More comments from John Carmack about xbox360, ps3
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Dave Baumann said:
Dave is 100% right. IHVs can provide full ICDs in Vista, just like in XP and earlier OSes.
The ONLY difference is that when the ICD is loaded, the pretty 3D accelerated Aero UI and desktop compositing will be temporarily reverted to the XP UI if you are running in WINDOWED MODE. This is not that bad a thing, since if you are running a technical app that requires the ICD, you probably would have turned off the fancy 3D GUI in the first place to get the best 3D performance from your hardware.
FULL SCREEN apps like games are unaffected, since you're not going to be rendering the desktop while such an app has control of the hardware anyway.
The reason for this is that the ICD architecture assumes exclusive access to the 3D hardware, and obviously that is impossible with the Vista model of being able to share the 3D hardware among all apps on the desktop. Yes, MS could have undertaken an effort to redesign the ICD architecture to allow sharing of the 3D hardware with the 3D accelerated desktop, but it was decided that this would be too much work to get right for Vista in a timely manner.
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Gubbi said:
An XP ICD is a seperate driver stack, entirely independent of DX, and they will be backwards compatible with Vista, AFAIK.
If you don't have an IHV supplied ICD, Vista will use an emulator which does sit on top of DX10 and is limited to OpenGL 1.4. This is intended for light duty.
An IHV has two options to implement a true ICD on Vista: use the XP driver model and write one completely independently, or use the Vista driver model, and write one that uses the DX kernel mode component for support for allocating video memory, managing DMAs, etc. Neither option causes OpenGL API calls to be "virtualized" through D3D10.
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http://www.next-gen.biz/index.php?option=com_content&task=view&id=2164&Itemid=2
(I first found that link from: http://www.ga-forum.com/showthread.php?t=83657 )
(I first found that link from: http://www.ga-forum.com/showthread.php?t=83657 )
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Powderkeg said:
Sorry to be a complete n00b, but out of interest how time consuming is it to 're-program' an entire game/engine from OpenGL>DX or visa-versa? Does the entire interpreter & renderer have to be re-written, literally line by line or do modern software compilers make it much more fluid and generally easier?
Although no support for non-MS API's (i.e a completely closed environment) sounds right, I always thought up until now that the 360's OS kernel (roughly based on WinNT, right?) and/or the drivers somehow supported OpenGL just like PC Windows does...
Thanks.
Ken2012 said:
I imagine now days, especially if you are planning multiplatform, you'll make some sort of abstraction layer between the game engine and the api. Then all you have to do is rewrite the abstraction layer (for whatever platform you want) and you should be mostly done (of course you'll have to tweak stuff here and there, and likely rewrite other stuff, but most of the work would be settled there). It's much easier to keep track of. If you wanted to switch your game from OpenGL to DX then you would have to manually change all the api calls (I think they are pretty comparable and most of the functions take similar arguments so it just takes time).
Assuming a decently structured piece of software, replacing renderer backend should be a relatively trivial thing to do.Ken2012 said:
Especially when we're talking about backends that essentially support the same functionality.
Assuming OGL is the only option on PS3 (though with multiplatform, what's the option of least resistance is generally most relevant, so your point is still valid).Shifty Geezer said:
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It will have a bigger effect as developers get to grips with WF2.0/DX10, considering the xbox 360 has some WF2.0 features will allow for games to be ported to xbox 360 with less tailoring.
But that is pointless people will want to take advantage of new graphical features supported by WF2.0 and the countless PC gamers who want the best GPU's on the market, in which case would need a PC configuration that has Vista installed.
Plus as developers get more experience with DX they will start to realize they are less able to port the experience to an openGL environment and stray from the idea. (openGL will be come nothing more than a PS3 graphics API)
Consoles a side, Nvidia are really guna feel Microsoft's revenge in the PC market.
But that is pointless people will want to take advantage of new graphical features supported by WF2.0 and the countless PC gamers who want the best GPU's on the market, in which case would need a PC configuration that has Vista installed.
Plus as developers get more experience with DX they will start to realize they are less able to port the experience to an openGL environment and stray from the idea. (openGL will be come nothing more than a PS3 graphics API)
Consoles a side, Nvidia are really guna feel Microsoft's revenge in the PC market.
GB123 said:
I doubt they'd require much less tailoring than they do currently. Unfied shaders don't require a specific approach - you're still writing discrete pixel and vertex shading programs - and SM4.0 shaders won't run without modification on SM3.0 hardware. Geometry shaders would require significant changes to run on the CPU.
GB123 said:
I think it's more apt to say that DX is "nothing more" than a Windows API. Weighing the importance of the non-Windows gaming market, I don't think it's at all clear it is smaller or less important than the windows one. Even PC-centric devs are being forced to pay attention to the console market because the PC market is becoming less and less lucrative relatively speaking, and Xbox is the only windows gaming platform (with currently a minor marketshare).
Why do you think MS launched Xbox? Windows and DX was being marginalised as a gaming platform.
GB123 said:
Hardly. The Mac will never see a native DirectX runtime and neither will linux (though there are some good efforts by the Open Source community to mimic these). Any other platforms that show up with a respectable 3D performance (mobiles/whatever) are going to use OGL which can be very modular (just pick a version). The truth is that if you want performance and multiplatform (except Windows + xbox) you'll need to use some form of OpenGL.
In other words, I agree with Titanio.
Powderkeg said:
It is more than likely that the promotion of DX was part of the reason for Microsoft's console venture. Microsoft needs to expand it's income sources as it realises in the longer term that relative revenues from the OS business could be under threat from future trends in home computing.
If Sony or Nintendo had agreed to use MS OS/API, MS wouldn't have created XBox.Powderkeg said:
A recent interview with John Carmack:
http://www.buzzscope.com/features.php?id=1248
"JC: They are both powerful systems that are going to make excellent game platforms, but I have a bit of a preference for the 360’s symmetric CPU architecture and excellent development tools. The PS3 will have a bit more peak power, but it will be easier to exploit the available power on the 360. Our next major title is being focused towards simultaneous release on 360, PS3, and PC."
The cell chip can do 218 gflops. The xcpu can do 115 gflops. The RSX can do 136 shader ops. The Xgpu can do 96 shader ops. In a previous interview, Carmack calls the PS3 "marginally" more powerful. Now he says pretty much the same thing: "a bit" more powerful. (raw gpu and cpu power)
Wouldn't you agree that the PS3 is not "marginally" and "a bit" more powerful, but alot more powerful (raw performance) than Xbox 360?
http://www.buzzscope.com/features.php?id=1248
"JC: They are both powerful systems that are going to make excellent game platforms, but I have a bit of a preference for the 360’s symmetric CPU architecture and excellent development tools. The PS3 will have a bit more peak power, but it will be easier to exploit the available power on the 360. Our next major title is being focused towards simultaneous release on 360, PS3, and PC."
The cell chip can do 218 gflops. The xcpu can do 115 gflops. The RSX can do 136 shader ops. The Xgpu can do 96 shader ops. In a previous interview, Carmack calls the PS3 "marginally" more powerful. Now he says pretty much the same thing: "a bit" more powerful. (raw gpu and cpu power)
Wouldn't you agree that the PS3 is not "marginally" and "a bit" more powerful, but alot more powerful (raw performance) than Xbox 360?
bbot said:
I think this explains his view "it will be easier to exploit the available power on the 360"
if doom 3 took them 4 years, how long will it take to make a game and try to exploit the power of the cell, and given that xenos is supposed to be more efficient the gpu's should be about even
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