forums, from data alignment to float/int conversions and compiler differences play a factor. If gcc can't do the same level of cross-module inlining on the Mac as the PC compiler, maybe thats a 1% overall hit. Maybe its 0.005%, maybe its 5%. If the PowerPC could convert a float to an int without writing it out to memory, maybe thats another .005%, or another 1%. Those things are so difficult to measure, and immensely difficult to re-engineer away."

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[melgross]

I have a great deal of respect for the developers of Doom and those at Aspyr. That doesn't mean that some basic error hasn't been made somewhere that precludes a performance enhancement .
I've seen programming errors over the years that were only caught a long time afterwards, despite close scrutiny at the time.
Programming is like publishing, you need an outside editor to check for errors. If the same teams go over their work ten times, they may still not catch it.
This Optimization help from Apple might be in response rather than as a work of collaboration with Aspyr

[Peter Cohen]

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This Optimization help from Apple might be in response rather than as a work of collaboration with Aspyr

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Alternately, it may have nothing to do with it whatsoever, and may simply have been posted by Apple as a helpful "how to."
Again, this wasn't meant as an indictment against Aspyr Media. In retrospect, I'm sorry to have given people an opening to use it as an excuse for armchair quarterbacking and idle speculation.

[AlanCE]

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'm sorry to have given people an opening to use it as an excuse for armchair quarterbacking and idle speculation.

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Then tell me what the hell i'm supposed to do at work all day! /forums/ubbthreads/images/graemlins/wink.gif

[nek]

Glenda Adams also provided a thorough explanation of possible reasons for why Doom is slower on the Mac on Barefeats. It seems likely that these tips from Apple came from their work together with Aspyr (also involving ATI and nVIDIA). But she also mentioned that she expects further improvements in the future as happened with Quake 3.

[Steve_S]

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In retrospect, I'm sorry to have given people an opening to use it as an excuse for armchair quarterbacking and idle speculation.

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Huh? You have to love the irony of someone in your position to complain about "armchair quarterbacking" and "idle speculation". No offense, but your "news stories" are often full of both. On top of that, this is a forum that openly invites such discussion. Finally, as you elluded to, by even mentioning "Doom3" in your "story", you most certainly did invite such commentary.
Steve